Living Tradition
Editor: Msgr. John F. McCarthy, J.C.D., S.T.D.Distributed several times a year to interested members.
Associate Editor: Rev. Brian W. Harrison, O.S., M.A., S.T.D.  Not to be republished without permission.
Please address all correspondence    e-mail:
Living Tradition, Oblates of Wisdom, P.O. Box 13230, St. Louis, MO 63157, USA

No. 139 Roman Theological Forum | Article Index | Study Program January 2009



by John F. McCarthy


19. A subjectivist philosophy. Many historians have characterized the philosophy of Immanuel Kant (1724-1804) to be a forging of British empiricism and continental idealism into a higher synthesis which Frederick Copleston, in his History of Philosophy, calls “a triumph” over both.1 Kant began with a critique of the materialism of David Hume (1711-1776) and added to it another critique of the idealist tradition of René Descartes (1596-1650), Gottfried Wilhelm von Leibnitz (1646-1716), and Christian von Wolff (1679-1754). In this way Kant undertook to bring together, on the one hand, the mechanism and determinism of the empiricist approach, based on the model of Newtonian physics, and, on the other hand, the theories of freedom and deduced ideas, developed by Descartes, Leibnitz and other idealist philosophers, into one contrasting system of thought which Kant labeled “transcendental idealism.” Agreeing with Hume that whatever we know must be given in sensory experience, Kant reasoned that knowledge must also be somehow constructed by and within the mind of the knower, because strict universality cannot be derived from items of sense experience in themselves, so he postulated the function of a priori forms in human consciousness, the first of them being the forms of space and time.2 This idea allowed him to retain the empiricist practice of regarding the impressions of sensory data as the only objects of scientific knowledge, while seeming to open the way also in human consciousness for a rationally legitimate but scientifically indemonstrable belief in freedom, God, and the immortality of the soul (KC, p. 455). Kant did not deny the empiricist idea that true science deals only with observations of the material world, but he enclosed these observations of the material world within what to him are the merely subjective forms of space and time and then other a priori forms said to exist only within the consciousness of the individual thinker. This gave to Kant a subjectivist philosophy of the material world.

20. Kantian terminology. Hume had assumed that the real constituents of human experience are only discrete, atomic perceptions, and that the human self is just a bundle of these perceptions having no essential unity (CHP, p. 199). Kant added to this outlook the transcendental unity of human apperception (consciousness) as a basic condition of human experience (KC, pp. 94-95), noting that Hume had granted it to be necessary that sensory conceptions have an a priori, but it had never occurred to him that the understanding itself might be the author of the experience in which these objects were presented to it (KC, p. 92). Kant agrees that empirical cognitions alone are items of real knowledge (KC, p. 102), but human knowledge springs also from two main sources entirely within the mind: the power to receive sensory impressions, which he calls intuition, and the power to produce mental conceptions from these impressions, which he terms understanding, and, he adds, no knowl­­edge is possible without the simultaneous action of the two (KC, p. 62).3 In Kantian theory, the undetermined object of an empirical intuition is called a phenomenon, while the form, or deter­mination, of the phenomenon lies ready, a priori, in the mind and is distinct from all sensation. Thus, extension and shape are not objects of sensation but are merely internal powers that form the objects of sensation (KC, pp. 41-42). Reason, on the other hand, never applies directly to experience or to any sensory object; it applies to the understanding of the manifold of cognition (KC, p. 213). The particular function of reason is to arrange transcendental ideas into a system, that is, to give them connection according to a principle (KC, p. 374). Kant applies the term transcendental to all knowl­edge which is occupied with the mode of our knowledge of objects, rather than with objects themselves (KC, p. 38). Reasoning about objects or ideas not directly derived from sensory experience is always fictitious (KC, p. 373).

21. Transcendental idealism. Kant advocates what he calls transcendental idealism, according to which it is assumed that all things intuited in space and time and presented to us as extended bodies or series of changes have no self-subsistent existence apart from human thought. In other words, transcendental idealism holds that mental phenomena are not things in themselves; they are mere representations which, apart from their being perceived, are non-existent (KC, pp. 296-297). And even the whole world is not a whole existing in itself (KC, p. 304). In Kant’s view, the only a priori intuition is that of the pure forms of phenomena, which are space and time ((KC, p. 413). What we see as the extension and shape of bodies does not actually belong to external things themselves, because what seems to be external space is just the result of our own subjective disposition that enables us to have intuitions of these objects. Space does not exist, because, if the objects in space are subtracted, all that remains is a pure internal intuition, and this is the “empirical reality” of space (KC, p. 46). Time is simply “the form of the internal sense,” that is, “the form of the intuitions of self and of our internal state.” While space is the pure form of the intuition of external phenomena, time is the formal condition a priori of all phenomena, because all phenomena are in time, and this is the “empirical reality” of time (KC, p. 50).4 “The schema of substance is the permanence of the real in time” (KC, p.120). This idea of permanence does not come from any external experience; it is rather “an a priori necessary condition of all determination of time,” including also of the internal sense with reference to our own existence, and thence to the existence of external things (KC, p. 172).

22. Only phenomena are real. Kant avers that everything real is presented to us as a phenomenon, never as a noumenon, or thing in itself (KC, p. 199). The conception of a physical noumenon is not an arbitrary or fictitious notion, but it is incapable of presenting us with any positive data from beyond the field of conscious phenomena. A physical noumenon is, at best, a not-to-be-excluded notion of an unknown something (KC, pp. 188-189). In the epistemology of Immanuel Kant, “reality, in the pure conception of the understanding, is that which corresponds to a sensation in general; [it is] that, consequently, the conception of which indicates a being (in time)” (KC, p.120), or, in other words, “that which coheres with the material conditions of experience (sensation) is real” (KC, p. 166; cf. p. 410). “Reality is concerned only with sensation, as the matter of experience, and not with the form of thought, with which we can no doubt indulge in shaping fancies. ... It is perception which presents matter to the conception that is the sole criterion of reality” (KC, pp. 168-169). “The conceptions of reality, substance, causality, nay, even of the necessity of existence, have no significance out of the sphere of empirical cognition, and cannot, beyond that sphere, determine any object” (KC, p. 391). The intelligible object of transcendent ideas may be called a “transcendental object,” but, since such an object has no connection with empirical conceptions, we may not affirm its existence (KC, p. 333). “Transcendental ideas . . . cannot be conceptions of objects, and, when thus considered, they assume a fallacious and dialectical character” (KC, p. 374).

23. Transcendental ideas. For Kant the critique of reason “forms part of the native rights of human reason, which recognizes no other judge than the universal reason of humanity; and as this reason is the source of all progress and improvement, such a privilege is to be held sacred and inviolable” (KC, p. 430). And so, in metaphysics mistakes can be avoided “if we are sufficiently cautious in the construction of our fictions, which are not the less fictions on that account” (KC, p. 29). The pure conceptions of reason are transcendental ideas. From the cognition of self to the cognition of the world, and through these to the supreme being, the progression is so natural that it seems to resemble the logical march of reason from the premisses to the conclusion (KC, p. 231). The first trans­cen­dental idea of pure reason is the ego, considered merely as a thinking nature or soul. The second transcendental idea is the conception of the universe. The third trans­cendental idea, containing the hypothesis of a being which is valid merely as a relative hypothesis, is that of the one and all-sufficient cause of all cosmological series, in other words, the idea of God (KC, pp. 395-396). Of these three, only the transcendental unity of apperception is objectively valid (KC, p. 98). But to show reasons why, for instance, we are endowed with precisely so many functions of judgment and no more, or why time and space are the only forms of our intuition, is impossible to explain (KC, p. 101), and the intuition of self does lie in the original constitution of the mind (KC , p. 59). But our awareness of ourselves as knowing subjects is only as a phenom­enon, and not as we actually are in ourselves (KC, p. 107).

24. The transcendental speculation of reason. Kant goes on to say that we are inclined to assume the existence of “a wise and omnipotent author of the world,” not as having absolute and objective reality, but merely as an ideal being that we think about (KC, p. 402). Kant’s “transcendental speculation of reason” relates to three things: the freedom of the will, the immortality of the soul, and the existence of God (KC, p. 453). Kant is certain that we shall never see sufficient demonstrations of the two cardinal propositions of pure reason, namely, the existence of a Supreme Being and the immortality of the soul. We need not, then, he says have recourse to invalid scholastic arguments, because we have on our side the support of the subjective maxim of reason, and we can, therefore, look upon all the existing sophistical “proofs” with calm indifference (KC, pp. 423-425). Reason does not assure us of the objective validity of the conception of God; it merely gives us the idea of something on which the supreme and necessary unity of all experience is based (KC, p. 390). This world is, it is true, an intelligible world; for of such a systematic unity of ends as it requires, the world of sense gives us no hint. But the reality of this world can be based on nothing else than the hypothesis of a supreme original good (KC, p. 462). In Kant’s “transcen­dental metaphysics,” the ideas of the soul, of freedom, and of the existence of God become objects of faith rather than of knowledge (CHP, pp. 27-28). In the Idea of God we think the totality of supersensible or noumenal reality, and in the idea of the world we think the totality of sensible reality (CHP, p. 174). God and the world are not “substances outside my ideas but the thinking whereby we make for ourselves objects through synthetic a priori cognitions and are, subjectively, self-creators of the objects we think” (CHP, pp. 174-175).

25. Practical knowledge. In Kant’s terminology, theoretical knowledge is knowledge of what is, and practical knowledge is knowledge of what ought to be (KC, p. 368). Theoretical knowledge is speculative when it relates to an object which is not given in and cannot be discovered by means of experience (KC, p. 369). Kant maintains that no speculative “metaphysics” that tries to use pure concepts of the mind (soul, substance, etc.) in order to transcend sense experience and envision so-called realities going beyond the senses can legitimately be called a science or is even anything more than fiction (KC, p. 29). To Kant it is evident that the ultimate intention of nature, in the constitution of our reason, has been directed to the moral alone (KC, p. 455). The faculty of reason, accordingly, enunciates laws which are imperative, or objective, laws of freedom, and which tell us what ought to take place, thus distinguishing themselves from the laws of nature, which relate to that which does take place. The laws of freedom, or of free will, are hence termed practical laws (KC, p. 456). Kant says that he is “morally certain” that there is a God and another world, but only because these beliefs are interwoven with his moral nature (KC, p. 469). To view ourselves called, as Leibnitz does, to a kingdom of grace, in which all happiness awaits us, is a practically necessary idea of reason (KC, p. 461), The moral law in us, “this mighty, irresistible proof,” accompanied by an ever-increasing knowledge of the purposive finality in everything we see around us, does still remain to humanity (KC, p. 246).

26. Freedom of the will. Kant assumes that there are pure moral laws which prescribe the use that the rational being should make of his freedom, and it is, then, in their moral use that the principles of pure reason possess objective reality (KC, p. 458). Copleston sees this as meaning that practical reason produces its objects and makes them real (CHP, p. 103). The whole interest of reason, speculative as well as practical, is centered on the three following questions: 1) What can I know? 2) What ought I to do? 3) What may I hope (KC, p. 457)? The human will is a faculty of self-determin­ation existing in man independently of all sensuous coercion (KC, p. 317). The idea of a moral world has, therefore, objective reality, conceived, however, only as an object of pure reason in its practical use (KC, p, 459). So far as relates to the empirical character of the world there can be no freedom (KC, p. 325), since the principle of an unbroken connection between all events in the phenomenal world, in accordance with the unchangeable laws of nature, is “a well-established principle which admits of no exception,” so that, if phenomena were absolutely real things in themselves, freedom would be impossible. Certain effects may, therefore, be considered to be free in relation to their intelligible cause and necessary in relation to the phenomena of which they are a necessary consequence (KC, pp. 318-319)

27. The “categorical imperative. ”Regarding Kant’s teaching on free will and religion, Copleston makes some further observations along the following lines. Kant postulates that man is an end in himself, and that the will of man, taken as a rational being, must be regarded as the source of the moral law which he recognizes as universally binding. This is the principle of the autonomy of the human will. And to say that the moral will is autonomous is to say that it gives itself the law which it obeys (CHP, pp.120-121). As belonging to an intelligible world, man finds himself under moral laws which have their foundation in reason alone. The idea of freedom makes each human thinker a member of an intelligible world to which his actions should conform, and this is the categorical imperative. No human reason can ever discern how this imperative is possible, but it is a necessary consequence of the presupposition that the will of an intelligence is free, and, in Kant’s view, the practical necessity of this moral agency is sufficient for the laws of morality (CHP, p. 125). The categorical imperative implies a call to a moral perfection that cannot actually be attained in the time allotted, and thus emerges the idea of the immortality of the human soul, which, again, is not demonstrable by reason in its theoretical use (CHP, p. 130). The same moral law leads us, on a practical level, to postulate the existence of God, and theoretical reason should try to conform to this belief (CHP, p. 134) Thus, “morality leads inevitably to religion” (quoting Kant), but Kant rejects any idea of unique divine revelation or the legitimacy of an authoritarian Church (CHP, p. 136). He claims that natural scientists should see a purposive unity in physical nature that could imply the work of a divine hand, but as a conclusion having only subjective validity (CHP, p. 144).


28. The reductive approach. The empiricism of Immanuel Kant, like all empiricism, has a reductive approach to reality. This reductive approach can be illustrated by the following hypothetical example. Michelangelo’s painting of the Last Judgment on the front wall of the Sistine Chapel has been viewed by millions and often photographically reproduced. But suppose that a scientific study of this wall were undertaken by scientists always holding their eyes close to the wall and using magnifying glasses and microscopes as technical instruments. And let us suppose that every square centimeter of the wall was precisely measured and chemically analyzed so that what seemed to be, for instance, smooth and even lines turned out under scientific examination to be jagged and uneven, with the colors overlapping, and other results of this kind. It could happen that those responsible for this scientific study might begin to declare that there is no picture at all on the wall and to affirm that those who claim to see a picture there are obstructing the progress of science. This reductive view of the wall might be called “scientific” by a certain class of thinkers, especially if they disagreed with the message of the painting, but it would actually be a violation both of reason and of common sense.

29. Kant’s reductive approach. Now, Kant’s assumption that we cannot know what exists outside of our mind, because all that our senses receive are “atomic impressions” coming from sources to which we have no immediate access (no. 20 above), is a violation both of reason and of common sense. It is a violation of reason, because it can easily be shown that mirrors, even though they receive only “atomic impressions” of external things, nevertheless reproduce those things as they are, and so also with our human sensory perception. And it is a violation of common sense, because everyone knows that we are immersed in an external world of material things that are spatially spread out in a sequence of time. In a football game, for instance, each of the players knows that the bodies of twenty-two players are spread out there, that there is a real football, a real line of scrimmage, two goal-lines a hundred yards apart, and a definite length of time until the end of the game. This whole scenario could not really be situated only within the minds of the players, and it is difficult to believe that Kant, as he took his daily afternoon walk, did not realize that he was passing through real and extramental space and time. In fact, he admitted that no one can really help thinking that these objects are extramental, and he had to constantly force his mind into conformity with his theory. And this gave rise for Kant and for many of his followers to a confused understanding of the function of common sense.5

30. Common sense. Thus, Kant attacks the “naturalists of pure reason” who claim that common sense without the aid of science or of metaphysical speculation can provide better answers to the great questions of life, and who maintain that the neglect of all scientific means is the right way to advance our knowledge. And he notes the absurdity of such a stand (KC, p. 483), but this depiction is largely a caricature of the question at hand. Of course, opposition to all technical science and metaphysical speculation is absurd. And there was, indeed, in Kant’s time a “school of common sense” that arose in Scotland and did excessively oppose metaphysical speculation, basing its approach upon the conviction that “philosophy has no other root but the principles of common sense; it grows out of them and draws its nourishment from them.”6 It carried its opposition to metaphysical speculation too far, but it was mainly opposed to the empiricism of David Hume and the subjectivist speculation of the continental idealists7, and its stand was basically correct in the sense that both natural science and sound metaphysics do grow out of common sense, which is just another name for common science, and which arises from a number of self-evident principles “which are the foundation of all reasoning and which neither admit of direct proof nor need it.”8 Actually, all sound physical science and philosophy, so it seems, are based upon that realism of common sense that is characteristic of adults of balanced mind. It is, indeed, a function of technical science to correct the illusions to which common sense is sometimes subject, but most of what common sense sees is not illusionary, and, to the extent that technical science does not convincingly correct occasional misreadings of reality performed by common sense, it is logically bound to adhere to what common sense presents. Even natural scientists working in a laboratory have to use common sense in carrying out their experiments.

31. Moderate realism. In the present reflection, Thomist philosophy and theology, vis-à vis empirical science, are approaches plainly based upon a technical development of common sense. It is a pity that Kant limited his critical philos­ophy to the parameters of British empiricism and continental subjectivism, while he ignored the wide expanses of Thomist reasoning. In the moderate realism of Thomas Aquinas, as a technical development of common sense, the reality of things outside of the mind constitutes the remote object of human knowledge, while the conscious perception of these things constitutes the proximate object of human knowledge. Kant’s error here lies in making the proximate object of human knowledge (the mirror-like image) into the remote object and thence in denying the very existence of the remote object of human knowl­edge. For Kant, space and time belong only to human consciousness and have no reality apart from it (KC, p.102); they are for him the necessary internal forms for the assembly of all sense perceptions into phenomena of the imag­ination. On the contrary, in Thomist philosophy, space and time are beings of the mind with a foundation in external reality. This means that space as a relation of distance and time as a measurement of motion exist only in the mind, but they are based upon real external extension and real external motion or change.9

32. The common-sense concept of reality. But what is reality? For Kantian subjectivism, reality is constituted by and limited to the conscious objects of sensory perception, and not by anything outside of the mind. Kant maintains this position in sheer opposition to common sense and common experience, even though the very idea of reality is rooted in common sense, and it consists in the distinction that is made early in life between truth and falsehood, between truth and error, and between what is real and what is non-real inasmuch as it is either a deception, an illusion, a lie, or a fantasy. Hence, the correction of illusions is also a function of common sense, and here technical science comes to its aid by the use of precise instruments and methods, but never by ignoring observations of common sense and simply saying “yes, this looks obvious, but here you must ignore the obvious,” as many empiricists and all subjectivists do.

33. Intellectual consciousness. The Aristotelian/Thomist theory of proximate versus remote objects of knowl­edge opens the way to a better understanding of the human mind. Within human consciousness lies human intelligence, the proper function of the rational intellect with which man is endowed, essentially divided in its function between a knowing subject and the object of his knowledge. Whenever a human being is conscious and thinking, he is a knowing subject viewing objects. Thus, the unity of the perception of one’s own existence is given in consciousness and is a spontaneous awareness, contrary to the claims of empiricists, mechanists, and all other materialists. Kant agrees basically with this, but only reductively, because for him there is no independent intuition of the knowing subject apart from its connection to the act of sense perception. Now, awareness of self as a knowing subject is a characteristic of all higher animals, because the act of all finite knowing is made up of an object of knowledge and of a knowing subject of that knowledge. But, while animal knowing contains a merely spontaneous knowing subject, intelligent human knowing contains the power of reflective awareness within the unity of apperception. It is true that the unity of this intelligent apperception has no content of its own, since it is an empty factor of finite intelligence as such, but it has the ability to discover constituents lying behind this awareness by seeing them as objects.10 As far as mental objects go that are not perceptions of the senses, he accords a kind of validity, that is, a kind of reality, also to the mental objects of time, space, and “the transcendental unity of apper­ception,” but why these mental objects alone, in addition to phenomena of the sensory imagination, are real he cannot explain; nor can he produce any proof from his power of reason to show why the mind is constructed as it is - as far as logical categories and functions of judgment go (cf. no. 23 above). Hence, much of Kant’s critical epistemology is based on what he simply assumes and takes for granted.

34. The “Kantian split.” In Kant’s terminology, transcendental philosophy is the idea of a science which is the system of all the principles of pure reason (KC, p. 39). He says that the critique of reason leads to science, while the “dogmatic” use of reason without this criticism leads to gratuitous assertions and equally gratuitous counter-assertions (KC, p. 422). As Copleston puts it, Kant “affirms the value of metaphysics considered as a natural disposition but denies its claim to constitute a true science which gives us theoretical knowledge of purely intelligible reality” (CHP, p. 27). Kant cautiously affirms the three “transcendental ideas” mentioned above (no. 23), while sweepingly excluding as confusion in which “all insight and knowledge cease to exist” (KC, p. 285), most of the ideas presented hitherto by other philosophers, not only by the continental idealists, but also (without a fair hearing) by the philosophy and theology of Thomas Aquinas and his peers. But even the few transcendental ideas that Kant retains are to him “fictions” that are always to be recognized as such (no. 23 above). And here appears the “Kantian split” mentioned by Cardinal Ratzinger as a defect of modern thought that needs to be remedied (no. 3 above). For Kant, only the intra-mental objects of sensory perception and things closely tied to it, such as time and space, are “real,” while all other objects are lacking in reality, and all of the transcendental ideas of conventional metaphysics are thus to be recognized as fictitious (no. 22 above). Now, if we define “science” as “certified knowledge of the real as such,” in Kant’s “critical” view, all of the objects of conventional philosophy and theology are unscientific. Kant avers that intellectual hypotheses and faith should not be called into the service of our practical interests; nor should we present them under “the pompous titles of science and insight,” for speculative knowledge cannot find any other objective basis than sensory experience (KC, p. 286). Now, sensory experience does have general rules of unity in the synthesis of phenomena, but, he adds, the objective reality of these rules can always be shown from sense experience itself (KC, p. 127).

35. Kant’s critical philosophy as “permissible fiction.” Kant tells us that there is a natural tendency to philosophize, but for him this tendency, apart from his own reductive permissions, has no basis in or logical connection with science and objective reality; it is a universe of discourse unto itself. Kant allows himself to venture a little into “critical philosophy,” but with the proviso that such thinking is only permissible fiction at best (no. 23 above). He claims that science and reality pertain only to thoughts directly connected with sense experience, but he offers no convincing arguments for this opinion. The fact is that most of the things that people really know are learned from others. Not even most of the specialized knowledge of empirical scientists is known from their own personal sense experience. Knowledge of history and the majority of what people know about real things depend on the testimony of others, and there are common-sense rules, as well as further technical rules, for judging whether such testimony is reliable. But Kant rules out a priori all such testimony on the ground that “the only true teacher” is sensory experience (KC, p. 285). Kant’s limited notion of “the only true teacher,” sets up an inadequate idea of historical fact and historical knowledge. Applying his notion that all phenomena “are not given as things in themselves, but in experience alone, he says that “things that really existed in past time” are to him “real objects only in so far as I can represent to my own mind that a regressive series of possible perceptions . . . conducts us to an elapsed series of time as the condition of the present time.” When Kant says that objects existed prior to his experience: “this means only that I must begin with the perception present to me, and follow the track indicated, until I discover them in some part or region of experience” (KC, p. 298). Here, as elsewhere, Kant is in violation of that common experience which recognizes the external reality of historical events and the value of testimony in the acquisition of knowl­edge of the past. Certainly past events do not have present existence, but Kant’s approach takes the documented facts of history entirely out of the realm of external reality and reduces them to some kind of fiction.

36. Kant’s “universal reason” as the supreme judge. Kant holds as a fundamental principle that the “critique of reason” is a native right of man that is subject to no other judge but itself (no. 23 above). Unfortunately, this is the basic presupposition of all rationalism. He considers “universal reason” to have a “sacred and inviolable” right to judgment that is not subject to any external authority, (not even to the authority of God), and on this “sacred” ground, he sweeps away all appeals to divine revelation and all claims of a divinely established Church (no. 27 above). Moral conscience he acknowledges, but he makes it totally subject to a use of reason that is not grounded in objective truth. This is an egoist worldview that Kant has constructed around his own unaided reason. Yes, man has a tendency to think, whether wholesomely or perversely, but man also has an obligation to conform his reason to objective truth, and this includes conformity to historical reality and to common sense, while Kant’s unrealistic and arbitrary definition of reality puts out of focus, not only the validity of historical testimony, but even the very basis in common experience of the concept itself of reality. Kant views the physical world as a totally closed system of causality with which free human acts cannot in any way interfere (no. 26 above). With this doctrine the effects of Kant’s “free acts” are presented as a purely aesthetic illusion, and this stand is counter to common sense, for it is easy to demonstrate at any time that free human acts really can have an intervening effect upon the physical operation of Nature. Hence, Kant’s appeal to “universal reason” is actually only an appeal to his own fallible reason.

37. Kant’s idea of subjective reason. Kant characterizes all speculation about supersensible things in themselves as mere objects of faith that do not exist outside of ourselves but are self-created by us (no. 24 above) except as limited to what ought to be in the view of moral reasoning (no. 25 above). Thus, he sets up a real world of empirical science and a totally separate and non-real world of moral tendency and obligation. While he says that he is “morally certain” that there is a God, and that it is perfectly permissible to use faith-based language, he requires a prior recognition that these objects of practical reason and of faith do not in any way constitute real knowledge (KC, p. 426). So, by “morally certain” he means acceptable to a tendency of my critically disciplined mind to entertain the unreal idea of God, but with the proviso that such reasonings are fictitious at best. For the existence of God and the immortality of the human soul, Kant favors pure subjective reason over objective proof (no. 24 above). Obviously, of course, to favor subjective reason over objective proof is the flimsiest of arguments, and the mere inclination of people to assume the existence of a wise and omnipotent Author of the world is not a sufficient argument in itself. Skeptics and free-thinkers have often said things like this: “Some people like music, some like sports, some like narcotics, some like drama, and some like religion.” In other words, Kant reduces religion to an aesthetic preference whose conclusions have for him no certitude in objective reality.

38. A Thomist approach to reason and understanding. Kant bases his stand on wrong definitions of knowledge, reason, understanding, and reality itself. The way to liberation from these epistemological errors is open through an application of the principles and teaching of Thomas Aquinas. The word Science is commonly understood to mean “certified knowledge.” Kant holds that only knowledge certified by sensory experience is scientific, while all other claims to knowledge are at best just faith or opinion (KC, p. 466). This brings up the question of how knowledge, and understanding arise. Knowledge of concrete, individual, material things arises from sense perception, while what these things mean pertains to understanding. Simply put, understanding is the knowledge of one thing, or truth, in relation to a previously known thing, or truth. This relation, or inference, can be immediate or mediate. In the first case, there is a mere juxtaposition of the new thing, the remote object, to the previously known thing, the proximate object in the comparison. In the second case, a logical process is involved. Aristotelian/Thomist theory postulates that there are innate principles in human intelligence. From these beginning principles the rest of logic can be deduced. All people of sound mind think according to these principles, and thus science arises. There first arises common science, otherwise known as common sense. This has been developed into technical science, which uses precise methods and technical terms. In the Thomist synthesis, the word scientia means both “knowledge” and “science,” and this is reasonable, because science is certified knowledge, and knowledge that is not certified is not really knowledge; rather it is error or mere opinion. But scientific knowledge, that is, real knowledge, is not limited to one’s own sensory experience; it includes the certified testimony of others and validly reasoned conclusions regarding these objects. Kant unreasonably makes a nonfunctional separation of reason and understanding in the sense that he calls the perception of material objects understanding and logical reflection about non-material mental objects reason. This division is false, because even empirical scientists reason about material objects in order to obtain an understanding of them, and there is a treasury of understanding in logical reflection about non-material objects, as Thomism bring out so effectively. Kant writes off this treasury of understanding, but only on the basis of false definitions of knowledge, reason and understanding.

39. The name of science. From the Thomist point of view, not only documented history, but also sound philosophy and sound theology deserve the name of science, because they produce knowledge and understanding of reality. We may define history as “the knowledge of past reality as such,” including in its content all verified events of the past. Philosophy is “the science in which natural reason, apart from divine revelation, seeks to understand all things by a knowledge of their first causes.”11 Finally, sacred theology is the science of revealed reality as such, and it applies to “the whole study of revealed truth”12 Each of these three sciences is a technical development of common science, as also is natural science. And each of these sciences has its own mental frame of reference. The science of history is organized around the concept of “the past as such,” and it reaches back from known developments to the origins of these developments. It is essentially a backward view. The science of philosophy deals on the level of natural reason with knowledge that extends beyond the purview of the natural sciences. And the science of sacred theology develops from a knowledge of revealed truth through the use of logic and natural reason.

40. Conclusion. The philosophy of Immanuel Kant has been too influential to be summarily dismissed, but the thought of the Fathers of the Church and of Catholic philosophers and theologians over the centuries has been even more influential, and so neither should their thought be summarily dismissed, as Kant clearly does. For instance, it is a pity that Kant chose a sweeping rejection of Thomist epistemology rather than a serious study of it. Contrary to the valid insight of common sense, Kant based his philosophy upon the reductionist approaches of British empiricism and European continental idealism, out of which he constructed a dualism that denies the reality of philosophical and theological truth. This dualism enabled Kant to provide some standing for the ideas of human freedom, God, and the immortality of the human soul, but only as permissible aesthetic pursuits. There is no reason why scientific thinking has to be limited to methodical conclusions from sensory observations. In fact, logical thinking and verified testimony can be the basis of true sciences. Nor is there any reason why scientific knowledge cannot arise from supersensible realities revealed by God. Faith begins from hearing, and most of what we know about natural things we have learned from others. Sense knowledge is not the only certified knowledge. The objects of Christian faith are also sources of valid knowledge. But philosophical conclusions that are based on a denial of common sense have no claim to validity. The aim of philosophy is the understanding of truth, but Kant’s limitation of understanding to the perception of sensory images is off the track. So also is his definition of reason, and the making of his approach to reason the supreme judge of all values. Actually, the Aristotelian/Thomist use of criticism is more refined and more serviceable for correct thinking than is Kant’s critique of reason. The philosophy of Immanuel Kant is a frontal attack against Christian faith that needs to be refuted point by point, as has, unfortunately, not been adequately done over the years even by Catholic philosophers and theologians, although summary replies, such as that of Frederick Copleston frequently referred to in this discussion, have not been lacking. Much work remains to be done, and, in the next part of this presentation, I hope to bring out in particular how the influence of Kantian thinking has influenced and continues to influence the exegetical thinking of Catholic Scripture scholars and theologians.


1 Frederick Copleston, History of Philosophy, vol. 6, Modern Philosophy, Part II, Kant (Image Books: Garden City, NY, 1964) [hereinafter referred to as CHP], p. 218.

2 Cf. Immanuel Kant, Critique of Pure Reason (English translation of the second edition, 1787: New York: Dutton and Co., 1934 [hereinafter referred to as KC]) pp. 102 and 413.

3 In Kant’s terminology, an intuition clings singularly to the sensory perception, while a conception has a mediate relation to the sensory perception and may be common to several things. A pure conception, having its origin in the understanding alone, and, therefore, not in a sensory perception, he calls a notion. A representation formed from notions, and, therefore, transcending the possibility of sensory experience, he calls an idea, or a conception of reason (KC , p. 222).

4 Problematical idealism. In refutation of Descartes’ “problematical idealism,” Kant defends the following theorem: “The simple but empirically determined consciousness of my own existence proves the existence of external objects in space.” His proof goes like this. I am conscious of my own existence as determined in time. The consciousness of my own existence is at the same time an immediate consciousness of the existence of other things without me. Our proof shows that external experience is properly immediate, that only by virtue of it – not, indeed, the consciousness of our own existence, but certainly the determination of our existence in time – is possible. In (the representation I am) we cannot find any knowledge of the subject, and therefore, also no empirical knowledge, that is, experience. For experience contains, in addition to the thought of something existing, intuition, and in this case it must be internal intuition, that is, time in relation to which the subject must be determined. But the existence of external things is absolutely requisite for this purpose, so that it follows that internal experience is itself possible only mediately and through external experience (KC, pp. 170-172). And we are obliged to employ external intuition to be able to represent the successive existence of ourselves in different states (KC, p. 179). Probably not a contradiction. Some writers, including Frederick Copleston, have seen the above-quoted theorem as being in contra­diction to Kant’s basic principle that the external world and the things in it do not really exist. But I think that a closer look reveals some consistency in Kant’s reasoning. Descartes’ opening statement was Cogito, ergo sum (“I am thinking, there­fore, I am”). Kant counters that the fact that I am thinking does not prove that I am, if, by “I am” is intended anything about me except the mere existence of a knowing subject as such, because this factor of consciousness is absolutely empty and has no content. And this seems to be true. But the consciousness that I am thinking can exist only in coincidence with an object that I am observing, and so the reasoning of Descartes, inasmuch as he holds rational substances to be conscious indepen­dently of external things (KC, p. 242) and tries to derive all philosophy subjectively from his Cogito, ergo sum, does not stand up. There seems to be no contradiction in this point of Kant’s reasoning, if we consider that he is here using the word “external,” not as meaning external to human consciousness, but rather as external only to what Kant calls the “internal sense “ and the sub­jec­tivity of Descartes’ cogito. It remains that for Kant the object being sensorially observed is always within the mind and never outside of the mind. Thus, he does not seem here to contradict his total subjectivism, although his claim that the thinking self can never establish himself reflexively as an object appears to me to be gratuitous and without foundation.

5 “(Kant) maintained that we must refrain from asserting dogmatically the existence of the thing-in-itself, though we cannot help thinking it. It is clear that Kant thought it absurd to reduce reality to a mere construction of the subject, and that he therefore looked on the retention of the concept of the thing-in-itself as a matter of common sense. . . . In (Fichte’s) opinion, Kant was a man who tried to have things both ways at once, and who therefore involved himself in hopeless inconsistencies” (CHP, p. 221).

6 Thomas Reid (1710-1796), Works (1863 edition), p. 101 (quoted in William Turner, History of Philosophy [Boston: Ginn and Co., 1929), p. 593).

7 Cf. F. Copleston, History of Philosophy (Garden City, NY: Image Books, 1963), vol. 4, p. 49.

8 Copleston, ibid., p. 49.

9 Cf. R.P. Phillips, Modern Thomistic Philosophy (Westminster, Maryland: Newman Press, 1950), vol. I, pp. 96 and 123.

10 Cf. my treatment of “Intellectual Consciousness” and “The Discovery of Truth” in The Science of Historical Theology (2nd printing, Rockford: TAN, 1991), pp. 15-25.

11 John A. Hardon, “Philosophy,” in his Modern Catholic Dictionary (second printing, Bardstown, KY: Eternal Life, 2001).

12 Hardon, “Theology,” op. cit.

Go to: Roman Theological Forum | Living Tradition Index | Previous Issue | Next Issue