A Critical Review of Kant’s First Critique

by E. M. Milco

Introduction

In a letter to St. Gregory Thaumaturgus, Origen of Alexandria famously writes of God’s injunction for the Israelites to take the spoils of the Egyptians with them into the desert and use them as materials for the construction of the tabernacle. He compares this repurposing to the use of pagan ideas for the advancement of Christian thought, and remarks that there is danger in the process, lest, just as some of the Israelites took these spoils and used them to make the golden calf, Christians bring forth heresies from their engagement with Greek philosophy. Here at The Josias, we would like to examine some important thinkers of recent centuries, to deconstruct their major works and ideas, and to pick out whatever in them is useful for the upbuilding of sound philosophy. The following post is the first in what we hope will be a series on the Spoils of Egypt, aiming to rob the better fruits of modern thought and, after melting them down and purifying them, find use for what remains in rebuilding the philosophical tabernacle which the great Scholastics once raised to house the riches of Divine Truth.

The Prefaces and Introduction

1. For my 17th birthday I received from my parents a copy of Werner Pluhar’s translation of Immanuel Kant’s Critique of Pure Reason, along with Descartes’s Discourse on Method and Meditations on First Philosophy. I had started reading philosophy the previous year with Plato, and, after devouring Mortimer Adler’s How to Read a Book, I was committed to educating myself philosophically through the “great books”, which Adler had conveniently enumerated in an appendix. I remember opening up Kant that day and treating the Critique with a great deal of reverence. It promised to be difficult and great and to give me answers about the foundations of knowledge, which I could use to frame a worldview. I took the day off of school and went to the local Starbucks to spend the day with Kant.

2. Over the past decade Kant has been a regular companion in my own philosophical journey, for better or worse. In what follows I would like to work through some points of enduring interest to me in his work: the beauty, the defects, some of the implications. I would offer a defense of the usefulness of such an exercise, but its merits will be evident to those who read it. Read, and judge for yourself.

3. Kant has a self-conscious style typical of modern German philosophers. He believes his project to be of world-historical significance, and believes that he is writing the last book on his subject that will ever need to be written. In the context of the past four centuries, this self-confidence seems a little silly, but it has its advantages. Our grave German thinker takes his work very seriously and wants to complete the task thoroughly. This makes it much easier for us to take him seriously, and gives one a degree of certainty that what he produces will represent the best of him.

4. In the original preface, Kant tells an allegorical story about Queen Metaphysics and her struggles with regard to her own legitimacy. The story he tells remains (to a degree) true to the present day, though his work to restore her rightful title has, alas, led to her dethronement, and her loyal defenders nowadays are usually found only among religious thinkers on the fringes. The stated goal of the book, to put Metaphysics on her feet as a legitimate science, has not only destroyed Metaphysics, but even helped to destroy science (in the classical sense of that word).

5. In various ways in the two Prefaces and Introduction to his work, Kant suggests that one of the core problems of metaphysics is that its practitioners rise so high in pursuit of reason that, transcending the limits of experience, they begin to make claims and apply principles in ways that are subtly illegitimate. The complaint is, in a way, a restatement of Aristotle’s classic adage from the De Caelo: “Parvus error in principio, magnus est in fine.” If one abstracts it from Kant’s project, according to which the metaphysicians’ fault is trying to use reason to make extra-empirical claims, he is right. One of the common errors of metaphysicians, and of philosophers generally, is that they tend to grab hold of a few principles of thought at the beginning, and, failing to adequately hone them, they apply them so giddily to every possible question that they end up erecting a logical edifice reflective more of their own imperfect ideas than of the reality they are trying to understand. Ironically, this problem applies to Kant as well, despite his earnest efforts to the contrary.

6. The way to avoid this error is to not only to re-examine one’s principles perpetually in their implications and in experience, but to treat the principles as, in a way, the endpoint of philosophical investigation, as well as the beginning. Without any doubt, all knowledge begins with experience, as Kant famously says in the first line of his Introduction, but he is wrong to claim (as he does repeatedly) that cognition terminates in experience. It terminates in an understanding of the principles of being and nature which are the basis of what is discovered in experience. The goal of the philosopher isn’t only to discover the rules of thought which make knowledge of the outer world possible, but to employ the discoveries of the senses to arrive at the correct expression of the principles of nature which underlie the things we observe, and which make possible all the particular phenomena we encounter. What makes Metaphysics queen of all the sciences is that it attempts to provide the organizing principles of nature and existence which can serve to guide all the other disciplines, and to show the relationships between their various principles and objects.

7. A few things about the organization of the book. Kant is well known for his systematic divisions, some of which seem to be done merely de rigueur, based on his own sense of order. I remember trying once in high school to organize a paper based on his scheme and finding it obstructive and useless. The general principle is: contents first, formal principles afterwards (or, to put it differently: matter first, then form). Thus in the Critique of Pure Reason he begins with the “Teaching on Elements” and concludes with the “Teaching on Method”. Within the former, we have first the “Aesthetic”, which discusses the principles of sensible intuition, and the “Logic”, which deals with the principles of conceptual thought. Within the Logic (by far the largest section of the Critique), we find first the Analytic, which aims to show which concepts are capable of legitimate application to experience, and then the Dialectic, which examines how they can be correctly applied. Within the Analytic, again, we have first the Analytic of Concepts, which contains two deductions meant to prove the applicability of universals to experience, and then the Analytic of Principles, which frames the basic laws that follow from the legitimate concepts he has identified for use in metaphysical reflection. Then, in the Dialectic, we have a series of chapters meant to destroy traditional metaphysics and show how not to apply the concepts and principles identified in the Analytic. The result of this organizational scheme is a tangle that is, as many students of Kant can attest, a major impediment to understanding his system of thought.

8. Kant says at the beginning of the Transcendental Logic that intuition (Anschauung) is the ultimate goal toward which all thought aims as an end. This is correct, but not in the way he intends. It is true that apprehension is the goal of all thought, and that even the acts of reasoning and judgment are instrumental uses of the intellect which aim at the distillation and perfection of what has been seen. But Kant inverts this thought: for him, the Anschauung toward which all thought aims is immediate sensible apprehension of a spatio-temporal object.  As we will see, for Kant both the spatio-temporality and the unity of the objects perceived in intuition are dependent on the mind, so that the terminus of cognition remains in the mind instead of extending to objects outside of it.  In this Kant agrees with a common presupposition of Enlightenment philosophy (both Rationalist and Empiricist), which is that ideas are the primary object of the intellect, rather than things.  This of course leads to much fretting over the Cartesian problem of whether mental ideas correspond to real objects.

9. One might say that, between the experience-centered Empiricists and idea-centered Rationalists that traded barbs across the English channel in the 17th and 18th centuries, Kant brokered a compromise by taking the worst of both camps and fusing them together. From the empiricists he took an extremely limited view of the proper scope of human understanding; from the rationalists, a confidence that the formal components of thought are, in essence, held by the mind a priori, and not extracted from experience.

Transcendental Aesthetic

10. One can see this in his work on Space and Time. To be sure, he grasps something correct about them (e.g. that our sensory experience always seems to be represented spatially), but there is also something tremendously odd about it. The first-time reader of Kant, who approaches his work with earnest docility, finds it very hard to accept that space is nothing more than the pure form projected by the mind into which our outward intuitions are received, or that time is merely a formal way of representing the succession of contradictory states of being. The Heideggerian approach to both of these things is, from the standpoint of prima facie plausibility, much nearer the mark. Unfortunately for Kant, as soon as one rejects his notion of space and time, his entire system collapses. Russell saw this, and it forms the basis of his glib dismissal of Kant in his History of Western Philosophy.

11. Even if we reject Kant’s approach to space and time on the metaphysical side of things, it lingers in the philosophy of mathematics as an interesting alternative to the popular mathematical formalism according to which the objects of math are pure conceptual constructs derivable without any reference to experience. Kant’s intuitionism about arithmetic remains compelling to me, after having made a cursory study of mathematical logic, because it retains a sense of the empirical basis of counting, a process distinct, I believe, from the convoluted analogues that have been worked up by set-theoreticians.

12. Kant’s theory of space, on the other hand, lacks both immediate plausibility and long-term coherence with science. He seems to have intended to reject Leibniz’s view of place as the relative position of extended objects, for a quasi-Newtonian view of space as an independent receptacle for objects, with the caveat that the receptacle is not absolutely infinite but indeterminate and mind-dependent, somewhat like a set of cartesian co-ordinates extended by the mind as far as is required by the graph presently being plotted. Again, from an idealist standpoint, the Heideggerian approach to space as the concern-ful distance between objects which participate in a purpose-directed environment is preferable. And from an objective, non-idealist standpoint, something like the Leibnizian position (albeit without the monads) seems correct. Space is the context determined by the relative position of material objects, and position is an accident of those objects.

Analytic of Concepts

13. The logical heart of the book comes after the section on space and time. In introducing this chapter (titled “Analytic of Concepts”), Kant explains his purpose using a famous legal metaphor, which brings us back to his story about Queen Metaphysics. When the legitimacy of a person’s possession of some title is questioned, two different issues come into play: first, the means by which the title was acquired (a question of fact); second, whether those means are sufficient to grant legitimacy to their use of it (a question of right). How did you come by this title? What sort of rights does this give you?

14. The title being contested in this trial is the primacy of metaphysics among the sciences, and particularly the legitimacy of the ordinary conceptual vocabulary of metaphysics: substance, accident, cause, effect, unity, affirmation, possibility, etc. Kant sees himself as shoring up the legitimacy of this metaphysical patrimony against the attacks of the Empiricists, and especially David Hume, who claimed that these concepts have no objective right to be applied to our experiences, but are only applied arbitrarily through custom and habit. What is interesting in this is that Kant reduces the vocabulary of metaphysics to a set of conceptual primaries, which he refers to as “Categories”, after the fashion of Aristotle. The way he goes about defeating Hume is extremely clever. He reduces the entire language of metaphysics to a basis set of twelve items, and intends, by legitimizing their use, to legitimize all the other concepts which can be derived from them by combination and application, so as to make the entire discipline of metaphysics possible again, and possible on a firm footing, with a clear sense of its foundations and legitimate extent.

15. The derivation of the particular twelve concepts (which corresponds to the question of fact, “quid facti“) is one of the weakest points of the book. Kant more or less adopts the concepts used as logical modifiers and conjunctions in judgements, based on his own understanding of logic. The logical provenance of what he refers to as “Understanding’s Logical Function in Judgments” is left unexplored and uncriticized, making this (after the treatment of Space and Time) another easy point from which to unravel his system. Once he identifies these logical functions, however, he makes a quick leap to their “categorical” versions, i.e. the metaphysical concepts which they correspond to. Thus subject and predicate correspond to substance and accident, protasis and apodosis correspond to cause and effect, and so on. After performing this transformations on the whole set of logical functions, he has a table of twelve “pure concepts of the understanding” or “categories”.

16. The main attraction of the “Analytic of Concepts” is Kant’s Transcendental Deduction of the Categories, which corresponds to the question of right or legitimacy. The argument here is given in two different forms, depending on which edition (1781 or 1787) of the text one reads. I will discuss the revised version.

17. The goal of the Transcendental Deduction is to show why the fundamental metaphysical concepts Kant has identified can legitimately be applied to experience. The basic idea is that, because, according to Hume, these concepts cannot be derived from experience, it would follow that classifying the objects of experience according to them, and making judgments about the experienced world using them are category errors: we would have no right to assume that the things under discussion are substances or have causes, so making inferences about their substantiality or causal properties would end up being a lot of senseless handwaving. Kant buys into Hume’s criticism, or what he knows of it, and tries to show that, even granted Hume’s assumption that metaphysical concepts cannot be traced to experience, it is still reasonable to use them.

18. The work in the Transcendental Deduction has several parallels to the core of Descartes’s Discourse on Method. First comes the Skeptic’s Challenge, then a foundational response to that challenge, and then a reconstruction founded on that response. And, in both cases, the lynchpin of the response is what is considered the fundamental act of the subject, the “I think”.

19. The crux of Kant’s argument is the claim that every act of analysis (for example, by which we distinguish the marks of a particular concept or definition in a judgment, or distinguish the elements in an observed external object), presupposes some prior act of synthesis which brought the various components together under a single idea. In other words, the distinction among aspects of a thing or an experience which makes judgment possible, demands that the mind have already united those various aspects in the thing in which they are being distinguished.

20. After making this claim, he asks what the original synthesis is, which makes possible all other acts of synthesis by the mind, and therefore all judgments, all connected intuitions, all experiences. He concludes that the original synthetic unity is the unity of apperception, by which all the particular concepts and representations are united under a single consciousness, in a single subject. The sign of this, he says, is the fact that every act of the mind must be capable of having “I think” appended to it, because, without this possibility, the various elements of thought could not be combined by a single subject in experiences, judgments, arguments, etc. But then, he proceeds, if the very possibility of experience and judgment presupposes the act of synthesis, then the synthetic functions by which the subject unites all of the contents of experience and thought under one consciousness, one “I think”, would apply necessarily to the contents of those experiences and thoughts, because they are, as it were, the foundation of their possibility as unities in the first place.

21. Therefore, based on the assumption that the logical functions identified earlier in the “metaphysical deduction” are, under a slightly different aspect, identical with the synthetic functions of the understanding which are the foundation for the original act of synthesis performed by the mind, it follows that these concepts are both “pure”, a priori concepts innate to the structure of the mind, and also that they are applicable to experience, since they are the tools by which the unities of experience come to be in the first place. Thus Kant has answered the Humean objection, and supplied an account of the roots of metaphysical cognition that justifies the application of normal metaphysical concepts to the objects discovered in experience. In short: metaphysics is possible, because the objects of metaphysics are constructed by the very concepts used to analyze them within metaphysics.

22. Kant’s solution to his problem is very clever, but the rest of the book shows us, step by step, how bizarre his universe ends up becoming, simply on account of the distortions he has introduced into it in order to defeat the Humean objection. Before we turn to the next part, it is worth noting the general form of Kant’s argument here, which he refers to as a “Transcendental Argument”. Transcendental arguments have the following general from: (A) We have experiences. (B) If X were not the case, then experience would be impossible. (C) Therefore, X must be the case.

23. In the case of the Transcendental Deduction of the categories, the simplified form of the argument is: (A) We have experiences. (B) If the categories were not employed by the understanding to synthesize the various contents of the mind, experience would be impossible. (C) Therefore the categories must be employed by the understanding to synthesize the various contents of the mind.

24. There are many possible objections to be made to Kant’s argumentation. We have already mentioned the frailty of the Metaphysical Deduction, but there is also the doubtful claim that synthesis always precedes analysis, the assumption that the unity of thought and experience are imposed on all our intuitions and ideas by the mind, and the failure to consider alternative psychological models which could (with less sacrifice of common sense) better account for the ordinary experience of the act of knowing. Kant’s sketch of the mechanics of the intellect is intricate and logically compelling in its own way, but it also describes a set of processes in the mind which I have never observed in myself nor could I observe. One is left wondering how he came to have such unique insights into the unknowable inner workings of human thought, and how no one prior to him seems to have had a parallel understanding of what the mind does in knowing.

Analytic of Principles

25. After finishing his work justifying the concepts of metaphysics, Kant attempts to identify the principles which govern the use of those concepts. His organization of these principles is based on the fourfold division of the categories into categories of Quantity, Quality, Relation, and Modality. Thus he identifies with principles of quantity or extensive magnitude (“Axioms of Intuition”), principles of intensive magnitude in perceptions of quality (“Anticipations of Perception), principles of relation within the objects of experience (“Analogies of Experience”), and principles of modal implication (“Postulates of Empirical Thought”).

26. Most of Kant’s principles are of little enduring interest; some contradict the dominant views held by modern science. In one section he attempts to refute theories of a void in space. Elsewhere he rejects the existence of atoms in favor of the continuous dispersion of the intensive quantity of matter. The main section of interest, for Kant and for us, is the one on substance and causation, which he calls “Analogies of Experience”. In this section, he attempts to show that experience is only possible through the synthesis of its various elements by the mind in necessary relationships.

27. In identifying the consequences of this principle, Kant’s first stop is a defense of the permanence of substance as the substratum which forms the basis of the continuity of time, and the relatability of various events experienced and understood within time. Oddly, Kant’s notion of substance is one of pure permanence: substance in his view never pass away, nor can it pass away. It merely changes as to its qualitative determinations and quantitative arrangement.

28. Furthermore, Kant defends the univocity of being, as substance. Everything real, he claims, is substance. Accidental features of substance do not have their own being, but are merely determinations of substance. Thus the arising and passing away of identifiable objects within experience is not a substantial generation or corruption, but merely the alteration of accidental features of substance. Kant’s ontology here is a materialist ontology, and therefore embraces the standard modern nominalism about natural kinds. Living things and other natural substances do not, according to the principles of Kantian metaphysics, have any real substantial unity, only an accidental unity of arrangement or harmony in their parts and characteristics.

29. The second stop in the Analogies of Experience is his famous response to Hume’s attack on the reality of causation. The argument in this reply is good and, it seems to me, logically coherent, provided one were to accept the foundations of Kant’s system (which are bizarre and unacceptable). Here he uses another transcendental argument: It is true, as Hume says, that from mere observation one cannot justify the drawing of causal relationships between different observed events, but there must be underlying relationships which justify the order of phenomena, since without such a causal ordering the sequence of events in time would be left undetermined. In order for experience, which depends on the order of phenomena within a determinate time, to be possible at all, the contents of experience must be marked with respect to their relationship within that time. Since the synthetic function within the mind which determines the necessity of events with respect to each other is causation, causation must apply to experience, since without it experience itself would be impossible.

30. At the end of the treatment of metaphysical principles, Kant sets down his understanding of modality. Possibility, he says, is coherence with the formal conditions of experience—in other words, what could be experienced, given the limitations imposed on experience by the categorical structure of the mind and the limitations of our intuitions of space and time. Actuality is coherence with the material conditions of experience—what is or will be experienced, based on the particulars of what is given in intuition. Necessity is coherence with both actuality and the universal conditions of experience. From these definitions, we see how Kant’s treatment of modality is flattened to correspond to his univocal understanding of substance: something is possible if it meets the bare requirements of experience; actual if at some point or other it matches up with those requirements in their substantial instantiation; necessary if it does both. The astute reader realizes immediately that because of his definition of necessity, Kant’s universe is purely deterministic. This is a problem he attempts to address later on in the book.

31. Before launching into a general critique of traditional metaphysics, Kant inserts a chapter on the distinction of all objects into “Phenomena” and “Noumena”. In this chapter, Kant points out one of the consequences of his treatment of the foundations of metaphysics, which will then serve as a guiding rule for his later work. Everything metaphysics can legitimately discuss is limited to the realm of possible experience, since its concepts and principles are schematized for application to spatio-temporal phenomena. Even the notions of possibility and necessity are limited in this way, so that nothing can be said to “exist”, to be possible, etc., unless it is the sort of thing that we can encounter sensibly. This means that claims about the existence of spiritual realities are completely off the table.

32. The distinction between “phenomena” which we encounter with our senses, and “noumena” which we conceive of through the unschematized (and, he thinks, illegitimate) application of the categories to things that could not possibly be experienced, raises an important question which Kant seems unwilling to confront, or even (as we will see shortly) flatly refuses to confront: what is the underlying basis of the particular realities we discover in experience? What is the basis of the thing which gives them unity? If we are prohibited from making claims about what is not sensible, how can he be justified in making so many claims about the intellectual scaffolding supporting the sensible? What is the mind? What do the forms in the mind tell us about the forms of the things which produce them? Kant declares all of these questions forbidden, and insists that we cannot answer them at all. But such a prohibition seems very flimsy when built on such an arbitrary and implausible foundation…

Transcendental Dialectic

33. Kant begins the largest section of his work with a chapter on what he refers to as “Transcendental Illusion”. Transcendental illusion is a general phenomenon which, he believes, covers the majority of ordinary metaphysical reasoning, and explains the widespread confusion and disagreement he has experienced among metaphysicians during his long career as an academic philosopher in the Leibnizian school. It occurs whenever the human mind attempts to absolutize or totalize the principles and concepts of metaphysics, and thereby takes oneself beyond the realm of possible experience into the realm of ultimates which cannot be experienced but which are thought to be the basis of what is discovered by the senses.

34. We will move relatively quickly through the next section of the work, since it is largely an application of ideas already covered. The Transcendental Dialectic attempts to deconstruct metaphysics under three headings: transcendental psychology (the study of the soul and of what might be called primary substances), transcendental cosmology (the ultimate causes, spatial limits, and temporal beginnings of the objects of experience), and rational theology (proofs of the existence of God).

35. Kant admits from the beginning that the use of reason which leads to transcendental illusion is natural and commonplace. He thinks that it is a systemic feature of human understanding that we will tend to ask the questions and perform the dialectical exercises which lead to reflections on cosmology, the soul, and God. But he also believes that he can show the inferences we make along the way to be illegitimate, both by examining them formally and by tracing out the contradictions that follow from them. This will be his approach throughout the Transcendental Dialectic.

36. The first object of Kant’s attack is philosophical psychology, and in particular proofs of the existence, simplicity, and permanence of the soul. This section has two versions, depending on the edition of the text. As before, we will look exclusively at the second edition. Here he examines proofs of the manner of existence of the soul, focusing on an argument by Moses Mendelssohn for the immortality of the soul. Kant’s reasoning can be reduced to the following: even though we observe in all our thoughts and experiences that the same “I think” is attached to them, we cannot make judgments about the substantiality or permanence of the “I”, because it is not a part of our sensible experience, and therefore is not the object of any permanent intuition which could lead us to draw conclusions about its nature. The “I” might, for example, be an accident of some other subject, or might exist in some manner which we cannot conceive of. We possess the “I” not as an object of experience, but as an intellectual given, an aspect of our thought. In this way of approaching consciousness, Kant agrees with a common materialist line: what consciousness is—whether in itself or in relation to the sensible reality of the body—we cannot conclude, but that it is a spiritual substance we certainly cannot say. Just as with contemporary materialism, Kant’s refusal to admit these questions about the ontology of the subject leads to the destruction of any understanding of the metaphysics of psychology, and therefore obstinate agnosticism about the existence and nature of the spiritual.

37. The second section of the Transcendental Dialectic seems to be Kant’s favorite. At least, he believes that the structure of this section lends credence to his system as a whole, by showing that when left to its own devices, without limitations, reason is self-contradictory. In the Antinomy of Pure Reason, he sets up four pairs of opposed arguments, each of which (he claims) validly demonstrates the inverse of the other. The arguments are organized under four heads: composition, division, origin, dependence.

38. With regard to the composition of the world as a whole, Kant claims that, according to reason, the world must be both infinite in extent (spatially and temporally) and finite. For the former he argues from the impossibility of a limit defined by nothingness, whether temporal nothingness (an empty time leading to a non-empty time) or spatial nothingness (an empty space bordering an existing space). For the latter he argues from the impossibility of an unlimited extent, whether temporally (since one would never reach the present), or spatially (since such a totality could never be conceived of — here he slips into an argument based on his own idealism). The arguments over the division of things into simple substances are analogous.

39. The third dispute is between freedom (understood, peculiarly, as the existence of spontaneous causes undetermined by nature) and determinism (understood as the necessity of all events, based on the laws of nature). He argues for the former using a debased version of St. Thomas’s first way: there must be spontaneous and non-natural causes, because otherwise the chain of natural causes would be infinite, and causation would be impossible. He argues for the latter because he claims that the existence of causes outside the order of nature would destroy causation itself.

40. The fourth dispute is over the existence of an absolutely necessary being in the universe. He argues for such a being by stating that the coherence of causation in time depends on the existence of a being in time which grounds the necessity of each successive cause. (Note that he is arguing for a being which, however it is construed, is not the same as the transcendent God we know as Christians.) He argues against such a being’s existence, whether inside the world our out of it, because that being would itself require an origin or ground of its own existence, which would just lead to the continuation of the chain.

41. It should be noted that Kant’s arguments on both sides of each question in the Antinomy are in a number of ways ill-conceived and metaphysically sloppy. We can suppose that they are examples or analogues of arguments commonly given in metaphysical disputes at the time, but this does not give one much confidence in 18th century German metaphysics.

42. After setting out all of his difficulties, Kant responds to them by showing how Transcendental Idealism removes all contradictions: space and time are potentially infinite on account of the possibility of perpetual expansion of the mind’s synthesis of representations within them as pure forms of intuition, but they are actually finite on account of the limitations of that synthesis in any particular time. Necessity must govern all experienced phenomena, but beyond the realm of possible experience there may still be some other relationship which amounts to non-natural causation, and is determinative in an un-knowable way of the entire chain of naturally determined events. Thus freedom may be preserved in some way, even though determinism must also be the case. As regards the proof of a necessary being, he rejects it because on both sides the arguments mix claims about extra-phenomenal things in themselves with claims about the nature of conditioned-ness and causation among empirical objects. Since, according to Kant, it is not allowed to apply the categories as schematized for use in experience to things which cannot be experienced, both arguments end up being sophistical equivocations.

43. The final section in the Transcendental Dialectic discusses God’s knowability through reason, or the “Ideal of Pure Reason”. Kant’s goal here is to demolish rational theology by showing how the three varieties of metaphysical proof for God’s existence (supposedly the only three that could ever exist) are fallacious. He focuses on the ontological argument, the cosmological, and the teleological (“physico-theological”).

44. His treatment of the ontological argument involves a complicated objection. The version of it he uses is similar to the version given by Descartes, and depends on the definition of God as existing, so that the statement “God does not exist” becomes self-contradictory. Kant insists that the argument fails because of a subtle equivocation on “exist”. When applied to God as a being, and not as a concept, “existence” functions as a second-order predicate, which is not a property of things but a fact of their occurrence in the world. We could examine his view on this matter further, but it seems a waste of words in the present context. To some extent, his line of thought draws near to St. Thomas’s famous account of the real composition of essence and existence in things. However, realizing this helps us see that Kant’s objection would not apply in the case of God, since here alone among all objects the identification of the thing’s existence with its characteristics is proper. Kant’s system is so far from Thomas, however, that these thoughts seem almost irrelevant.

45. Next, he turns to the cosmological argument, which he as already treated in part in the Antinomy. He claims that the cosmological argument is such an intense concatenation of sophistical propositions that it represents the apex of transcendental illusion. In other words, the cosmological argument violates all the presuppositions of his system, because it attempts to find the ground of the existence of the perceived world in something outside that world. Thus it seeks an illegitimate totality as regards the world, and terminates that totality in something of which we cannot speak or think, while applying concepts limited to phenomena to something extra-phenomenal.

46. Finally he looks at the teleological argument, also known as the argument from design or the “physico-theological” argument. His objection here is that the argument (as he frames it) would only suffice to show that an architect of the world exists, and this concept isn’t adequate to show that such a being would be supreme and divine in the way ordinarily thought. Therefore, he suggests, anyone who uses this proof is going to eventually fall back on some version of the cosmological argument to complete it.

47. Kant concludes the Transcendental Dialectic with a series of reflections on the transcendental ideas and the proper use of reason. He mocks his opponents, whom he imagines as a “rabble of subtle reasoners scream[ing] about absurdity and contradictions and rail[ing] at reason’s government.” In opposition to this rabble, he describes reason as a set of functions by which the system of human thought is united and organized, and judges that reason therefore can have no other object than human thought, and no right to consider anything beyond the architectonics of that thought. Insofar, then, as reason attempts to offer to thought a completion or totality which lies beyond its already given bounds, it creates illusions which do not deserve the title of knowledge.

48. At the end of the book, having established the elements of Metaphysics as re-founded on what Kant believes to be a secure and scientific basis, he devotes a few short chapters to the proper method of doing philosophy. These chapters are very readable, even enjoyable, and contain some general principles for carrying out mathematical demonstrations, polemics, and investigations. He describes what he understands to be the role of reason in human life, the basic questions we are tasked with answering as human beings, the different attitudes we ought to have toward cognitions with different degrees of certitude, the place of God in our aspirations, the art of constructing philosophical systems, and the history of philosophy. Among these, the section of greatest value is probably the chapter on the Architectonic of Pure Reason, in which he describes the mechanics of philosophical systems. Since systematicity is of such great importance for Kant, the reflections he gives there are illuminating for his philosophical project as a whole.

Concluding Remarks

49. Looking over the Critique of Pure Reason as a whole, the most useful element of Kant’s approach is the idea of performing a critical analysis of the origins and legitimacy of particular philosophical concepts. Not only is it essential to perform this investigation, as Kant attempts to do in a flawed way, but it is important to distinguish as he does between the investigation of the origins of our ideas in experience or thought, and their legitimacy as applied to particular objects. Though the rest of his system collapses into idealism and agnosticism, this methodological clue to restoring metaphysics remains. Those of us who wish to set philosophy back on a solid footing need to respect the empirical basis of our ideas and discern their proper range. This should be done, however, with more humility and more realism than in Kant, and without his Cartesian and Humean prejudices.  Thomists are blessed with a rich storehouse of metaphysical principles and concepts, but in an era of decline like our own, the main work of teaching these doctrines lies not in reaffirming what has been so carefully deduced by the likes of John of St. Thomas, Cardinal Cajetan, or Domingo Bañez, but in following the path of discovery from its beginning (as illuminated by such figures) and leading our own confused versions of Heraclitus and Parmenides down the path to true wisdom.