The title to one of Kant's most famous books is "Prolegomena to Any Future Metaphysics That Will Be Able to Present Itself as a Science", where he presents the outlines of his metaphysical theory further explained in Kant's Critiques.

I wondered a very simple question, did Kant considered it possible that another metaphysical theory be represented that he would consider "able to present itself as a science", or was it simply a better looking title than "Prolegomena to My Metaphysics That Presents Itself as a Science"? (or, maybe it's simply a translation "mistake"?)

I would like to note the importance of the question though, at least for me. If Kant indeed considered it possible that another metaphysical theory may present itself as science, it would mean that Kant treated his Transcendental Deduction as a possibility, rather than a final, finished, complete conception of metaphysics. Which would also separate Kant even further from Hegel on this topic, and bring him closer to Schelling. I guess there are other, probably more significant implications.

  • I am pretty sure Kant, using the broader German definition of science, and not the later English one that has ultimately taken over, considered his philosophy to be a science. The Prologomena presents the facts he thinks all such undertakings must consider, and the Critiques then undertake that considering in earnest.
    – user9166
    Aug 6, 2018 at 23:04
  • The German title is Prolegomena zu einer jeden künftigen Metaphysik, die als Wissenschaft wird auftreten können. The translation is fairly literal, Google gives "Prolegomena to any future metaphysics that will occur as science". I agree that Wissenschaft (science) narrowed its meaning since then, but note that Kant presents a meta-metaphysical framework, which reflects his epistemological turn, rather than a metaphysical theory. Like most classical philosophers Kant did of course believe that he found the "one true path" (see e.g. the CPR preface), not mere possibility, but then so did Hegel.
    – Conifold
    Aug 7, 2018 at 1:44
  • @Conifold that's exactly what I'm seeing here - Kant giving a meta-metaphysical framework, then gives a metaphysical framework within it. My question is, would Kant consider a different metaphysical theory acceptable as long as it stays within his Prolegomena's limits? It might be a bit too speculative question regarding Kant's private thoughts. Aug 7, 2018 at 5:05
  • I doubt that even access to Kant's private thoughts would give us an answer. He worked from what he had to work with in his time, but who knows how he would have reacted to subsequent developments that challenged his whole system. Kant himself flirted with "intellectual intuition" and started tweaking his framework at the end of his life, in Opus Postumum, romantics saw it as going their way. German idealists then rejected his epistemological restrictions, but neo-Kantians altered them more conservatively later.
    – Conifold
    Aug 7, 2018 at 5:47
  • @Conifold so in the scope of the Prolegomena, the German Idealists stay true to the Kantian framework, simply offering competitive metaphysical theories (like so often done in modern-day science)? Are you familiar with any correspondence of Kant's where he talks about any other metaphysical theory in a positive manner? Aug 7, 2018 at 5:58

3 Answers 3



As of metaphysics, Kant explicitly wrote that there can be other contributions and even expected them. More problematic is the question whether he expected his own transcendental philosophy, to which the transcendental deductions belong and which is a meta-metaphysics, to be revised or amended. If we take it to be a method rather than a definite content, as later Kantians did, this certainly is possible. But I would question whether Kant himself would have been open to such a view.

1. (Legitimate) metaphysics by other authors than Kant himself?

Let me quote from the introduction to the Cambridge Edition (2004), more specifically the synopsis. First from p. xxviii (all bolds are mine):

General Question (§5). Kant restates the question as: “How are synthetic propositions a priori possible?” The existence of metaphysics as science depends on a successful answer to this difficult question, which belongs to “transcendental philosophy,” a science that precedes metaphysics and determines its possibility. The “main transcendental question” is further divided into four questions: the first two respectively ask about the possibility of pure mathematics and pure natural science, the third asks about the possibility of metaphysics in general, and the fourth asks about the possibility of metaphysics as science.

So basically, the main thing he did in his Critique was transcendental philosophy, not metaphysics, i.e. the main work of filling the metaphysical gaps is not done as of yet. This is further supported later in the book (p. xxxii):

Solution to the General Question: “How is metaphysics possible as science?” (pp. 116–22). Kant asserts that it is possible only through a critique of pure reason, which must set out and analyze the entire stock of a priori concepts; which must refer such concepts to the various sources for their cognition (sensibility, understanding, reason); which must “deduce” the possibility of synthetic a priori cognition; and which must determine the principles of and the boundaries for the use of all a priori concepts. Kant hopes that the Prolegomena will excite investigation in this field, because metaphysics will not go away, given reason’s natural impulse toward metaphysical speculation.

Appendix (pp. 123–34). Kant proposes that the best route to rendering metaphysics as science actual would be a full examination of the Critique of Pure Reason. He defends the Critique against the Garve–Feder review and its charge of Berkeleyan idealism, and he proposes that the Critique and these Prolegomena be made the basis for working out a new metaphysics, limited to the principles for possible experience.

This synopsis makes clear that while he thinks to have laid the foundation for metaphysics as a science via his transcendental philosophy, there is much left to be done with regards to "metaphysics as a science". Namely, it has to be fleshed out, filled with metaphysical entities that fit within the boundaries of this new kind of critical metaphysics.

His seldomly acknowledged work Metaphysical Foundations of Natural Science as well as, obviously, the Metaphysics of Morals are two examples of that.

2. Other transcendental deductions?

This does not mean that the transcendental deductions are up to revision or alternative approaches, though: This is transcendental philosophy par excellence, i.e. meta-metaphysics. And I doubt Kant would have said that this is up to discussion.

On the other hand, the deductions are mere justifications to lift a given proposition beyond any reasonable doubt, so there is no logical reason which forbids other transcendental deductions for the same synthetic propositions a priori.

Spinning this thought further, one may think that if we see transcendental philosophy merely as a method rather than a canon of unquestionable truths, a change in the body of experience (e.g. per science) may make significant revisions necessary. This is what philosophers after Wilhelm Dilthey (historicised a priori) thought to be modern Kantianism.

As for Kant himself, I doubt this to be a possibility for him. Firstly, he thought of sciences proper as giving us necessary truths. Secondly, synthetic propositions a priori are, as the very name says, logically prior to all possible experience. He could not conceive e.g. Newton's Laws ever to be relativised and turning out to be only half of the truth. There was a great optimism in his time that science finally got hold of the deepest and eternal truths about nature.

Thus, I'd argue that while it is Kantian to allow transcendental philosophy to be seen as mere method and revise the project, including new deductions, Kant himself arguably wouldn't have been open to such "atrocities".

  • Thanks Phillip, clear and accurately outlined statement of Kant's posirion on the possibility of a science of metaphysics. One of my favorite remarks that Immanuel put on offer, I believe in the Prolegamena was something like, If you wish to do metaphysics you can either go through me and deal with the challenge laid out or ignore me and go around. (Obviously not a quote)
    – user37981
    Nov 2, 2020 at 3:49
  • I see I didn't accepted an answer here. My problem now, I want to accept both yours and GT's answers :) Nov 2, 2020 at 6:01
  • @YechiamWeiss Expanded the answer a bit on the second aspect since this was better covered by Geoff. Hope that helps!
    – Philip Klöcking
    Nov 2, 2020 at 7:53

My impression is that Kant believed that there was a single metaphysical framework in terms of which the phenomenal world and our experience of it can be represented, and that he had discovered, brought to light, the essential elements of it - even if not perfectly, then basically correctly.

I do not think that he would have regarded changes in our understanding of the world, especially as regards the nature of space and time and the notion of causality, as unhinging his enterprise. He would have recognised, as a self-critical (and incidentally scientifically well-informed) thinker, the need to revise his metaphysics to fit the new understanding. In any case, psychological speculation aside, there would have been no need to abandon the enterprise, merely to revise it.


Kant's mission was to stake out the path for speculative philosophers hoping to formulate a science of metaphysics; and for Kant, the term science reflects a priori certainty ... thus he eschews 'the magic wand of so-called common sense' as he calls it, for judging any principles of such a metaphysic. Notice in the Intro. to the Prolegomena that Kant defends David Hume, where Hume was thought by his critics to be attacking metaphysics and the concept of cause and effect, but Kant came to Hume's rescue, denounced his critics, and stated the concept of cause and effect was, just as Hume knew it to be, indispensable for metaphysics. If any metaphysic were put forth as a science, then according to Kant, it would have to be a priori reasoning through and through, from beginning to end (Kant has it that if not, then it would amount to nothing at all). He strived in his CPR to put forth an understanding of just what was called for in a science. Hegel was not the answer to Kant, at least not in the broadest sense. I'm in this sense, a strict Kantian, and Kant's demand for objective validity with regard to any science formulated a priori, on the grounds of pure reason, would have to be applicable to the world of our experience ... it would have to make sense of it. This demand is found in the CPR where Kant uses the term 'transcendental apperception' ... and it is not easily rendered intelligible, but it can be understood nonetheless.

The title of the Prolegomena suggests very much that Kant was open to the consideration of a science of metaphysics if it could address the cosmological problems he discusses in the form of the four antinomy and resolve them in the positive sense. I think it's quite apparent that he left the door open to such a possibility. See in this regard the challenge Kant issues to his Reviewer as found in the Appendix to the Prolegomena, where Kant brings up the subject of synthetic knowledge a priori. That's the crux of the whole matter where a science is concerned. It cannot be mere guesswork or conjecture. It is also for this reason that Kant speaks of mathematics as an example of a priori knowledge ... it's abstract, but certain; and so any science of metaphysics would also have to be abstract, a priori in conceptualization. There's much more that can be said.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .