I didn't arrive at any cogent and clear conception of the exact relation between Kant's logical forms of judgment and his categories, and most importantly, how he derives the latter from the former.

"The same understanding - and through the same operations by which it produced, in concepts, the logical form of a judgement by means of analytuc unity - also introduces a transcendental content into its representations, by means of the synthetic unity of the manifold in intuition in general. These representations are therefore called pure concepts of the understanding applying a priori to objects" (A79, B105)

He gave this example concerning the category of community and the disjunctive logical form, which I think is really not convincing and obscure:

"...we must note that in all disjunctive judgments the sphere (...) is represented as a whole divided into parts (...), and that, as one of them cannot be contained under the other, they are thought as co-ordinated with, not subordinated to, one another...

"A similar connection is thought in a whole of things... (as, for instance, in a body the parts of which reciprocally attract and repel one another)" (B112)

We can at best talk about a certain analogy. But how can we assert the identity of the cognitive acts involved in each case?

I think I need clarification of the notions of 'judgment', 'concept', 'analytic unity', 'synthetic unity' and 'function', and how they relate in what concerns logical forms of judgment and categories.

1 Answer 1


The missing piece for you seems to be the fact that Kant builds on the idea of "architectonic" borrowed from Aristotle, as he mentions in the paragraph following the first OP quote:"Borrowing a term of Aristotle, we shall call these concepts categories, our intention being originally the same as his, though widely diverging from it in its practical application". Aristotle already "derived" a list of categories in his formal logic by classifying judgments, and Kant took Aristotle's logic as gospel, "to the present day this logic has not been able to advance a single step, and is thus to all appearance a closed and completed body of doctrine" (Preface to the second edition of CPR). So his job was merely to adapt the Aristotelian classification to his transcendental perspective. Here is an SEP commentary on how he managed it:

"Kant begins from Aristotelian logic in outlining four respects in which one can classify any judgment: according to its quantity, quality, relation, or modality. In each of these respects or ‘moments’ of judgment, there are three alternative classifications; thus, e.g., in respect of quantity, a judgment may be universal, particular, or singular; in respect of its relation, a judgment may be categorical, hypothetical, or disjunctive, and so on.

These Aristotelian ways of classifying judgments are the clue to discerning the twelve correlated concepts of the understanding. So, e.g., from noting that all judgments are either universal (e.g., All swans are white), particular (e.g., Some swans are white) or singular (e.g., Cygmund is white), we can arrive at the three corresponding categories of quantity: unity, plurality, and totality. Via this route, Kant ultimately distinguishes twelve pure concepts of the understanding (A80/B106), divided into four classes of three..."

As for the first OP quote, it rather refers to the overall scheme of the architectonic rather than the specific task of deriving categories from logic. Kant's conception of the architectonic is different from Aristotle's, where the categories are supposed to reflect the most general structures of reality (Kant borrowed the term from Baumgarten, where it had similar metaphysical meaning). In the spirit of the "Copernican revolution", it is not the categories that conform to the reality, but rather the reality is experienced in conformity with the categories. But this turning around leaves the formal category/judgment relations essentially intact, so given the forms of judgment Kant does not dwell much on deriving the categories from them. Here is an explanation of Kant's grand vision of the unifying architectonic in Friedman's Parting of the Ways, Ch.9, which I find illuminating:

"In the original Kantian architectonic, what Kant calls pure general logic (traditional Aristotelian formal logic) constitutively frames the entire system at the highest level. The traditional logical theory of concepts, judgments, and inferences supplies the formal systematic scaffolding on which Kant's comprehensive synthesis is constructed. The logical forms of concepts and judgments, when schematized by the faculty of sensibility, generate both the table of categories and the system of principles, which in turn underlie Kant's constitutive theory of human sensible experience of the phenomenal world, as made possible in pure mathematics and pure natural science.

These same logical forms, considered independently of the faculty of sensibility, then generate the concept of the noumenon, which remains merely "problematic," however, from a theoretical point of view. Further, the basic logical forms of (syllogistic) inference, again considered independently of sensibility, generate the idea of the unconditioned in general and the idea of freedom in particular. And both of these ideas also remain "indeterminate" from a theoretical point of view, although they nonetheless possess positive guiding force in the regulative use of reason. This same faculty of reason, finally, when applied to the determination of the will, also generates the moral law as a product of pure practical reason... For Kant himself, therefore, the systematic unity of all forms of thought-theoretical, practical, aesthetic, and religious - is grounded on the idea that it is ultimately the very same reason at work in all cases."

Peirce, who spent perhaps the most time analyzing Kant's derivation of the categories (three hours a day for two years, he says), and modeled his architectonic on Kant's, ended up reproaching Kant for the same thing Kant reproached Aristotle for, lack of principle:

"Kant first formed a table of various logical divisions of judgement, and then deduced his categories directly from these... The correspondences between the functions of judgement and the categories are obvious and certain. So far the method is perfect. Its defect is that it affords no warrant for the correctness of the preliminary table, and does not display that direct reference to the unity of consistency which alone gives validity to the categories."

Indeed, the parallelism between the two tables in CPR is rather transparent. The "principle" Kant claims distinguishes him from Aristotle, who "merely picked them up as they occurred to him", and provides the warrant of completeness to the categories, is in using the table of forms to derive the table of categories. But the former is ostensibly derived from syllogistic predication, not unlike Aristotle's, concepts being essentially identified with predicates. Peirce, after he learned of de Morgan's logic of relations and himself discovered detachable quantifiers, had to scrap his original list of categories, and start from scratch, see Murphey's Development of Peirce's Philosophy.

Is Aristotle's/Kant's derivation of the categories convincing? Not today. Kant vastly overestimated the completeness of his time's logical doctrines, as 19-th century logicians soon demonstrated with propositional algebra, multi-place predicates and detachable quantification. The list which seemed "exhaustive" under logic, where all one could do is predicate to a subject with glued-in quantifier, does not seem that so much anymore. To us appeals to the syllogistic seem like a mere analogy, if that, but to Kant it looked like the a priori structure of reason made flesh.

  • 2
    Thanks for your answer. But I don't think I have advanced further. You said that "Aristotle already derived an exhaustive list of categories in his logic by classifying judgements" and used this throughout your answer. But as far as I know, Aristotle didn't derive his categories from his calssification of judgements. He mentionned no such thing in the Categories, and the central point that Kant made concerning Aristotle is that "he had no guiding principle he merely picked them up as they occurred to him, and at first gathered up ten of them, which he called categories" (A81, B107)
    – Ouazzani
    Jun 17, 2017 at 16:37
  • 3
    So it's still obscure as to how he derives them and it really does require elaboration. But maybe the answer lies in that "The logical forms of concepts and judgments, when schematized by the faculty of sensibility, generate both the table of categories and the system of principles". I haven't yet reached the part concerning the schematism, so I'll see about that.
    – Ouazzani
    Jun 17, 2017 at 16:45
  • @Ouazzani I added a piece on "principle" and Kant's criticism of Aristotle. It seems to me that obscurity you point out is not so much in Kant's derivation of the categories from the forms, but in deriving the forms from his theory of cognition in a principled way. But on this he is in not much better position than Aristotle, merely "picking up" types of predication from the syllogistic. The chief justification is that thinking is bringing sensations to unity under concepts, i.e. judging, and forms of judgement are catalogued in formal logic, i.e. in the syllogistic. But why syllogistic?
    – Conifold
    Jun 21, 2017 at 0:36
  • Yes I do agree that there is the initial problem of the establishment of the table of the forms of judgments. But my question is really not about this. What I do not understand is "The correspondences between the functions of judgement and the categories". How can it be "obvious and certain" for Peirce?!
    – Ouazzani
    Jun 23, 2017 at 15:00
  • If my understanding is correct, what Kant is supposed to prove in the Metaphysical Deduction is that the twelve categories he listed are a priori concepts, and that these are the only a priori concepts we have. Given that this is not "obvious", the argument, I think, is something like this:
    – Ouazzani
    Jun 23, 2017 at 15:02

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