Catholic Encyclopedia
Church Fathers
Classics Library
Church Documents
Prayer Requests
Ray of Hope
Social Doctrine

G D His Existence And His Nature -Rev. R. Garigou-Lagrange, O.P.


The agnostic denial of the ontological validity of first ideas and their correlative first principles is nothing else but the negation of the abstractive intuition of the intelligible, commonly called by St. Thomas and the Scholastics "the simple apprehension of the intelligible in the sensible," or "indivisibilium intelligentia."

See St. Thomas, De Anima, Bk. III, Lect. 2; Met., Bk. IV, Lect. 6; De Veritate, q. 14, a. 1.


Empirical Nominalism reduces the concept to a composite image with a common name. According to Kant, the concept is merely an a priori form of thought, its sole purpose being to unite phenomena. According to these theories, all intuition of the intelligible, no matter how imperfect, is thus suppressed.

We certainly have no intuition of intelligible being considered in its pure state, as if we were pure spirits. This was the error of Plato, Spinoza, and the Ontologists. But we have a certain intuition of intelligible being, derived by the process of abstraction from being as made known to us by the senses.

See Aristotle, De Anima, Bk. III, Ch. VII; Lect. 12 of St. Thomas: "To function intellectually the soul has need of the phantasms—the intellect understands the natures of things in the phantasms." See also Summa Theol., Ia, q. 12, a. 4; q. 84, a. 7; q. 85, a. 1 and 5.


"Circa naturas rerum sensibilium primo figitur intuitus nostri intellectus, qui ratio proprie dicitur. Ex hoc autem ulterius assurgit ad cognoscendum spiritum creatum (it is to the natures of things as presented by the senses that our intellect first of all is directed, and this act is rightly called reason. From that, however, it proceeds farther, to acquire a knowledge of the purely immaterial in creation)." (St. Thomas, De Veritate, q. 15, a. 1, ad 7um). Just because man is not an angel, we must not, like the Empirics, practically identify him with the beast, nor must we claim, as Kant does, that his intellectual life is perhaps but a well-connected dream.

It is this imperfect intuition of the intelligible, united with abstraction, which we must briefly explain before we defend its ontological validity.


15) The intellectual apprehension of intelligible being and the intuition of its first principles.


What is meant by this imperfect intuition, united with abstraction, is sufficiently explained by St. Thomas in the First Part of his Summa Theologica, question 85, article 1. The cognizable object, he says, is proportional to the cognitive faculty. If this faculty is, like that of any of the senses, dependent upon some corporeal organ, it can have knowledge only of that which is material and sensible, precisely in so far as it is material and sensible. In the case of pure spirits, since the cognitive faculty is intrinsically and extrinsically independent of any corporeal organ, its proper object is immaterial being, not sensible, but purely intelligible; and if it has any knowledge of material things, this can be only because it views them from a higher plane, in that it has a direct intuition of them in the purely intelligible. Finally, if the cognitive faculty is, like the human intellect, intrinsically independent of any bodily organ, but nevertheless united with the sensitive faculties, its proper object is intelligible being as existing in sensible and individual matter, but not precisely as existing in such matter. Now, to know what happens to exist in sensible and individual matter, but not just as existing in such matter, is to abstract the immaterial from the sensible.

"But to know what is in individual matter, not as it exists in such matter, is to abstract the form from individual matter, which is represented by the phantasms." (Ia, q. 85, a. 1). "The things which belong to the species of any material thing, such as a stone, or a man, or a horse, can be thought of apart from the individualizing principles which do not belong to the notion of the species. This is what we mean by abstracting the universal from the particular or the intelligible species from the phantasms. (Ibid., ad 1m.) Not only does the active intellect throw light on the phantasms; it does more; by its own power it abstracts the intelligible species from the phantasm. . . . By the power of the active intellect we are able to disregard the conditions of individuality, and to consider the specific nature, the image of which informs the passive intellect." (Ibid., ad 4m.)


So then, whereas the pure spirit views material things from a higher plane, in that it knows them through the immaterial: the human intellect reaches the immaterial from a lower level, through the immateriality hidden under the veil of things material. (For a fuller development of this subject see St. Thomas, q. 85, a. 1.).

Whatever the Agnostics may say about it, this consideration or imperfect perception of our intellect differs essentially from sensible intuition, in that it penetrates beyond the sensible phenomena. "The word intelligence," says St. Thomas (IIa IIae, q. 8, a. 1) "signifies a certain intimate knowledge, for it is derived from intus legere, which means, to read what is within (to read in anything its sufficient reason for existing). And this is evident when we observe the difference between the intellect and the senses. In matter of fact, sensible knowledge is concerned only with external and sensible qualities. Intellectual knowledge, on the contrary, penetrates to the very essence of a thing. The proper object of the human intellect is that essence or quiddity of sensible things, and of this it has at least a confused knowledge. [The animal sees the color of the plant, but we know what that plant is—matter endowed with vegetative life; and we know enough of the lower forms of life to realize that the smallest blade of grass, because it has life, is worth more than all the gold found in the earth. See Aristotle, De Anima, Bk. III, c. VI; St. Thomas, Lect. 11].  The specific nature of a thing is hidden under its accidents, just as the meaning of anything is contained in the written or uttered words, just as by means of symbols truth is expressed. . . . And the stronger is the light of reason, the better it can penetrate to the innermost nature of things."

Without a doubt, the natural light of our mind, while united with the body, is feeble when compared with the angelic, and above all with the divine intellect; still it is an intellectual light, and if it does not give us an immediate and distinct intuition of the essences of things, it at least acquires, in a general and confused manner, from the sensible phenomena, a knowledge of intelligible being,

See St. Thomas, Ia, q. 85, a. 3; De Veritate, q. 1, a. 1, and the Prologue to De Ente et Essentia. Also Cajetan in his commentary on the prologue to De Ente et Essentia, John of St. Thomas, in his Cursus Phil. Phys., q. 1, a. 3, particularly in the Dico 20, remarks as follows: "Prima ratio cognoscibilis a nostro intellectu naturaliter procedente est quidditas rei materialis sub aliquo praedicato maxime confuso, quod praedicatum est ens, ut concretum et imbibitum in aliqua re determinata, quae tunc occurrit cognitioni. Fere est idem ac cognoscere rem quoad an est. (What our intellect first of all acquires a knowledge of, is the essence of sensible things, but in a very confused manner, expressing it by the very general term of being. Thus it is that we arrive at the notion of being, for the first concrete object presents itself as such for our cognition. It is about the same as saying that we know something actually exists)." Then follows immediately a judgment about this particular thing. See St. Thomas, Ia, q. 85, a. 3; q. 86, a. 1.


and its most general laws, known as first principles.

This first knowledge is truly an apprehension, a mental perception, an imperfect intuition, associated with abstraction.

Cajetan, in his commentary on the De Ente et Essentia of St. Thomas (ed. de Maria, q. 1, p. 20), writes as follows: "Ad conceptum confusum speciei specialissimae requiritur et sufficit duplex abstractio: altera per actum intellectus agentis (illuminantis), scilicet separatio a singularibus; altera per actum intellectus possibilis, scilicet actualiter intueri speciem, et non actualiter intueri genus. Ita ad conceptum confusum actualem entis duplex est abstractio necessaria. For acquiring a vague concept of the species infima (specialissimae, as the Scholastics call it), what is required and is sufficient, is a twofold abstraction: the one is a process of the intellectus agens (the illuminative faculty), by which the species is separated from its individualizing traits; the other process pertains to the intellectus possibilis, in that it actually intues the species, but not the genus. Therefore, to acquire a vague concept of being, two kinds of abstraction are needed." What is here called intuition and abstraction, is nothing else but the abstractive process of the intellectus possibilis. St. Thomas and the Scholastics generally refer to it as simple apprehension (simplex apprehensio), and the expression, "the intuition of the first principles of being" is of frequent occurrence in their writings. It must be noted here that intuition is contrasted, not with abstraction, but with deduction.


The intellect considers, in sensible things, intelligible being and its most general aspects, without actually considering the sensible qualities; just as with words it is not the arrangement of the letters that arrests the attention, but the meaning of the words. This simple apprehension of intelligible being and the intuition of its first principles enables the mind to acquire a more complex knowledge by subsequent reasoning, and it judges of the validity of the same by referring again to those principles by means of which it obtained such knowledge. (See IIa IIae, q. 8, a. 1, ad 1 and 2; Ia, q. 79, a. 8 and 9; and De Veritate, q. 1, a. 12; q. 15, a. 1, Whether intellect and reason are different faculties). Hence, all reasoning starts first from intuition and ends again in this intellectual intuition by a reduction of all things to first principles. (See Ia, q. 79, a. 8). Therefore, our reason deserves to be called intelligence.

St. Thomas is very clear on this point. In De Veritate, q. 15, a. 1, he says: "Ratio comparatur ad intellectum ut ad principium et ut ad terminum; ut ad principium quidem, quia non posset mens humana ex uno in aliud discurrere, nisi ejus discursus ab aliqua simplici acceptione veritatis inciperet, quae quidem acceptio est intellectus principiorum. Similiter nec rationis discursus ad aliquid certum perveniret, nisi fieret examinatio ejus quod per discursum invenitur, ad principia prima, in quae ratio resolvit. Ut sic intellectus invenitur rationis principium quantum ad viam inveniendi, terminus vero ad viam judicandi. Unde quamvis cognitio humanae animae propriae sit per viam rationis, est tamen in ea aliqua participatio illius simplicis cognitionis quae in substantiis superioribus invenitur, ex quo vim intellectivam habere dicuntur. In referring the reason to intellect we may consider the latter in one sense as the principle, and in another sense as the terminus of the operations of reason; as the principle indeed, because the human mind could not argue from one thing to another unless it started the argument by the simple acceptance of some truth, and this, of course, is the acknowledgment by the intellect of certain first principles. In like manner, by no process of reasoning could one know anything for certain, unless what the reason has thus acquired be again examined in the light of those first principles to which reason submits its findings. Thus, the intellect assumes the role of principle in the acquisition of truth and becomes the terminus when it passes judgment on the same. Therefore, although human knowledge commences with the reasoning faculty, nevertheless there is inherent in this same faculty some of that simple knowledge possessed by beings of a higher order, and on this account they are said to have intellectual power." (See also Ia, q. 79, a. 8).


If our intellect were more powerful, there would be no need of this investigation, which by a series of judgments and conclusions proceeds from first to more complex ideas, from a confused knowledge of essences to a more distinct knowledge of them (definition), and then, by means of this knowledge, deduces the various properties of a being. By a simple act of intuition the intellect would then have all at once a perfect knowledge of things; it would have a direct and distinct perception of their essences, and in them their properties. It would instantaneously comprehend the full import of the principles and would immediately perceive in them the truth of the conclusions. It is in this manner that the Divine Intellect knows all possible truths by a simple intuition of the Divine Essence. And the angels are so far superior to us that they know a greater number of things by means of fewer ideas, immediately perceiving them in all their aspects. The angels may be viewed as spheres of intellectual light, those of the higher orders becoming brighter, the nearer they are to God; and those of the lower orders gradually flickering and finally dying out in the obscurity of material things. (See Ia, q. 85, a. 5; q. 58, a. 3 and 4).

Our power of intuition is feeble, and that is why it is so divided (morcelated). Nevertheless, it is truly an intellectual intuition, an intellection infinitely superior to sensation. It is feeble and cannot immediately, by its own power, reach the source of all that is intelligible, namely, the Divine Essence. It cannot perceive things in the brightness of their pure intelligibility, but only in the obscurity of the senses. The reason for this is that our intellect is united with a body, and in point of mental vision is, as Aristotle remarks (II Met., c. 1), like the owl, whose power of vision is so feeble that it is blinded by the light of the sun and can see only at night. (S. theol., Ia, q. 76, a. 5).

Because our power of intellectual intuition is feeble, and cannot grasp the intelligible essences of things except in the obscurity of sensible qualities, thus slowly deducing their properties, it is of necessity divided (morcelated). It may be compared with the eyes of certain insects, in which the image of things seen resembles a sort of mosaic, which sufficiently preserves the general outline of the objects, though no longer clearly distinguished from each other.

Nevertheless, as soon as we are able to reason, it is only in the obscurity of things perceived by the senses that we detect intelligible being and its fundamental principles. "That being is what our intellect first of all sees in anything," is a frequently recurring statement of St. Thomas. "This is what is more known for it, and by which it knows everything else; and every idea presupposes the idea of being, just as every demonstration is based upon the first principles of being."

St. Thomas, in De Veritate, q. 1, a. 1, writes as follows: "Sicut in demonstrationibus oportet fieri reductionem in aliqua principia per se intellectui nota, ita investigando quid est unumquodque. Alias utrobique in infinitum iretur; et sic periret omnino scientia et cognitio rerum. Illud autem quod primo intellectus concipit quasi notissimum, et in quo omnes conceptiones resolvit, est ens. Just as in demonstrations there must be a reduction to certain first principles directly known by the intellect, so also it must be when inquiring into the nature of anything. Otherwise, in both cases there would be no end to the process; and this would mean that all scientific knowledge and the cognition of things were completely hopeless. That which presents itself first of all to the intellect as the best known, is the concept of being, and it is into this concept of being that it resolves all other concepts."


St. Thomas often mentions also the other first concepts which, together with that of being, are included in the first principles; for instance, unity, truth, goodness, etc.

On this point he writes: "There are certain universally known concepts which are the natural endowments of the human intellect, such as those of being, unity, goodness, and others of this kind; by means of these concepts the way in which the intellect comes to know the quiddity of anything is the same as that by which it arrives at conclusions deduced from first principles." (St. Thomas, Quodlibet., VIII, a. 4).



16) How shall we defend the ontological validity of our intellect and of its first ideas?


This ontological validity cannot be demonstrated by any direct method, for, like the necessity of first principles, it is an immediately evident truth. The immediately connected subject and predicate do not admit of a demonstrative middle term. All that we can do is to explain the meaning of the subject and the predicate, what is meant by intellect or the idea of being on the one hand, and, on the other, what is ontological validity. This explanation will immediately enable us to see that intelligence essentially implies a relation to being. This explanation may be presented in the form of a syllogism; it is not, however, strictly speaking, a direct demonstration, but can at most be called a direct defence. First evidences can be defended, but, not directly demonstrated; for an attempt at demonstration would result merely in a vicious circle, since one would have to assume as true what remains to be proved, to wit, the ontological validity of first principles.

Even the Agnostics, in spite of their system, as soon as they cease to philosophize, or even whilst they philosophize, are naturally forced to admit—as their language proves—that the direct purpose of the intellect is to acquire knowledge, that the idea of being is the idea of something real, that the principle of contradiction is a law of real objects, and not merely of thought, and that the absurd is as incapable of realization as it is inconceivable. Not one of these propositions can be demonstrated directly; it is sufficient that the meaning of the terms be understood.

But if the ontological validity of our intellect, and of its first ideas and its first principles, cannot be directly demonstrated, it admits of a sort of indirect proof, by the logical process of reductio ad absurdum, by a recourse to the principle of contradiction in so far as this principle is at least the necessary law of human thought.

We shall set forth, first of all, this indirect defence, which will enable us to realize more fully the force of the direct defence. Although the latter is but an explanation of terms, it contains virtually the solution of the problem of universals, by establishing the truth of Moderate Realism against Nominalism (or Empiricism), and against Subjectivistic Conceptualism (or Idealism in the Kantian sense), at the same time avoiding such exaggerated Realism as that of Plato, Spinoza, or the Ontologists.


17) Indirect defence of the ontological validity of first ideas.


We shall show: (A) that the denial of this validity leads the Empirical Agnostics or Idealists into insoluble difficulties; (B) that it leads them to absurdity.


A. Insoluble difficulties


The primary principles of reasoning are necessary and universal, and, moreover, cannot be the subject of doubt. How to explain this fact is an impossibility for Empiricism. We are conscious that we consider them as universal and necessary (we are quite certain that in absolutely all cases what is real cannot be non-real; that every beginning has a cause); besides, science demands this necessity and this universality. Now, experience, which is always particular and contingent, cannot account for these two characteristics. Concerning the principle of causality, we all—except the Positivists when they begin to philosophize—think that what happens must necessarily have a cause, and that the cause is not only followed by its effect, but produces the effect. Though we have actual experience of any effect only as the result of some voluntary effort on our part, we affirm this fact of all external causes, of the hammer striking the stone, and of the movement imparted by one billiard ball to another. Evidently, this universal and necessary principle does not arise from the recurring experience of phenomena that succeed one another. Moreover, there are just as many phenomena the causes of which the majority of men seek for in vain, as those, the causes of which they think they know. The child wants to know the reason for many things which cannot be explained to him. Yet, like a grown-up person, he is convinced that there is a reason for the phenomena which he cannot understand. Reason, therefore, is forced to accept the principle of causality as universally true, although experience does not establish the fact of universal causality. It is of no avail to invoke the principle of heredity, for our ancestors had no clearer conception of causes than we have. It is, therefore, contrary to reason for the Empiric to hold that there is no contradiction in the assertion of the possibility of things happening without a cause in some world unknown to us.

To deny the necessity and the absolute universality of principles means the reduction of the syllogism to a mere tautology and the complete destruction of the basis of induction. As a matter of fact, the major of a syllogism is but a generalization of particular cases and ought to include actually, and not merely virtually, the particular case which it is the purpose of the conclusion to establish. It presupposes that the case has been verified by experience. If causality were such as is stated above, then we could not find any universal principle by means of which we could formulate a truly general law from particular facts of experience. The principle that "in the order of nature the same cause in the same circumstances always produces the same effect," would have but the force of a strong presumption, based upon experience of past events.

The Kantian theory explains the universality and necessity of the principles, but denies their objectivity, naturally affirmed by the intellect with no less certainty than the two preceding characteristics. Philosophical reflection must give the explanation that is in agreement with nature and not in contradiction to it, and if one succeeded in showing that it is a "natural illusion," that our own intellect deceives us, he would at least have to explain why it is an illusion. On the other hand, by admitting the abstractive intuition of the intelligible, as Aristotle and the Scholastics understood it, the objectivity of the principles is explained, as well as their necessity and universality. The denial of this intuition led Kant to admit synthetic judgments a priori, i.e. blind judgments for which there is no foundation, intellectual acts for which there is no sufficient reason. This is tantamount to saying that the irrational is imbedded in the rational, and that ignorance is of the very warp and woof of knowledge. The mind cannot by the verb "to be" affirm real identity between subject and predicate (that a thing is such), except when it has evident certainty of this real identity, derived either from the analysis of the ideas (a priori), or else from a critical inspection of existing things (a posteriori). But if both of these evidences are wanting, then the affirmation is irrational, without reason. How can the intellect blindly assign to the phenomena an intelligibility that they in no way possess? In fact, as we shall see later on, the principle of causality and the other principles derived from the principle of sufficient reason, are analytical in this sense that the analysis of the ideas which they imply, shows there exists under the logical diversity of subject and predicate, a real identity, which cannot be denied without contradiction. As for the principles of Newtonian physics, everyone now-a-days admits that they are synthetic a posteriori. Another difficulty that arises from the preceding is, that the application of the Kantian categories to phenomena is arbitrary. Why is it that certain phenomena are classed under the category of substance and others under that of causality? Why is it that all cases of phenomena which succeed one another, such as that of night and day, may not be explained by the principle of causality? If, in order to avoid saying that it is arbitrary, we admit that we recognize the relationship existing in the objects themselves between substance, causality, etc., is not this the same as admitting the intuition of the intelligible? In that case, of what use is the category?

See Rabier, Psychologie, and ed., p. 282.


Finally, as Fichte remarked (and the Empirics repeated, though from an opposite point of view), there is no proof that the phenomena, if they are external to us, can always be assigned without the least violence to the various categories. What guarantee have we that the world of sensation will always be susceptible of becoming the object of thought, and that some day it may not exhibit the present spectacle of disorder, chance, and chaos?

Rabier, op. cit., p. 387.


From this latter difficulty the only way of escape for the Subjectivist is to maintain with Fichte that these phenomena proceed from the ego, and that just as God's knowledge is the measure of all things, so also is ours; but in that case the human mind could not be ignorant about anything, a theory which is most certainly contradicted by the facts of experience.

Thus the denial of the direct perception of the intelligible led Kant into insoluble difficulties; for he not only refused to concede to the metaphysical principles any force beyond mere phenomena, but even in the phenomenal order he admitted that their value is merely subjective, consisting in an arbitrary and precarious application of the principles. "In a word, the Kantian theory has in no way succeeded in giving to the principles that absolute and scientific certitude which it promised." (Rabier, ibid).


B) Indirect defence by the method of reductio
ad absurdum


The denial of the ontological validity of the intellect and of its primary notions results, moreover, in rendering absurd the essential elements of intellectual cognition, such as (a) the object, (b) the idea, (c) the principles, (d) the act of understanding, (e) the faculty of knowing.

a) The object. There is no longer a known object; what we know is merely an idea. Hence it follows that we cannot distinguish the object from the act of direct understanding (e. g., causality), from the object of reflex understanding (e. g., the idea of cause), since de facto the object of direct understanding is identical with the idea.

Now it is evident that the knowledge of causality and the knowledge of the idea of cause are two altogether distinct things; for the reflex act necessarily presupposes the direct act and cannot be identified with it except by a formal contradiction. (See St. Thomas, Summa Theologica, Ia, q. 85, a. 2). In other words, the intellect cannot reflect on itself as long as it has no knowledge of any definite object. Before it can reflect upon itself and its own ideas, it must have had something definite to think of; there is no such thing as thinking of nothing.

b) The idea. To maintain that in the process of direct intellection the idea is the object known, and not the means by which the intellect acquires knowledge of something else, means that we must admit that there is nothing real corresponding to what is represented by the idea, which is, therefore, an idea of nothing; in other words, the idea is an idea and no idea at the same time and in the same sense. To put it differently—to maintain that the idea, being an intellectual impression or expression of the human intellect,

The idea expressed interiorly, or the internal word (verbum mentis), is essentially "intentional," or relative to that which is expressed. It is not an expression of itself, or of nothing. The idea of a logical entity (e.g., the predicate of a sentence) is in reality merely the mental form of our thought, but this mental form is the result of a reflection made by the mind on direct ideas that express either possible or actually existing things.


corresponds to nothing real, is the same as saying that, at the same time and in the same sense, it is something relative and non-relative, which means the destruction of the very concept of both the idea and the mental expression. Fichte himself is forced to admit that this duality of representation and represented object is necessary for acquiring knowledge, and he goes so far as to conclude from this that if God is absolutely simple, there can be no knowledge in Him.

To be sure, an idea does not necessarily refer to an actually existing thing, but it must at least refer to something that is possible.

It is only through the medium of the senses or of consciousness that the human intellect in its present state acquires a knowledge of actually existing being.


It cannot refer to pure nothingness; for that would involve a contradiction, e. g., a square circle; and in that case we should no longer have an idea, but conflicting images. Now it is evident that there can be nothing contradictory in primary ideas, because of their simplicity. (See Ia, q. 85, a. 6).

c) The principles. The Agnostic who doubts the ontological validity of primary ideas, must also doubt that of correlative principles, especially the validity of the principle of contradiction, which is founded on the notion of being. The Agnostic, though admitting that the absurd is inconceivable, must doubt whether it is actually impossible. He concedes that a square circle is inconceivable, but from his point of view a square circle is not evidently impossible of realization. It might be possible for some canny genius to produce something which at the same time and in the same sense exists and does not exist. Now, this doubt is absurd; for a being supposed to exist and not to exist at the same time, would both correspond and not correspond to our idea of being, and as this idea is simple, there can be no question of a partial correspondence. The supposition, even subjectively considered, is inconceivable.

See St. Thomas in his Commentary on the Metaphysics of Aristotle, Bk. 4, where he defends the principle of contradiction.


d) The act of thinking. The Agnostic from his point of view cannot be aware of the reality of the act of thinking; all that he can know is the representation of this act. And even if he were directly conscious of its reality, he is not absolutely certain of this fact, for if he doubts the objectivity of the principle of contradiction as a law of being, if the real is in itself susceptible of contradiction, there is nothing to assure him that the action which he regards as real is actually real. If being is not the primary and formal object of the intellect, the intellect will never acquire any knowledge of being; admitting the hypothesis, the Phenomenalists are manifestly in the right. It was thus that the seventeenth-century Thomist Goudin (Philosophia, ed. 1860, t. IV, p. 254) refuted the claim that "cogito, ergo sum" is the first of all principles, more certain than the objective principle of contradiction. Aristotle had shown in his defence of this principle (Meta., Bk. IV) that anyone who in the cognitive order refuses to start from the idea of being (as the primary and formal object of the intellect), and from the first principle implied by it, denies himself the right to affirm anything, either about being, or about the existence of his own thought, or even his own ego. "In what way, then, does this or that man differ from the plant, which is entirely devoid of knowledge? He must imitate Cratylus, who, incapable of the least assertion, contented himself with moving his finger." (Met., Bk. IV, chs. iv and v).

e) The intellect. To doubt the ontological validity of primary ideas and first principles, ends in making the intellect itself absolutely unintelligible and absurd. It simply means to doubt that the intellect and intelligible being are essentially related to each other. Now this relationship is included in the notion we have of intellect, and its denial means the denial of the intellect itself; for in that case there would be no intelligible object corresponding to the intellect, which is absurd.

The Agnostic of the sensist type classes the operations of the intellect in their final analysis amongst those which belong to the senses, the sensible memory and the imagination.

According to the Agnostic of the idealistic type, there are two ways of viewing the human intellect, and both of them are meaningless. (α) With Kant, the Agnostic may deny to the intellect all passivity with regard to intelligible being, and admit merely the passivity of the senses with regard to phenomena; hence, for the rational and evident principles by which the intellect can establish contact with being, the Agnostic must substitute synthetic a priori principles, which are blind, unmotivated, and irrational syntheses. Thus, the irrational becomes the essential structure of reason, and the intellect, deprived of its relation to intelligible being, which is its formal object, is rendered meaningless. (β) On the other hand, he may, with Fichte, deny absolutely the passivity of the human intellect with regard to phenomena as well as to intelligible being. In that case he must identify the human with the divine intellect, whose knowledge is the cause of things, and it would follow that the human mind, the source of all intelligibility, must be omniscient ab aeterno, and no ignorance of any kind is possible. (See Ia, q. 79, a. 2).

The above-mentioned remarks outline the indirect defence of the ontological validity of primary ideas considered in their general aspect. The Agnostics, in denying this validity, are confronted with the insoluble difficulty of making an absurdity of all the essential elements of intellectual knowledge. In order to prove the natural range of the intellect with regard to being, the Agnostic deprives the intellect of its essential relationship to being. It is as if one were to break a spring in order to test its elasticity.


18) Direct defence of the ontological validity of primary ideas.


As we have previously remarked, there is no question here of a direct demonstration. What immediately appeals to one as immediately self-evident cannot be directly demonstrated. All that one can do is to explain the terms, so that their immediate connection may be more clearly perceived, and then to solve the objections.

First of all, we shall make a few general remarks upon primary ideas and their correlative principles. Following the logical order, we shall consider: (a) the ontological validity of the intellect, (b) the validity of primary ideas in general; which we shall confirm (c) by showing that being constitutes the very basis of judgment and reasoning. Then we shall answer the objections.

a) The intellect. The intellect is a cognitive faculty superior to the senses. Has it ontological validity? In other words, can it acquire knowledge not only of the phenomena perceived by the senses and the consciousness, but also of being itself (τὸ ὃν), of which the phenomena are but the sensible manifestation? A proper understanding of what is meant by the word "intellect" will answer this question.

Every faculty, says St. Thomas, must have its formal object, to which it is naturally ordained, to which it attains first of all, and by means of which it comes to know everything else. Thus, the formal object of the sense of sight is that sensible quality known as color, for nothing is visible except by means of color; sound is the formal object of the sense of hearing; consciousness has for its object the internal impression made upon us by something external, and good is the formal object of the will, so much so that we cannot desire evil except in so far as it appears good. The intellect, too, cannot be conceived except in relation to a formal object, and if the intellect is a faculty distinct from the senses or the consciousness, its formal object must also be different. That its formal object is the result of a greater penetration

St. Thomas in the IIa IIae, q. 8, a. 1, writes: "Dicitur intelligere, quasi intus legere." Sensitive cognition is concerned about sensible external qualities. Intellectual cognition penetrates to the essence of a thing.


than that of any of the senses is clear from the very meaning of the word intellect (from intus legere), which implies a reading of what is within. Now for the intellect and the object to be in due proportion to each other, the latter must be formally intelligible, since formal sensibility will not suffice. What the intellect immediately perceives as its formal object, without any process of reasoning, is intelligible being, of which the phenomena are but the external manifestation. We cannot conceive of intellect apart from a relation to intelligible being, no more than we can conceive of sensation without a relation to sensible phenomena, or of sight without relation to color. And just as nothing is visible except by color, so nothing is intelligible in any of the three operations of the mind (conception, judgment, and reasoning), except in so far as it has a relation to being.

Thus the study of the three operations of the mind shows us a posteriori what we have already seen a priori, namely, that the intellect is not in itself intelligible except as a living relation to being, which is the center of all its ideas, the "soul" of all its judgments and all its conclusions. Thus the intellect appears more and more as the "faculty of being," whereas the external and internal senses stop short at phenomena which constitute the fringe of reality. On this point St. Thomas remarks: "Just as the sense of sight naturally perceives color, and the sense of hearing sound, so the intellect naturally perceives being and all that which directly pertains to being, considered as such, and on this cognition is founded the perception of first principles, e.g., that there can be no affirmation and denial of the same thing at the same time and in the same sense, etc. Only these principles, therefore, does the intellect know naturally, and by their means, it perceives the conclusions, just as sight, by means of color, perceives not only all those sensible objects susceptible of perception by more than one of the sensitive faculties, but also what may be inferred from such perception." (See C. Gentes, Bk. II, c. 83, § 32).

b) Primary ideas. The first operation of the mind, which is called conception or simple apprehension, directly perceives the truths expressed by primary ideas. A vindication of the ontological validity of these ideas implies that by means of them we can come to know not only sensible phenomena, but also the being which they contain, just as written or oral words contain an intelligible meaning. It is sufficient for our purpose to show that there is something which essentially differentiates these intellectual ideas from imaginative and sensitive representations, which latter are but the direct expression of phenomena.

Our argument may be summed up in the following syllogism, which is not demonstrative, but merely explanatory:

Ideas which express not sensible qualities, but something which is in itself intelligible and accidentally sensible (sensibile per accidens et intelligibile per se), have not only phenomenal, but likewise ontological validity.

Now, the primary ideas of being—essence, unity, truth, goodness, substance, causality, finality—do not express sensible qualities, but something which is in itself intelligible and accidentally sensible.

Therefore, these primary ideas possess a validity which is not only phenomenal, but likewise ontological.

The major of this explanatory syllogism is evident from its very terms. By ontological validity is meant the aptitude to manifest the being which lies beyond or beneath the sensible or phenomenal qualities. This validity must, therefore, belong to those ideas which express, not sensible qualities (sensibile per se), such as color, sound, heat, etc., but something more profound, which in itself or directly can be perceived only by the intellect, and not by the senses (intelligibile per se). This intelligible object is sensible only per accidens.

St. Thomas (De Anima, Bk. II, Lect. 13) writes: "It must be known, therefore, that for anything to be sensible per accident (accidentally), the first requisite is, that the quality must be perceived by the sentient being; if what is accidentally sensible should not be perceived as such, it could not be said to be perceived as something accidental. It must therefore be known directly (per se) by some other cognitive faculty of the sentient being. . . . What, therefore, does not belong to any of the senses as its appropriate object of cognition, if it be something universal, pertains to intellectual apprehension. Yet, not everything which is possible of intellectual apprehension in a sensible object can be said to be accidentally sensible (sensibile per accidens), but only that which is immediately perceived by the intellect when confronted with the sensible object. We have an example of this in the fact that the moment anyone is seen speaking or moving, by the intellect one perceives that there is life in such actions and hence one can say that one sees that someone is living."


It is because of the phenomena associated with the intelligible object, and which declare its presence to the intellect at the very moment when sensation is experienced, and this without any process of reasoning, that we say that the intelligible object is only accidentally sensible (sensibile per accidens).

The minor of our syllogism presents no difficulty. The primary ideas of being—essence, existence, unity, truth, goodness, substance, efficient causality, finality, etc., do not express phenomena or sensible qualities, but something which is per se or directly intelligible and accidentally sensible.

This is immediately evident from the notion of being, which does not appeal directly to the senses, as color or sound does, but is something profounder and more universal. No simple sensible image, not even a composite one, to which a name is assigned, is an expression of being, even though the Empiric Nominalists say that it is. This image can never be anything else but a representation of phenomena in juxtaposition, and not of their intimate raison d'être. This intimate raison d’être is not something which has extension, color, heat, or cold; it implies nothing material, but itself imparts intelligibility to the various sensible elements, and is the luminous centre of every idea. Thus, the composite image with a common name, which the parrot has of a clock, differs essentially from the idea of this clock, for it is the idea alone which expresses the rationale of the movement of the clock, and tells us what the clock is, instead of merely manifesting its sensible phenomena in juxtaposition.

Being does not per se appeal to the senses, but to the intellect, and is the source of intelligibility. In addition it is accidentally sensible, because it is immediately apprehended by the intellect whenever a sensible object is presented to this faculty. It is at once perceived by it, as color is perceived by the sense of sight, and sound by that of hearing.

If the subjectivistic Conceptualists after the manner of Kant object that being, though it directly belongs to the intelligible and not to the sensible order, is perhaps but a subjective form of the mind, we answer by showing the opposition between the idea of being and those other ideas which express only imaginary beings that can exist nowhere but in the mind, i.e., are capable of conception, but not of realization, as, for example, the logical notions of universality, species, predicate, etc. Or again, to present this same truth in a clearer light, we have only to contrast the ontological formula with the logical principle of contradiction. The ontological formula states that "a being, viewed under the same aspect, cannot at the same time exist and not exist." The logical formulation of the same principle is "that we cannot affirm and deny the same predicate of the same subject under the same aspect." This latter formula merely declares the inconceivability of the absurd, whereas the former states that the absurd is objectively impossible. To seek to reduce the idea of being to a subjective form of the mind, and the principle of contradiction to a purely logical law having no ontological value, is tantamount to identifying two manifestly distinct ideas: the impossible (or unrealizable) and the inconceivable; or at least, it means that we do not dare to affirm the latter and doubt the extra-mental impossibility of the absurd. He who would doubt the ontological validity of the idea of being and of the principle of contradiction would have to maintain that a square circle is inconceivable, but not, perhaps, unrealizable outside of the mind. We have seen in the indirect defence that this doubt is absurd, even subjectively, and impossible.

The ontological or ultra-phenomenal validity of the ideas of unity, truth, goodness, substance, efficient causality, and finality, can be directly defended by referring them back to being as different modes thereof. We will discuss this point but briefly here, but later on shall demonstrate in particular the necessity and ontological validity of each of the principles founded on these ideas.

It is clear that unity, truth, and goodness are directly connected with being as properties thereof. Unity is undivided being (Ia, q. 11, a. 1). Truth is the conformity of being with the intellect upon which it depends, or the conformity of the intellect with being of which it is the measure (Ia, q. 16, a. 1-3). Goodness is desirable being (Ia, q. 5, a. 1—2). These ideas, therefore, do not express sensible phenomena, but something more profound, which is intelligible in itself, and do not, like being, imply anything material in their formal signification.

It is the same with the idea of substance, which is but a determination of the idea of being. Substance is being capable of existing in itself and not in something else. The intellect, which at once perceives being underneath the phenomena (something which is), observes that these phenomena are many and variable, while being, on the contrary, is one and the same, and that it exists in itself, and not as an attribute in another. Being considered as such is called substance.

Efficient causality is nothing else but the realization or actualization of something which did not previously exist. It is clear that this realization, defined in terms of its immediate relation to potential and actual being, is perceived by the intellect, the faculty of being, under the appearances of color, heat, etc., which are perceived by the senses.

Finality is nothing else but the raison d'être, the why and wherefore of the means. The intellect immediately apprehends the purpose of the eye, made for seeing, and that of the ear, made for hearing; but the senses cannot perceive this why and wherefore.

Thus the ontological validity of these primary ideas is explained and can be directly demonstrated by the fact that they denote the very opposite of what is implied by the sensible elements or phenomena.

Thus, too, we see that the true solution of the problem of universals is to be found only in moderate Realism. Empirical Nominalism abolishes the intellect and intelligibility. Subjectivistic Conceptualism reduces our intellectual life to a coherent dream. Moderate Realism, on the other hand, as formulated by Aristotle, St. Thomas, and the traditional philosophy of the Schools, safeguards our intellectual life and its real validity, without admitting the exaggerated Realism of Plato, Spinoza, and the Ontologists, who claim to possess, without abstraction, an intuitive knowledge of purely intelligible realities, and who, in various degrees, confuse universal being in sensible things with the divine being. We shall return to this subject when we discuss the principle of substance, and in refuting Pantheism, which is the logical outcome of this exaggerated Realism.

Various reasons make it clear that absolute realism involves an intrinsic contradiction. Since those who adopt this theory consider the concept of being to be univocal, they cannot explain the appearance of various modes of being, and, with Parmenides, must deny all multiplicity. They are prompted, as Spinoza was, to make of finite substances and their faculties simple verbal entities. This theory ends in Nominalism, which it originally repudiated, and paves the way for Phenomenalism, which declares that there is but one substance, and in it a succession of phenomena or modes.


From our previous remarks about the idea of being and the other primary ideas, we see, in contrast with Nominalism, that there is a fundamental difference between the image and the idea. The idea, in matter of fact, differs from the image because it contains the raison d'être of the object which it represents (quod quid est, seu ratio intima proprietatum), whilst the common image of the Nominalists, to which a common name is assigned, contains only the external notes of the object in juxtaposition, revealing them to us without rendering them intelligible. The idea and the image are often contrasted by saying that the idea is abstract and universal, while the image is concrete and particular. In case of a composite image with a common name, the contrast between it and the idea is not so pronounced. Moreover, the character of abstraction is merely a property of the idea, and even a property of the human idea, qua human, derived from sensible data. Universality is also but a property of the idea, and does not designate its essence. Whether we consider the human, the angelic or the divine idea, the essence of the idea, qua idea, is that it contains the formal object of the intellect, qua intellect, that is to say, being, or the raison d'être.

An example cited by Vacant in his Etudes Comparées sur la Philosophie de St. Thomas d'Aquin et celle de Scot (Vol. I, p. 134) will help us to understand what is meant by the intuition of the intelligible in the most rudimentary kind of intellectual knowledge. "Place a savage in the presence of a locomotive," he writes; "have him walk around it, and give him time to examine it and other similar machines. So long as he only sees them running, and is content to observe the various parts of their mechanism, he will have but a sensible and particular knowledge of them (or, if you wish, a common image, accompanied by a name, just as a parrot would have). But if he is intelligent, he will sooner or later come to realize that there must be in such an object a motive power, which the locomotive either generates or applies. . . . If he finally learns that it is by the expansion of the imprisoned vapor that this motive power is obtained, he will understand what a locomotive is (quod quid est) and will form a specific concept thereof. . . . The senses perceive only its material elements, a black mass of iron, with a special arrangement of parts. The idea represents something immaterial; it gives the why and wherefore of this arrangement and of the functioning of the various parts. Consequently, the idea becomes stamped with the mark of necessity, and by it we see that every locomotive must move, granted the conditions for which previously we could find no reason. The idea, finally, is universal, and by means of it we understand that all machines thus constructed have the same power and attain the same end."

The common image of the locomotive contained merely the common sensible elements in a state of juxtaposition, and did not explain their raison d'être nor render them intelligible.

This is what is generally understood by abstractive intuition of the intelligible element or the raison d'être of an object. Let us now take an example from rational psychology, say, the idea of man. This idea is something more than a merely mechanical juxtaposition and association of common traits possessed by all human beings, such as those of rationality, freedom, morality, religion, sociability, etc. It also renders all these traits intelligible, by showing that the first of them, rationality, is the raison d'être of all the rest; it expresses what man is (quod quid est). That which constitutes man truly a man, is not liberty, or morality, or religion, or sociability, or even the power of speech, but reason; for from reason all the other traits are deduced. The ability to reason becomes intelligible when the fact is established that the raison d'être of the three operations of the mind (simple apprehension, judgment, and reasoning) is an essential relation between the intellect and being, which is its formal object.

In truth, we must admit that the Nominalists are right in maintaining that there are but few ideas susceptible of becoming fully intelligible, namely, those which can be referred to being, which is the primary objective light of man's intellectual cognitions. These ideas are principally those which belong to what Aristotle (Met., Bk. X, c. iii) calls the third degree of abstraction, i.e., abstraction from all matter; they appertain to the metaphysical, spiritual, and moral order (ideas of being, unity, truth, goodness; the idea of intellect, defined in terms of its relation to being; the idea of will, defined in terms of its relation to goodness. In this class must also be included the ideas of the primary divisions of being, such as potency and act, and the four causes). In the second degree of abstraction (mathematical abstraction, which is concerned, not with sensible qualities, but only with quantity, continuous or discrete), the intelligibility is less, although the study of these sciences comes easier to man, because their object is less abstract and nearer to the senses. Finally, in the first degree of abstraction, we have the natural sciences, which are concerned with sensible qualities, merely abstracting from individual circumstances; here we can give empirical and descriptive definitions, but we can never come to know the intelligible properties of an object, explaining their raison d'être by a specific difference. Most of the time we have to be satisfied with a statement of general facts, and the low degree of intelligibility found in these sciences—as we have just seen in the case of the savage and the locomotive—arises from the application of the metaphysical principles of causality and finality, which the intellect spontaneously perceives in being.

Such, then, is the abstractive intuition of the intelligible in the first operation of the mind, which is denied by the Sensualists and the subjectivistic Idealists.

c) Confirmation: "Being" occupies the first place in the two processes of judgment and reasoning. In the second operation of the mind, that of judgment, we also see the falsity of these two systems and the truth of traditional Realism. What radically differentiates judgment from the association of ideas by which the Empirics seek to explain this mental process, is that this association is merely a mechanical juxtaposition of two images, whereas judgment by the verb "is" affirms the real identity of the subject with the predicate of a proposition, which are but logically distinct. The verb "is" constitutes the very soul of every judgment. As Aristotle remarks (Met., Bk. V, c. vii), "there is no difference between these two propositions: ‘this man is in good health,' and ‘this man is healthy'; nor between these: ‘this man is walking, advancing on the road,' and ‘this man walks, advances on the road'; the same is true of the other cases." By using the copula "is" we affirm that the being called man is (i.e., is the same as) the being that is in good health. Empiricism is sufficiently refuted by this simple observation. As J. J. Rousseau remarked, "the distinctive sign of an intelligent being is the ability to give a meaning to this little word is, which he utters every time he pronounces a judgment.

At the same time we perceive the falsity of the subjectivistic Rationalism of Kant, as proved by Msgr. Sentroul in his thesis, "L'objet de la Métaphysique selon Kant et Aristote" (Louvain, 1905, a work crowned by the Kantgesellchaft of Halle). "Kant, maintaining the very opposite of what Aristotle taught," says this writer, "failed to realize that all knowledge expresses itself exactly in the verb to be, the copula of every judgment, . . . that the union of the predicate with the subject by means of the verb to be, used as the sign of identity between the terms, constitutes the formal essence of every judgment. . . . The knowledge of anything consists precisely in perceiving its identity with itself from two different points of view. (Met., Bk. v, c. vii). To know what a triangle is, means to know that it is a certain figure, the cause, to know that the effect is included in it, the man, to know that he is endowed with the power of imagination. And to take a purely accidental judgment, to say of some particular wall that it is white, is to say of this wall that it is a white wall. . . . If the subject and the predicate refer to each other in such a way that they can be connected by the verb to be, this is because both predicate and subject express one and the same reality (either possible or actual)." Kant acknowledges identity only in what he calls analytical judgments, pure tautologies in his opinion, and not in extended judgments, which alone add to the sum of human knowledge and which he calls synthetical a priori or a posteriori, because they are formed, according to his view, by the juxtaposition of distinct notions. He thus misunderstood the fundamental law of all judgment. Msgr. Sentroul (p. 224) truly remarks that "a judgment formed by the juxtaposition or the convergence of various notions would be a false judgment, since it would express identity between two terms which are not identical, but merely related to each other in some other way. . . . Aristotle's principle of distinction between propositions is not the identification or non-identification of the predicate with the subject: he distinguishes them according as the knowledge of this identity (not logical, but real) is derived solely from the analysis of the ideas or from the scrutiny of existing things." Like the sophists of old, Kant must maintain that we have no right to say, "the man is good," but only, "the man is the man, the good is the good;" but this amounts to a denial of the possibility of any judgment whatever. (Cfr. Plato, Sophist., 251 B.; Aristotle, Met., Bk. V, c. 29). The reason of this opposition between Kant and the traditional philosophy is that Kant, starting with the subject, considers the categories as purely logical, whereas Scholastic philosophy, which starts from being, regards the categories as partly logical and partly ontological. What was separated by abstraction from the real is thus reconstructed and restored to it by the affirmative judgment, and the entire life of the intellect can be explained by its ordination to being.

As for the necessity of starting from being, we have already seen that it is mandatory, under pain of rendering absurd all the elements—the object, the idea, the act of thinking and the intellectual faculty of knowledge.

The third operation of the mind, that of syllogistic reasoning, like the two preceding ones, cannot be anything else but the act of a faculty which has being as its formal object. Whereas empirical findings, governed as they are by the laws of the association of ideas, are but a series of images in juxtaposition, reasoning gives us the (extrinsic) raison d'être of the less known in that which is known more explicitly. The demonstration a priori gives us the extrinsic reason of what has been affirmed by the conclusion. The demonstration a posteriori gives us the extrinsic reason why something has been affirmed. Direct or ostensive demonstrations are founded on the principle of identity, which is immediately implied in the idea of being (the syllogistic process is based upon the principle that two things equal to the same third thing [middle term] are equal to each other). Indirect demonstrations, also known as reductio ad absurdum, rest on the principle of contradiction, which is merely a negative formulation of the principle of identity. Inductive reasoning rests on the principle of induction, which is a derivative of the principle of the raison d'être. If the same cause, in the same circumstances, did not produce the same effect, the change in the effect, without a previous change in the cause or the circumstances, would be without a sufficient reason for its existence. For the Empiric, who reduces the concept to a common image with a common name, the syllogism must be a needless repetition, as Sextus Empiricus, John Stuart Mill, and Herbert Spencer held. Since the major is not a universal statement, but merely expresses a congeries of individual cases, it presupposes that all the particular cases, including the one mentioned in the conclusion, have been verified. From this point of view any rational proof of the existence of God is evidently impossible, nor can there be any truly scientific knowledge even of sensible things, because induction no longer has any foundation in fact.

See Lachelier, Le Fondement de l’Induction.


Finally, the first principles which constitute the basis of all reasoning, are immediately perceived in being, which is the primary object of abstractive intuition on the part of the intellect. "The intellect naturally knows being, and all which directly pertains to being, considered as such, and the knowledge of first principles has its foundation in this cognition of being." (St. Thomas, C. Gentes, Bk. II, c. 83, § 32). A child does not need to be taught the principles of identity, contradiction, substance, sufficient reason, causality, and finality. It seeks for the cause of everything that attracts its attention, and wearies its elders by constantly asking for the reason why. As Aristotle remarks (Anal. Post., Bk. I, c. 1), if the child had no knowledge of these principles, the teacher could not influence its mind; for all instruction assumes some previous knowledge in the pupil.


19) Objections of the Idealists: We cannot start from being; something corresponding to thought is a necessity. Reply.


1. The subjectivistic Idealist raises this objection: "You always start from being, and not from the representation of being. How can you be sure of the validity of this representation, since you cannot compare it with the object itself, as it exists outside of the mind, and since it is impossible for you to establish an immediate contact with the object?" Moreover, Le Roy maintains "that Ontological Realism is absurd and disastrous; an external something, beyond thought, is by its very nature impossible of conception. This objection will always remain unanswerable, and we shall have to conclude, as all modern philosophy does, that we are under the necessity of admitting some form of Idealism."

"Comment se pose le problème de Dieu," in the Revue de Mét. et de Mor., July, 1907, pp. 448 and 495.


This difficulty is not new, for Protagoras and other Sophists raised it centuries ago, as may be seen from the fourth Book of Aristotle's Metaphysics, where it is refuted. St. Thomas (Ia, q. 85, a. 2) reproduces this objection in the following form: "Nothing is known, except it is in the mind of the knowing subject. Now, extra-mental realities cannot be in the mind of the knowing subject. Therefore, they cannot be known; the ideas in our mind are all that we can know."

St. Thomas replies by distinguishing the major: nothing is known, except it is in the knowing subject, either by itself, or by its likeness (intentionalis)—this I concede; but if the proposition means that the object itself must be in the knowing subject, the statement is false. Now, it is evident that extra-mental realities cannot be in the mind of the knowing subject per se, but they can be there by representation. And it is the special purpose of this representation, which is essentially relative (intentionalis) to the object represented, to make known the object by a direct act of the mind, without being known itself. The representation becomes known only afterwards by means of reflection. The idea impressed upon the mind, or the idea expressed by it, are both the means by which the mind knows the object, and not the object which it knows. It is essentially what the Scholastics call "intentionalis," a term which means that it refers to what is represented by the idea; and if this idea is a simple one, like that of being and other such primary notions, it cannot be an artificially composite notion, which would misrepresent the reality.

See St. Thomas, S. Theol., Ia, q. 85, a. 6: "Whether the intellect can err." "Properly speaking," he says, "the intellect is not deceived concerning the quiddity of a thing. . . . It may, however, be accidentally deceived concerning the quiddity of composite things (on the part of the composition affecting the definition). . . . As regards simple objects not subject to composite definitions, we cannot be deceived, unless we understand nothing whatever about them, as is said in Metaph., IX, c. x."


To grasp the meaning of this reply, we must fully understand what is meant by the term representation or idea. The Idealists declare that "something external to or beyond thought is by its very definition unthinkable," because they consider the idea as an isolated object and not as a manifest relation. They find fault with traditional philosophy for considering space as belonging to the imaginative order. But from the way in which they view it as external to thought, we may say that they commit the same error. This concept of the representation is entirely quantitative and material. Though this may seem paradoxical, Idealism has a completely materialistic conception of the idea, which it regards as a material portrait, situated in some point of space and capable of being itself considered as an object, independently of the person whom it represents. It is like the effigy stamped on a coin. In direct contrast to this, the cognitive faculty (the intellect and, for that matter, even the sense), like the representation by means of which it knows the object, is a living and immaterial quality, not something closed, shut up within itself, but essentially relative to something other than itself, which it represents to itself. This function belongs to it by its very nature (quid proprium). Therefore, far from a something beyond thought being unthinkable, thought is not intelligible except as a living relation to something external, which it expresses. We could not possibly judge of the validity of the idea, if it were in the direct act, as a material portrait, the very object of knowledge: for in that case we should have to compare this interior object with an intangible external object. In matter of fact, however, the idea in the direct act of knowing is not the object of knowledge, after the manner of a picture or a statue. It is only the means by which the object is known.

Dunan, in his work entitled, The Two Idealisms (Alcan), has clearly set forth this traditional conception.


Because it is a vital, immaterial quality, entirely relative to something other than itself, it reveals the presence of things without being itself revealed. Afterwards, by means of reflection, the intellect assures itself of the validity of this means, of its conformity with the extra-mental object, because, as St. Thomas remarks,

"Truth is in the intellect, as following the act of intellection, and as what is known by the intellect. It follows the operation of the intellect in that the judgment of the intellect deals with the quiddity of the thing. By reflecting upon its act, the intellect knows not only its own act, but also that its cognition is in conformity with the object of cognition. And this can be so only because it knows the nature of its own act, which it cannot know unless it knows the nature of its active principle, namely, the intellect itself, which by its very nature postulates conformity with the object. Therefore, the intellect knows the truth by the very fact that it reflects upon itself." (De Veritate, q. 1, a. 9; cfr. also q. 2, a. 2).


"the intellect knows its ideas and its own direct act by reflection, and it not only knows, like the senses, the fact of its own activity, but also the nature of its act, and hence its own nature as an intellective faculty, which is that it is essentially relative and in conformity with being." It sees that if complex ideas can accidentally imply an error in uniting elements incompatible with the reality, such cannot be the case with primary ideas on account of their simplicity.

In its ultimate analysis this doctrine implies that the immateriality of the representation is the principle of its power of representation. "Cognoscens secundum quod cognoscens differt a non cognoscentibus prout fit aliud in quantum aliud; et hoc immaterialitatem supponit" ("by the mere fact that a being knows, it differs from those who do not know, in that it becomes some other thing, in as much as it has the form of that other thing; and this presupposes immateriality") (St. Thomas, Summa Theol., Ia, q. 14, a. 1). Like Aristotle (De Anima, Bk. II, c. xii; Bk. III, c. viii) the Angelic Doctor considers it to be a fact that the animal, by reason of sensation, in a certain way becomes the other beings which it sees and hears, whereas the plant is shut up within itself. And, far from denying this fact, under the pretext that something external to or beyond thought is an impossibility, he explains it by the immateriality of the cognitive faculty. Why is it that the animal, by its senses, responds to everything in the sensitive order, and, so to speak, goes out of itself, beyond the limits of its corporeity? This sortie would be inexplicable if it were of the spatial order; but, on the contrary, it presupposes a certain independence with regard to extended matter, that is to say, a certain spirituality. The representation in the irrational animal is of an order superior to the material bodies which it represents, because it is the act of an animated organ (and not of the soul alone), it can be born of the impression gained from these material things. It is a quality essentially relative to them, somewhat like the reflection of an object formed in a mirror, with this difference, that the eye is a living mirror which sees. Being by its very nature essentially relative or intentional, the representation cannot be that which is known first, but in the direct act it makes known the object which it represents without being known itself (non est quod cognoscitur, sed quo) . It is not something closed, but openly in contact with the object to which it essentially refers, and thus leads us immediately to the object and determines the cognitive faculty to know the same, like a fire started in a grate, which essentially refers to the luminous object or to the source of the heat which it produces.

What has already been realized in the simple form of sensible cognition in the animal, namely, the spontaneous transition from the ego to the non-ego (even to the imaginary non-ego), cannot be explained in any other way. To say that all sensation has a tendency to become objective, similar to that which we notice in the case of hallucination, is to explain a primitive fact by a derived fact. Every hallucination presupposes anterior sensations; one born blind never has visual hallucinations. "One might just as well explain the sound by the echo."

Moreover, this tendency towards objectivation would still be but a fact which must be made intelligible. The reason why we do not objectivate our emotions, but only our sensations, is because the latter alone are essentially intentional or representative.

St. Thomas, De Anima, Bk. III, Lect. 8; Ia, q. 85, a. 2, c, ad 1um et ad 2um.


Finally, as the contemporary English Neorealists point out, if Idealism is true, then cerebral perception is just as subjective as that of the external universe, and consequently the brain no longer acts as an intermediary which separates sensation from its objects, and prevents it from coming in contact with them. Directly the external universe is perceived, either the cerebral phenomenon is real, though not perceived, which is contrary to the accepted principle of Idealism, "esse est percipi"; or else this cerebral phenomenon, not being perceived, is unreal, and in that case it no longer impedes the immediate external perception of the universe. Thus one of the principal arguments in defence of Idealism falls to the ground.

Cfr. McGilvary, "The Physiological Argument against Realism," in the Journal of Philosophy, Psychology, and Scientific Methods, Oct. 14, 1907.


In the case of intellectual cognition, which is purely immaterial, the transition from the ego to the non-ego is not only spontaneous, but also reflexive, and the ego and the non-ego are known precisely as such. This is in fact the very first "morcellation" (division) of being into object and subject, into absolute (entitative) and intentional being. In simple apprehension the intellect obtains a knowledge of being, of something which is, before it knows itself; for how could it know itself in a state of vacuity before it has acquired a knowledge of anything? But in this first apprehension, the intellect knows being without knowing it precisely as non-ego. Later on, the absolute spirituality of the intellect enables it to reflect fully upon itself, and thus to know not only that its act is an actual fact, but also what is the nature of that act and thereby to perceive its own immateriality as an essentially relative faculty in conformity with intelligible being. The intellect then judges being as something distinct from itself, i.e., as a non-ego. (St. Thomas, De Veritate, q. 1, a. 9 and q. 2, a. 2). This division of being into absolute and intentional must be admitted, otherwise all three operations of the intellect become meaningless.

Therefore, it is not Ontological Realism which is "absurd and disastrous," but Idealism, which is absolutely inconceivable. A representation which does not represent anything, would be at the same time and in the same respect both relative and non-relative. Idealism is as disastrous as it is absurd (cfr. no. 17); it locks up man within himself, as it were, preventing him from recognizing even the reality of his own action, and thus destroys all knowledge and reduces man to the condition of the plant, ὅμοιος ϕυτῷ; (IV Metaph., c. iv). It must be so unless it be claimed that human thought, like divine thought, is identical with being; but in that case man must be omniscient and there can be no mystery for him. (St. Thomas, Summa Theol., Ia, q. 79, a. 2). Either God or the plant—we must choose one of the two.

A close study of the first principles of knowledge makes it increasingly evident that between the traditional philosophy and Idealism, the question of paramount importance is to know whether we are at least certain of the objectivity of the principle of non-contradiction or identity.

This objectivity was subjected to unreasonable doubt by Descartes at the end of his Discours sur la Méthode.


It is evident for us that the absurd is not only unthinkable, but that it is also really impossible, or in itself impossible of realization, even for the Omnipotent Being, if such a one exists. That which is impossible of realization stands de facto in correlation to the unthinkable. Now the real impossibility of the absurd is for us an evident fact, the very first, anterior and superior to that of Descartes' "cogito.” We feel ourselves dominated and regulated by it, that is to say, by evident being, which excludes non-being or contradiction. In this first of all its acts, that of adherence to being, the created intellect manifests itself as potential and conditioned.

See P. Lepidi, O.P., Ontologia, p. 35.


This primordial evidence is a fact attested by the reason or the intellect. By what secret process this fact is established, remains for us a profound mystery, because it is an entirely immaterial process, and too dazzling a light in itself for the feeble vision of our intellect. In this life we have but indirect knowledge of the immaterial, by way of analogy with material things; and we know the properties of things only in a negative and relative sense, by saying that they are not material and that their vitality is superior to that of the senses. Hence the obscurity of all our theories of knowledge. But simply because the intrinsic nature of a thing remains for us obscure, we can neither deny the fact itself of knowledge nor give an explanation of it, which is tantamount to a denial of the same by introducing the element of contradiction into each of its component parts. It is this which Idealism does. (See no. 17). Philosophical reflection must explain this process of knowledge in harmony with the nature of things, and not in opposition to it. The theories must interpret the facts and not deny them. If the theories are obliged to assume illusions of nature, then they are illusory themselves. In proving the natural range of the intellect with regard to being, we must not deprive it of its essential relationship to being; one does not have to break a spring in order to test its strength.

About twenty-five years ago Rousselot wrote on this point:

"Métaphysique Thomiste et Critique de la Connaissance," in La Revue Néoscolastique de Philosophie, Nov. 1910, pp. 501-508.


"After having assured oneself of the evidence of being and the fact of its affirmation, it remains to give a satisfactory account of the meaning and validity of this fact. Failure to see or to accept this duty would be to finish too soon with philosophy and to mutilate it. . . . To be sure, this explanation can be given only by the application of some system of metaphysics. Now, if it is given by means of the metaphysics which starts from the 'philosophy of being' and which satisfies dogmatic reason before any critical question arises, the problem is solved." On his part Rousselot believes that we must explain our first affirmation of being (that being exists or that the reality is intelligible being) by saying that this affirmation "marks the transition to the act expressive of that desire for the divine known as intellection;" and he adds that, according to St. Thomas, "it is God who first arouses the rational appetite of a creature to action." (Ibid., p. 505).

We never claimed that our first affirmation of being did not need to be explained; and it is clear that it can be explained by means of the four causes. On the contrary, we have always explained it

See Le Sens Commun et la Philosophie de l'Être, p. 100; Dictionnaire Apologétique, article "Dieu," cols. 1002 and 1003.


by actual immateriality of the intellect, which by reflection can know not only the fact of its own activity, but the very nature of its act, and of this act towards its own self, which essentially refers to being. We have elucidated this point by giving in substance the argument of St. Thomas in De Veritate, q. 1, a. 9, and q. 2, a. 2. We admit then, with Rousselot, that the certitude of the objectivity of our knowledge has its foundation not only in a formulated principle, such as that of contradiction, but also in the knowledge which the mind has of its own nature whenever it reflects upon its actions. Criticism must try to grasp the full meaning and range of this act of reflection.

After that, we may consider ourselves as having passed not only beyond the stage of spontaneous discovery of being and its principles (in via inventionis), but also beyond that of critical reflection, and to be in possession of those ontological principles by which the ultimate reasons of things are made known. The reason or ultimate cause of our certitude may then be discovered a posteriori, and thus the point of departure of the argument for the existence of a prime intellectual mover will be the fact that our intellect is itself moved whenever it is in action. (Sec further on, no. 36, c). We may also suppose this supreme cause to be already known and by means of it give an a priori explanation of the objectivity of our knowledge.

See St. Thomas, Summa Theol., Ia, q. 79, a. 8: "Whether reason is distinct from the intellect. Human reason, by way of seeking and finding, advances from certain things simply understood, which are the first principles. And again, by way of judgment it returns analytically to first principles, in the light of which it examines what it has found" (critical reflection). In the following article St. Thomas discusses another via judicii, not critical, but strictly metaphysical, and by this other method of judgment everything is judged from a higher point of view by God Himself, who is now actually known: "By way of finding, we come through knowledge of temporal things to that of things eternal. . . . By way of judgment, from eternal things already known, we judge of temporal things."


In this ontological order of the ultimate reasons of things, we must say that the supreme foundation of the certitude that our intellect has concerning the objectivity of first principles is to be found in God, inasmuch as our intellect is a participated likeness of the Divine Intellect, which is absolutely identical with Being itself. Though St. Thomas rejects Platonism and the theory of the Ontologists that necessary and eternal truths are intuitively known by us in God, he admits that, in this life, God is in a certain sense the source of our knowledge, in that the natural light of our intellect is a participated likeness of the divine and uncreated light, and that, in order to operate, the intellect needs to be illumined by the self-same intelligent and subsistent Being. "The intellectual light which is in us," he says, "is nothing else but a certain participated likeness of the uncreated light, in which are contained the eternal types." (Ia, q. 84, a. 5). Elsewhere he writes that "there must needs be some higher intellect, by which the soul is helped to understand." (Ia, q. 79, a. 4). This illuminative divine concurrence is required not only for the first act of our intellect, but for all its acts?

St. Thomas clearly distinguishes between this divine concurrence and supernatural grace in the Ia IIae, q. 109, a. 1: "Whether without grace man can know any truth." We read there: "Hence we must say that for the knowledge of any truth whatsoever, man needs the divine help, so that the intellect may be moved to its act. But he does not need a new light added to his natural light, in order to know the truth in all things, but only in some that surpass his natural knowledge." (See Gonet, Clypeus Thomisticus de Gratia, tr. VIII, disp. 1, a. 1.)


Pure intellect, containing no imperfection, is identical with pure being; but an intellect that is imperfect cannot be identified with imperfect being as its proper object; for otherwise it would no longer be an intellect at all. And the intellect cannot attain to such being except by the illuminating guidance of that First Intellect, who is the self-subsistent and intelligent Being. This is the ultimate reason assigned by metaphysics to our primary affirmation of being. But this explanation presupposes (quoad nos) the proofs for the existence of God, and cannot, therefore, be adduced as their principle; it merely confirms them by giving the fundamental ontological and ultimate cause of our certitude.

Rousselot goes even farther. "If the soul responds sympathetically to being as such," he says, "the final reason for this is because the soul is capable of communing with God" (l. c., p. 504). The affirmation of being "marks the transition to the act expressive of the desire for the divine known as intellection" (p. 505). This explanation, which reminds us in certain respects of that given by Rosmini, in our opinion is wrong, in that it defines the intellect not in its relation to being, but in its relation to the divine.

On this point see the article by Fr. Gardeil, O.P., in the Revue Néo-scolastique, Nov., 1910, pp. 504 ff., entitled "Faculté du Divin ou Faculté de l'Être." See also Revue Thomiste, 1913, pp. 460-472. Likewise Chronique de Métaphysique by Fr. Le Rohellec, C.S.S.P.


As a matter of fact, the intellect and being are two correlative analogues; only the divine intellect refers directly to divine being, with which it is identical; the created intellect refers to created being,

Created being is the proper or proportionate object of the human intellect. God, as He is in Himself, is included only in the adequate object of the human intellect: for it is not within the scope nor is it the natural bent of the created intellect to know God as He is in Himself, unless reinforced by the essentially supernatural light of faith. Previous to the reception of this supernatural light there is in our intellect but an obediential potency or passive capacity of being raised to the supernatural order. John of St. Thomas (in Iam, q. 12, disp. XIV, a. 2, no. II) points out why the Thomists could not admit, with Suarez, the existence of an active obediential potency. It would be essentially natural, by reason of its being a natural property of the intellect, and also essentially supernatural, in that the intellect would be specified by a supernatural object. This would virtually mean that the natural and the supernatural order are not essentially and necessarily distinct, but only actually so. (See also Billuart in Iam, q. 12, diss. IV, a. 5, § III).


and comes to know God by this means. Moreover, that the intellect knows of the certitude it has acquired, in which intellection more specifically consists, Rousselot attributes to its natural inclination (appetitus naturalis), a characteristic of the will and of every other faculty.

"Certainty is always found in one of two ways, either essentially or by participation. The certitude of the cognitive faculty undoubtedly is essential. But it is found by participation in everything which is infallibly moved to its end by the cognitive faculty. When it is said that nature operates with certainty, in that it is moved by the Divine Intellect, since everything is moved with certainty to its end by this Intellect, it is certainty by way of participation that is meant." (See 2a 2ae, q. 18, a. 4, De Certitudine Spei).


That which belongs to a species as its property cannot be explained by what is common to all species of the same genus. In fact, the certitude of our primary affirmation of being is explained by the objective evidence of being, and by the very nature of our intellect when influenced by the divine, the former being a participated likeness of subsistent intellection, which includes in its embrace both the subsistent Being and all possible beings of which the Supreme Being is the exemplar. God has a pure and absolutely immediate intuition of purely intelligible Being; our human intellect abstracts the intelligible from its sensible surroundings, and hence has an abstractive intuition of the intelligible.

2) Second objection of the Idealists. Because thought is immaterial, a new difficulty presents itself. The intelligible known by our intellect is not real unless it is found in the things themselves. But how can it be found in the sensible things from which it is said to be abstracted, since it is not contained in them? As there can be nothing actually intelligible, immaterial, and universal in sensible things, the intelligible, the object of our intellectual cognition, is not real.

This is the classical objection against the solution given by Traditional Realism to the problem of universals. St. Thomas foresaw and solved it in his Summa (Ia, q. 85, a. 2, ad 2um). That the intelligible, he says, cannot be present in material things in the abstract, immaterial, and universal mode in which it is found in the mind, I concede; that it cannot be there without this mode on account of its nature or essence known by the intellect, I deny. "In speaking of the intelligible, the universal, the abstract, we imply one of two things—the nature of the thing known, and its actual intelligibility, universality or abstraction. Nature, e.g., humanity which is intellectually understood, abstracted or considered as universal, exists only in individuals, while that mode which is actual intelligibility, universality, abstraction, exists only in the intellect. We have something similar to this in the senses. For sight perceives the color of the apple apart from the smell. If it be asked, where is the color which is seen apart from the smell, the answer is: in the apple. But that the color is perceived without the smell, is owing to the sight, since the faculty of sight receives the likeness of color and not of smell."

For an explanation of this passage, which contains a refutation of the Kantian objections, see Zigliara, Summa Philosophica, Vol. I; Ontologia, Bk. 1, c. 1, articles 3 and 6.


3) Third objection. Our concepts cannot express as universal what the senses perceive as singular. Now, the senses perceive only sensible phenomena. Therefore, our concepts are valid merely as representative of phenomena.

The answer to this objection is included in what has been said above in connection with Idealism. Our concepts cannot represent as universal what our senses perceive as individual, whether what is perceived be directly or only accidentally sensible. That the senses perceive only sensible phenomena, which do not constitute the direct and proper object of the sensitive faculties, is true. But it is not true that the senses do not perceive the subject of phenomena, being and substance, even accidentally. It is not color in general that is perceived by the sense of sight, but a colored object, inasmuch as it is colored; the intellect, on the other hand, perceives being and substance in the object, it reads in the phenomena (intus legit), at least indistinctly, the principle of their intelligibility, the essence of which they are the property (Cf. St. Thomas, De Anima, Bk. II, Lect. 13; Summa Theol., Ia, q. 17, a. 2; q. 78, a. 3, ad 2um).

4. Fourth Objection. After all, the ontological validity of first ideas and first principles depends upon the validity of sensation. Now, the knowledge acquired by the senses cannot have metaphysical, but only physical certainty, derived from experience. Therefore, we cannot be metaphysically certain of the ontological validity of first ideas and first principles.

Reply. The ontological validity of first ideas and first principles depends upon the validity of sensation—not as if this latter were the real reason in some formal and intrinsic manner of that ontological validity; the dependence must be interpreted as meaning that sensation in some material and extrinsic way is a predisposing cause and a required condition. The real reason for the certainty of this ontological validity is not the evidence obtained from sense experience, but belongs to the intellectual order, and is a vision of the intellect, not of the senses. For this reason the certitude is metaphysical and superior to that acquired by the senses. As St. Thomas remarks: "It cannot be said that sensible knowledge is the total and perfect cause of intellectual knowledge, but rather that it is in a way the material cause. . . . We must not expect the entire truth from the senses. For the light of the active intellect (intellectus agens) is needed, through which we achieve the unchangeable truth of changeable things and discern the things themselves from their likenesses." (Ia, q. 84, a. 6, ad 1um). "All the certitude of the knowledge that we have depends upon the certitude of the principles . . . and therefore, that anything is known for certain is due to the fact that man has been divinely endowed with that interior light of reason by which God speaks in us," (St. Thomas, De Veritate, q. 11, a. 1, ad 13 et 17um). The intellect, by the light that is in it, and by means of its own principles, judges of the validity of sensation, of which it makes use.

What is a cause in one order becomes an effect in another order; but the formal cause is absolutely prior to the material cause. Our intellection presupposes sensation in the material order, but formally it passes judgment on sensation.


Intelligible being and its opposition to not-being are known by the human intellect before it judges of the validity of sensation, nay, even before abstraction is assigned as the reason of this knowledge. Then, by means of the light of being and certain first principles, it judges of the validity of sensation and of abstraction. It is in this way that philosophical reason is able to proceed in the critical discussion of metaphysical questions, as Aristotle did. (See Metaph., Bk. IV). It can defend the ontological validity of the notion of being and of the principle of contradiction, by a simple analysis of the terms: intellect and idea. This it is able to do even before it solves the problem of the origin of ideas. Hence a number of contemporary Scholastics, such as Zigliara, in their refutation of Scepticism solved the criteriological problem before they considered the question of the origin of ideas, which was assigned by them to rational psychology. A sensation which is the record of no sense perception would be contrary to the principle of contradiction; a sensation which is not the effect of a determining external cause would be contrary to the principle of causality. If the purpose of the senses as such is not to know the realities of sense perception, then they are contrary to the principle of finality. It may happen that the senses are deceived, even as regards their proper object, but this is due to some organic defect. (See Ia, q. 17, a. 2). On the other hand, the intellect can never be deceived concerning primary and simple ideas and first principles. (Ia, q. 17, a. 3, c., and ad 2um). The natural certitude of these principles persists in spite of the systematic errors by which they are deprived of their original meaning, or even denied. These errors are like a cloud of the imagination on the fringe of the intellect, and they cannot succeed in penetrating the faculty so as to change it completely; for that would mean the complete destruction of reason itself. "We do not always have to think as we speak," was Aristotle's remark to those who denied the principle of contradiction. (IV Met., c. iii).

Thus all our explanations eventually lead us back to those primary ideas and first principles, and to the intellectual light which reveals them to us. The object of these ideas and principles is evident, since it is being itself, which is evident. With regard to the intellectual light, it makes known everything to us, but in this life we do not know it as it actually is, namely, in its pure immateriality. When we wish to tell what it is, we are obliged to describe it by analogy, in terms applicable to material light and its effects; when we wish to state in what it formally consists, we make use of negative and relative terms, by saying that it is a non-material light and a vivid light, emanating from a faculty superior in vitality to that of the senses. We describe this light by means of a sensible image, since it is too brilliant for us to perceive in its pure immateriality. In this life our intellect, functioning as it does in connection with the senses, when confronted with this light, resembles an owl looking at the sun; for it is only by reason of the reflection of this light in sensible things that the intellect sees it, making known its dormant intelligibility.

St. Thomas, Ia, q. 87, a. 1, 2, 3: "The human intellect is merely a potentiality in the genus of intelligible things, just as primary matter is a potentiality as regards sensible things; and hence it is called possible. Therefore, in its essence, the human mind is potentially understanding. Hence it has in itself the power to understand, but not to be understood, except as it is made actual. . . . And it is made actual by the species abstracted from sensible things. . . ." (Ia, q. 87, a. 1). Cajetan comments on this passage as follows: "Because the active intellect does not actuate the passive intellect directly as its object, but through the medium of the denaturalized intelligible species, to which its act is first of all directed, it follows that it cannot come to know itself by any reflective process, but requires the intervention of some object as its medium." (Ib., n. XV.)


The fact that we are incapable of acquiring a direct and precise knowledge of the immaterial nature of our intellectual faculty, is the reason why, in this life, there will always be an element of obscurity in every theory of knowledge, no matter how true it may be. But because this obscurity remains even after all diligent inquiries have been made, we are not justified in rejecting what is undoubtedly certain. It is a task of critical philosophy not to suppress mysteries, but to take note of them when and wherever they occur, and to throw light upon them by means of analogies with things that are more familiar to us.

The certitude and the ontological validity of primary ideas and first principles is naturally and logically prior to the theory by which the philosopher seeks to explain how this certitude is acquired, how our intellect comes into contact with being, and is determined and measured by it. The theory advanced in explanation of the exact manner by which something comes into existence, necessarily presupposes the existence of this same thing as an established fact. The obscurities accompanying any theory advanced in explanation of the way in which the actualization of the intelligible hidden in the sensible thing is effected, and how it is that the intellect gets to know by means of this actualized intelligible, must not cause us to deny, as the Subjectivists do, the fact that the intellect does know in this manner. In testing the power of our intellect, we must not strain it to the breaking point. We must proceed from the more certain to the less certain, and the obscurity of the latter must not cause us to reject the evidence of the former, no more than the difficulty of reconciling the immutability of God with divine freedom is a reason for doubting the existence of these two attributes, provided each has been logically deduced. If, in following strictly the rules of reasoning, we meet with certain obscurities, we must conclude that these veil a mystery, but not a contradiction. The classical theory of knowledge founded on the mutual relationship existing between being and intellect (considered in their vital aspects), and between intellect and being (objectively considered), in spite of its inevitable obscurities, nevertheless is in perfect conformity with the first principles of reason.

Concerning this theory, see Aristotle, De Anima, Bk. III, c. 5; St. Thomas, Summa Theol., Ia, q. 79, 84, 85, 86, 87, 88, and the Commentary of Cajetan; John of St. Thomas, Cursus Philosophicus, De Anima, q. 4 and q. 10; Sanseverino, Philosophia Christiana cum Antiqua et Nova Comparata, Vols. VI and VII; Liberatore, La Conoscenza intellettuale, 1857; Zigliara, De la Lumière Intellectuelle, Vol. II, pp. 18-135; Gonzalez, Philosophia Elementaria, pp. 500-542; Vacant, Etudes Comparfes sur Ia Philosophic de St. Thomas Cl sur celle de Scot, Vol. I, pp. 88-107; D. de Vorges, La Perception et la Psychologie Thomiste; Peillaube, Théorie des Concepts; P. Gardeil, "Ce qu'il y a de vrai dans le Néo-scotisme" (Rev. Thomiste, 1900 and 1901); Hugon, Cursus Philosophiae Thomisticae, Vol. IV, Metaphysica Psychologica, pp. 1-138; Sertillanges, St. Thomas d'Aquin; A. Farges, La Crise de la Certitude, 1907; H. Dehove, Essai Critique sur le Rfalisme Thomiste, romparf a lideelisme Kantien, Lille, 5907; P. Rousselot, L'Intellectualisme de St. Thomas, Paris, 1908.


Having defended the ontological validity of the idea of being, and of primary ideas in general, we must now take up the defence of the ontological validity of first principles and their absolute necessity, by showing what is their connection with being.


20) Intuition of first principles. They are perceived in the idea of being, which is the formal object of the intellect. The transcendent principle (principle of identity) is the ultimate basis of every proof for the existence of God. The affirmation of the objective validity of this transcendent principle tacitly implies the admission of the existence of the divine and transcendental being, who is absolutely identical with himself. In all forms of evolutionary Pantheism contradiction necessarily is the first principle.


By the process of analysis the philosophical reason refers these principles, which the intellect instinctively perceives in being, to being itself. We must give a detailed account of this connection, for it will furnish the answer to the objections of the Empiricists and of Kant against the necessity and the objective validity of the principles of sufficient reason and of causality. A critical survey of the principles of substance and finality will result in removing many of the difficulties which otherwise would greatly complicate the exposition of the proofs for the existence of God.

What the intellect first of all spontaneously perceives in being, is the truth of the principle of identity and of the principle of non-contradiction. For "that which before aught else falls under apprehension, is being, the notion of which is included in all things whatsoever a man apprehends. Therefore, the first undemonstrable principle is that the same thing cannot be affirmed and denied at the same time; this is based on the notion of being and not-being, and on this principle all others are based as is stated by the Philosopher in Met., IV, c. 6, n. 10." (St. Thomas, Ia IIae, q. 94, a. 2.)

In the IIa IIae, q. 1, a. 7, he writes: "The articles of faith serve the same purpose with regard to revealed truths, as self-evident principles do with regard to the truths acquired by natural reason. And in these principles there prevails a certain order, as some are positively included in others. Thus, all principles are finally reduced to this one, as to their first: 'It is impossible for the same thing to be affirmed and denied at the same time,' as is evident from what the Philosopher says in the Fourth Book of his Metaphysics."

A truth which has not been sufficiently emphasized is that, when we set down as an established fact the necessity and the objectivity of the principle of identity, it means that this principle is the ultimate basis of every proof for the existence of God, who is the self-subsisting Being, "ipsum esse subsistens." In explaining how the principle of identity is the fundamental law of thought and of reality, we are led to conclude that the fundamental reality, the Absolute, is in all things one and for all purposes identical with itself, Being itself, pure actuality, and, therefore, necessarily distinct from the world, which is composite and changing.

All the errors of the Empiricists and Subjectivists are refuted by means of this principle, which, therefore, must he fully discussed by us here.

St. Thomas, in his Commentary on the fourth book of Aristotle's Metaphysics (Lect. VI), proves that there must be a transcendent principle, by which simple apprehension and judgment, the first two operations of the mind, are compared. There can be no such thing as an indefinite series of concepts, for by the analysis of those which are more comprehensive than others we finally arrive at a first concept, the simplest and most universal of all, namely, the concept of being—that which exists or can exist. This idea of being, which is implied in all other ideas, must be absolutely the first for the intellect, which otherwise could form no concept of anything whatever. If, in the series of concepts, there is one that is first, then in the series of judgments also, there must be one that is first. And the first judgment, the simplest and most universal of all judgments, must depend upon the first idea, and being must be the subject of the proposition, and what first of all applies to being must constitute the predicate. By what formula can this truth be accurately expressed? Aristotle says that "it is impossible for anything to exist and not to exist at the same time and in the same sense." This axiom may be expressed in a simpler form by saying: "That which is, cannot be that which is not." It is important to note carefully the order of these primary notions.

Idealistic evolutionism, not distinguishing between being in general and divine being, starts out, as can be seen in the case of Hegel, by accepting the idea of being and its opposition to not-being, but denies that this opposition is absolute. Let us see how St. Thomas views this question, following, as usual, the teaching of Aristotle.

Our intellect perceives first of all the idea of being, and afterwards, by opposition, not-being; it then formulates three affirmative propositions, to which correspond three negative propositions.

See Javelli, O.P., in IV Metaphysicae Aristotelis, q. 6, fol. 739.


The first of these propositions is: "Being is being," and the negative proposition corresponding to it: "Being is not the same as not-being." The second is that: "Everything that is being, is being," from which it follows that "no being can be not-being." The third is: "Every being either is or is not," from which it follows that "Nothing can at the same time be and not be."

In the first of the negative propositions we have the principle of contradiction, or rather the principle of non-contradiction, in its simplest form. Its corresponding affirmative may seem to be tautological. In matter of fact, however, the accompanying predicate serves a real purpose, as clearly appears if both propositions are combined into one, after the manner of Parmenides, to wit: Being is being, not-being is not-being. Such expressions serve a useful purpose, for when we wish to emphasize the difference between things we often say, for instance, that "flesh is flesh," and "spirit is spirit." But these two affirmative propositions, which are in opposition to each other, can be reunited in one negative by saying: "Being is not not-being."

It is in this formula, which manifestly excludes tautology, that St. Thomas and his school, following Aristotle, recognize the supreme principle of thought, which they call the principle of contradiction.

As for the principle of identity, it may be formulated thus: "Being is being, or, every being is being." Expressed in this simple, though apparently tautological form, the principle of identity precedes that of contradiction, and this for the reason that every negation must be based on an affirmation. But if we wish to express explicitly the notion of identity contained in the formula which enunciates the principle of identity, it must assume the simplest form of the principle of contradiction. In matter of fact, identity is unity of substance, just as similarity is unity of quality, and equality is unity of quantity.

"When we say that things are the same, we mean that they are one in substance (which, interpreted in its fullest sense, means perfect unity); but the word like implies unity in quality, . . . and equal means unity in quantity." (St. Thomas, In X Metaph., Lect. 4).


The opposition between "the same," and "the other," and between "identical" and "different," presupposes that between "one" and "several." And the idea of unity or undivided being presupposes the ideas of "being," "not-being," and "division;"

"The first of all notions reached by the human mind is that of simple 'being,' and then 'not-being,' 'division; and 'oneness' follow in logical order; finally, the mind acquires the notion of 'multitude,' in which is implied that of division." (St. Thomas, In IV Met., Lect. 3).


and these ideas are all that we require to enable us to formulate the principle of contradiction.

If we wish to arrive at a clearer understanding of the explicit formulas of the principle of identity, we must note, as St. Thomas did, the order in which the notions of "being" (ens), "thing" (res), "unity" (unum), "something" (aliquid), "true" (verum), and "good" (bonum), follow one another. In De Veritate, q. 1, a. 1, St. Thomas explains this order as follows: "That which the intellect perceives first of all, and which is most evidently known by it, is being (ens), and it is into this concept that the intellect resolves all its other concepts. All the other concepts, therefore, denote something which is added to being. But ‘being' cannot receive any additions which are extrinsic to it, as is the case with additions accruing to a genus; for these differences, external to the idea of ‘being,' would mean nothing; and all nature, even in that which is specific to it, is still essentially ‘being.' Therefore, that which is added to ‘being' cannot be extrinsic to it, but simply expresses a mode of being not denoted by the term ‘being' itself. Amongst the modes of being we must distinguish (1) the particular modes which constitute the various genera or categories of the real, such as substance, quantity, quality, relation, action, passion, etc.; (2) the general modes which belong to every being, to every substantial or accidental reality, and which transcend the categories, and for this reason are called transcendentals. These general modes are in turn subdivided, according as they apply to every being, either as considered in itself, or relatively to something else.

"What applies to every being considered as such, may apply to it either affirmatively or negatively. Affirmative predication is concerned first of all with the essence, which is expressed by the word ‘thing' (res). This name, as Avicenna pointed out, differs from that of ‘being,' in that ‘being' denotes primarily the act of existing and through it that which exists; whereas the word ‘thing' (res) primarily denotes the essence or quiddity of that which is.

"Negatively, what is predicated of every being as such is ‘indivision,' which is expressed by the word ‘one.' To say of a being that it is one, is to say that it is undivided. If a being were actually divided, it would have no determinate essence. If it is simple, it is undivided and indivisible; if it is composite, it ceases to be when it is divided. (See Ia, q. 11, a. 1).

"Relatively to some other thing than itself the name ‘something' applies strictly to every being, precisely for the reason that it is distinct from any other thing (aliquid quasi aliud quid). Hence every being is one, in so far as it is undivided in itself, and it is something, in so far as it is divided or distinct from others.

"Finally, every being may be considered relatively as referring to that which by its nature comes in contact with all things, that is to say, the soul or the spiritual nature in general, in which we distinguish a cognitive faculty and a volitional or appetitive faculty. The relation of being to intellect is expressed by the word ‘true,' and its relation to appetite by the word good."


Copyright ©1999-2018 e-Catholic2000.com