Eckart Förster

Kant’s Refutation of Idealism

The second edition of the Critique of Pure Reason contains, according to Kant, only “one addition, strictly so called”, namely a “Refutation of Idealism”. (Bxxxix)1 It is this ‘addition’ which I want to examine in the present essay. Prima facie its very existence must astonish. For as every student of Kant knows, Kant’s solution to the “proper problem” (B19) of the Critique, that is, of how synthetic judgments are possible a priori, itself depends on an endorsement of idealism. On this point, there is no obscurity in Kant: “… the possibility of synthetic knowledge a priori… was properly the problem on the solution of which the fate of metaphysics wholly rests and to which my Critique… was entirely directed. The idealism … was… taken up into the system as the sole means of solving that problem (although it then also received confirmation from other grounds)”.2

Reply to Friedman and Guyer

I would like to begin by expressing my sincere thanks to my colleagues Friedman and Guyer for their perceptive and insightful comments on my book. Friedman’s comments I find generous and satisfying. It is, of course, always rewarding to hear laudatory comments from such an excellent Kant scholar; but I am especially pleased to notice that Friedman has now given up two views that he endorsed in his book, Kant and the Exact Sciences (1992): namely, first, his negative assessment of the ether in Kant’s Opus postumum; and, secondly, his insistence that the third Critique’s principle of a formal purposiveness of nature is nothing other than a condensed version of the three regulative principles of reason that we encounter in the Appendix to the Dialectic of the first Critique. Of the ether, Friedman now writes that its existence ‘follows from doctrines that were already developed in the first Critique, if we only take more seriously the idea that the subject of outer experience ... is itself embodied and thus located in space.’ With regard to the power of judgment’s principle of purposiveness, Friedman now concedes that it is the actual experience of natural beauty that provides us with, what he calls, ‘the fact of purposiveness,’ and, hence, with something that goes far beyond the regulative principles of reason. Indeed, it is this ‘fact of purposiveness’ in natural beauty that gives rise to judgment’s principle of a formal purposiveness of nature, and, hence, makes possible a ‘Transition from the Metaphysical Foundations of Natural Science to Physics’ as a special doctrine of critical philosophy. This last point strikes me as a particularly important one. Although there is no disagreement between Friedman and me anymore about it, I want to dwell on it a little bit, because it will allow me to illustrate what I perceive as a misunderstanding in Professor Guyer’s first objection. Guyer thinks that I locate Kant’s discovery of a principle for the Transition in the letter to Reinhold of December, 1787, where he himself cannot find anything like it: ‘It is obscure, then,’ Guyer writes, ‘just what connection between beauty and systematicity Kant might have in mind when he wrote to Reinhold.’ Guyer then proceeds to quote a passage from Kant to the effect that: since particular laws of nature are contingent from the point of view of the transcendental laws that our understanding prescribes to nature, we have