How Is Metaphysics as a Science Possible? Kant on the Distinction between Philosophical and Mathematical Method

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METAPHYSICS AS A SCIENCE AND THE ANALYTIC-SYNTHETIC DISTINCTION. In his important study on Kant and the exact sciences, Michael Friedman argues rather convincingly that "much of Kant's philosophical development can be understood, . . . as a continuous attempt to construct. . . a genuine metaphysical foundation for Newtonian natural philosophy."(1) Kant started his philosophical career as an adherent of what used loosely to be called Leibnizian-Wolffian metaphysics; but he became increasingly more skeptical of the possibility of reconciling this metaphysics with the exact sciences of his day. It was largely this conflict-ridden confrontation that brought Kant in the end to a radical break with Leibnizian-Wolffian metaphysics. The critical Kant is out to find a better successor for this dogmatic--because uncritical--metaphysics. Not last among Kant's concerns in these matters is the status of metaphysics as a theoretical science. For he realises that the very nature of this discipline presents a thinker with substantial problems; a great deal of preliminary work will have to be done before a metaphysics can appear that satisfies all the demands of a real science. The Kritik der reinen Vernunft should be viewed and understood in this context:

[The] attempt to alter the procedure which has hitherto prevailed in

metaphysics, by completely revolutionising it in accordance with the

example set by the geometers and physicists, forms indeed the main

purpose of this critique of pure speculative reason. It is a treatise on

the method, not a system of the science itself. But at the same time it

marks out the whole plan of the science, both as regards its limits and

as regards its entire internal structure.(2)

In other words, the first Kritik is at least partly a work on the methodology (or logic) of metaphysics.(3) Kant claims to have opened the way with this study for "any future metaphysics that will be able to present itself as a science," as the subtitle of the Prolegomena has it.

Where the possibility of metaphysics as a science is concerned, Kant assigns the exact sciences the function of an exemplar; for these disciplines have long been well established on "the secure path of a science."(4) Accordingly, in the Prolegomena Kant explicitly addresses the question "How is metaphysics possible as a science?" by way of the questions "How is pure mathematics possible?" and "How is pure natural science possible?"(5) Moreover, all these questions arise directly out of the main transcendental question: "How are synthetic judgments a priori possible?" The deplorable situation of the metaphysics of the day would have been entirely attributable to misappraisal of this central transcendental question.(6)

Yet from the Kritik a different picture arises that at first glance does not seem to rhyme with the exemplary image of the exact sciences, in particular mathematics. For in the last part of this work, which deals with the transcendental doctrine of method, Kant presents an extensive comparison of the method of mathematics with that of philosophy or, as the case would have it, metaphysics. The result of this comparison is somewhat surprising, however. For there Kant arrives at the conclusion

that mathematics and philosophy, . . ., are none the less so completely

different, that the procedure of the one can never be imitated by the

other.(7)

The philosopher should take precisely no notice of the method of the mathematician as an example. Use of the mathematical method in the field of metaphysics would only result in "houses of cards."

E. W. Beth once noted that the chapter from the Kritik in which Kant contrasts the method of mathematics with that of philosophy contains a number of passages that are strongly reminiscent of the pre-critical Untersuchung uber die Deutlichkeit der Grundsatze der naturlichen Theologie und der Moral; this little work first appeared in 1764, but it was written a year earlier. …