In Book II of the Transcendental Dialectic, Kant shifts from a general discussion of his investigation of transcendental principles as a way out of certain philosophical impasses (in Book I) (see Kant on “Transcendental Illusion” & The Proper Function of Reason and Kant on the Role of Pure Reason ) to their application. But as will soon become clear, we are now entering upon the more directly “critical” as well as dialectical phase of the Critique of Pure Reason. His primary aim is to identify not just how but where reason falls into the illusion of possessing knowledge of what it cannot know.
It is brought to accept the illusion of knowledge by entertaining inferences that are rationally sound, but lack a foundation in our potential sensory experience. In B352, for example, he equates transcendental illusion with venturing beyond the limits of potential experience as follows:
we are concerned [in the Transcendental Dialectic] only with transcendental illusion, which exerts its influence on principles that are in no wise intended for use in experience, in which case we should at least have had a criterion of their correctness, In defiance of all the warnings of criticism, it carries us altogether beyond the empirical employment of categories and puts us off with a merely deceptive extension of pure reason.”
B352
Such inferences have the defect of being purely speculative—but aren’t typically recognized as such unless they are placed under the light of skeptical empirical analysis (such as appears in Hume’s Treatise). But their speculative nature has not held their philosophical partisans back from constructing many influential philosophical systems on their basis.
For example, as will be seen, Descartes’ cogito is shown to have been the basis for many conclusions about the nature of the soul that cannot be grounded anywhere in our experience. For that reason they might be labelled “speculative,” in the pejorative sense of the term. For Kant, as may be becoming clear, it is only when our experience is brought together with pure concepts of the understanding that we can begin to have acquired an adequate foundation for the progress of knowledge.
In sum, Kant’s foundational principle for the employment of reason is that its inferences must, in principle at least, be certifiable by experience. It may be observed that this foundation for progress in acquiring knowledge curtails the speculative ponderings of traditional metaphysics and thus might be seen as congenial to the basic criteria of empirical science. As such, the door remains open for empirically grounded research and speculation: it is our possible experience that acts for him as a limit point beyond which reason cannot proceed without falling into empty speculation, the cutting edge of his philosophical critique, and a staging ground for a transcendental solution based upon what makes our possible experience possible.
In the sections that follow, Kant’s critique of pure reason eventuates in a critique of traditional and rationalistically grounded metaphysics once this criterion has been applied. Though some may lament its application, he has been able to admit a greater field for its exercise than Hume, for example, through his notion of a synthetic a priori. In any case, the spirit in which Kant carried out the Critique is more in the spirit of a critical intervention aimed at saving what may be retained of traditional metaphysics than of skepticism for its own sake.
The dialectical syllogisms mentioned in B397-8 provide an outline of the various subjects of his critique. In order, they are (1) the soul, (2) the first principle of the physical universe, and (3) the ens entium, Being itself, God as the first principle of metaphysics. Each of these topics fills the content of the succeeding chapters (the Paralogisms, the Antinomies, and the Ideal of Pure Reason) in the Critique of Pure Reason, making up the remaining “dialectical” chapters of the book which are devoted to the critique of speculative reason.
The Paralogisms of Pure Reason (A341/B399)
General Introduction to the Paralogisms
In this section Kant shows where what he calls the “rational doctrine of the soul” may be subject to his critique. It becomes clear after a few lines that the “doctrine” in question is in fact the Cartesian cogito [see B404]. What was taken to follow from the purely self-conscious (apperceptive) awareness of oneself as thinking thing, the substantiality, simplicity, personality, and personality of the soul will all fall under critical scrutiny. But above all, the important dominoes that fall are any claim to certainty about the immortality and immateriality of the soul.
The “Rationality” of the Soul
Kant explicates the term “rational” in the phrase quoted above as indicating that such a principle must lack any empirical content. If any such content were, he remarks, “intermingled with the grounds of knowledge, it would no longer be a rational but an empirical doctrine of the soul.” He goes on to say that the expression “I think,” taken in a purely rationalistic sense as indicating a pure awareness of oneself is not empirical since it is purely the subject of inner sense. But what perhaps sheds the most light upon the way he is considering the “I” of our inner perception occurs at [B401] where he writes that this rationalistically conceived self should be considered as a “universal representation of self-consciousness.” As in other cases where Kant seeks the foundations of our knowledge, the move he makes here is to consider the object of his inquiry in its logical aspect as a pure universal. In this case, the soul is considered a kind of pure quasi-generality–that is, an “I” in general lacking any specific content or any awareness of an object, including itself, since any content would serve to particularize it. Kant writes,
Consciousness is, indeed, that which alone makes all the representations to be thoughts, and in it, therefore, as the transcendental subject, all our perceptions must be found; but beyond this logical meaning of the ‘I’, we have no knowledge of the subject itself, which as substratum underlies this ‘I’, as it does all thoughts”
A350
This same way of considering a thing with regard to its pure generality might be contemplated in connection with the traditional doctrine of substance, where, by considering substance as “pure substance” it becomes a bare particular.
The Spirit of Rationalism
Kant’s discussion is so far preparatory to considering the soul as a substance. Before passing on to that argument it may be worthwhile to consider the term “rational” (still focusing on that one expression) in connection with Cartesian rationalism. The spirit in which Descartes wrote, which is also critical in spirit (restrained as it is by methodical doubt) is nevertheless animated by an adventurous, humanistic willingness to proceed wherever the light of reason might seem to show the way. The well-known caveat “but God is not a deceiver” may be taken as emblematic of his strong faith in reason [see the end of Med. V]. Consider Principle XXX in his “Principes de la Philosophie” Pt. 1 as a reflection of this spirit of rationalism (I translate):
From which it follows that the faculty which [God] has given us, which we call the natural light never perceives (apercoit) any object which is not true provided that it does in fact perceive it; that is to say, inasmuch as it knows it clearly and distinctly;
D’ou il suit que la faculte de connaitre qu’il nous a donnee, que nous appelons lumiere naturelle, n’apercoit jamais aucun objet qui ne soit vrai en ce qu’elle l’apercoit, c’est-a-dire en ce qu’elle connait clairement et distintement;
Quoted from the F. Alquie’ ed. of Oevres Philosophiques de Descartes, v. III, p. 109.
It is this kind of faith in reason that Kant will further “rationalize” by subjecting it to the critical principle discussed in the opening paragraphs above. Far from repudiating the spirit of rationalism, the notion of a pure a priori is, for Kant, the key to the discovery of the categories of thought. Nevertheless, what follows from their synthetic combination is restrained by the limits of possible experience. What matters for him is whether pure universals may be tied to experience, especially where their synthetic combination appears to be necessary for us to have any experiential knowledge of the world at all.
The Transcendental Subject
Finally, we should highlight the phrase “a transcendental subject of the thoughts =x” in B403-404. This is Kant’s restatement of the cogito in terms of his transcendental idealism. As the phrase itself begins to reveal, the “subject” in question is the rationalistic “I” (as discussed above) conceived as minimalistically as possible (as empty of any thought-content) with the variable “x” functioning as a placeholder for any object of thought, but not yet instantiated. As such, it is “completely empty,” a pure capacity or potentiality for thinking some object, so that, as he writes, it cannot even be considered a concept apart from its capacity to function as a thinking thing.
It might, in other words, be considered a “bare” apperceptive consciousness-a thing that thinks-but just that. Substance has been discussed by Allaire and others as a bare particular in a similar way as a substrate that lacks any attributes and much earlier by the “illustrious Locke,” who pointed out that when all its attributes are removed nothing empirical remains for us to consider regarding its nature. For Kant this makes the I as the bare “form of consciousness” (A382) a transcendental subject much like the categories, which he regards, like the I, as unconditioned conditions of thought (see A397).
Much like the Aristotelian account of the intellect, it may be noticed, it clearly has a purely passive element, but also an active one, its capacity to think about an object when given one. If the “=” in the phrase above is given its due weight, the “=x” suggests that the mind in a state of pure potency becomes, in a sense, its object of thought. This process of x becoming y (or more precisely, of ~t becoming t) within the substrate of our thinking consciousness we call having a thought about something is the only basis for the bare substrate I to become recognizable to itself as a thing that thinks. It can thus be said (in a way that parallels Aristotle’s de Anima) that in the act of thinking it becomes able to think of itself as a object, in this case as a thinking thing. As a pure potency, it can be reasoned, this could not occur. Only by the exercise of its potency can it become capable of thinking anything at all.
Finally, its bareness/pure potency also enters into Kant’s discussion of the unity of apperception in the Transcendental Deduction. Apperception is the I’s awareness of itself as a thing thinking about an object. In Kantian terminology, when it does so it brings its object “to the objective unity of apperception” (see the end of B 141-142). As can perhaps now be seen with greater clarity, what he has in mind here is the cognitive process of the mind having an object of thought considered in its purely logical aspect.
As discussed above, the transcendental subject in us that thinks is the subject of our thoughts. If its logical aspect is emphasized, it is the logical subject or substrate of such thoughts whenever it makes a judgment regarding its object. That judgment could be as simple as “I am aware that I think” or a textbook judgment of the form “x is y” where the I is the underlying condition of such judgments in general. It is in this sense that our thoughts enter into the unity of apperception—that is by, in a sense, entering into the judgments supported in one sense or another by our consciousness. This is the basis upon which Kant writes such things as the following:
If I investigate more precisely the relation of the given modes of knowledge in any judgment, and distinguish it, as belonging to the understanding, from the relation according to laws of the reproductive imagination, which has only subjective validity, I find that a judgment is nothing but the manner in which given modes of knowledge brought to the objective unity of apperception. This is what is intended by the copula ‘is’…. It indicates their relation to original apperception, and it’s necessary unity. It holds good even if the judgment itself is empirical, and therefore contingent, as, for example, in the judgment, ‘bodies are heavy’.”
B142 (Transcendental Deduction B)
The necessary unity of apperception is the necessity of a pre-existing (ontologically and logically prior) substrate consciousness capable of “having” a thought.
