Academic journal article The Review of Metaphysics

How Does Kant Prove That We Perceive, and Not Merely Imagine, Physical Objects? *

Academic journal article The Review of Metaphysics

How Does Kant Prove That We Perceive, and Not Merely Imagine, Physical Objects? *

Article excerpt


IN THE REFUTATION OF IDEALISM and his notes to it in the B Preface, Kant frames his antiskeptical issue in terms of proving "the reality of outer sense," which requires proving that we perceive, not merely imagine, physical objects in space and time. (1) Kant's contemporary critic Maimon reasserted the Humean objection, that the appearance of physical objects in space and time is a deceptive illusion produced by our imagination. (2) The same kind of objection is made today, for example, by Stroud, both to Kant and to his recent expositors. Maimon's objection rests on serious misunderstandings of Kant's analyses and proofs, (3) and I agree with Stroud and Rorty that recent "analytic transcendental arguments" fail to rebut (in effect) Maimon's objection. (4)

Asking how Kant proves that we perceive rather than merely imagine physical objects in space and time, presumes that Kant does prove this. This I affirm. Affirming this, however, does hot presume that Kant proved it in precisely the way he proposed. I contend that Kant's proof succeeds in ways, and to an extent, that even Kant did not appreciate. In part, this is because his proof need not appeal to transcendental idealism. Indeed, parts of Kant's proof refute his key arguments for transcendental idealism. This paper epitomizes the key steps in Kant's unofficial, though sound, transcendental proof for the conclusion of his Refutation of Idealism: namely, "The mere, though empirically determined consciousness of my own existence proves the existence of objects in space outside me." (5)


The first important point, neglected by recent reconstructions, concerns method. Recent "analytic transcendental arguments" are, of course, analytic; they attempt to justify substantive, antiskeptical conclusions by analyzing the possibility of self-conscious experience. Yet Kant stresses that no analytic argument can justify any synthetic proposition a priori. (6) If recent notions of philosophical analysis are more expansive than Kant's, they are not expansive enough to support Kant's Refutation of Idealism.

Furthermore, "analytic transcendental arguments" take as their analysandum the possibility of consciousness per se. All such arguments are refuted by Rorty's objection, that

   Arguments of the Strawsonian type rest on considerations of
   which words can be understood independently of which other words.
   The relevance of these considerations vanishes if we admit the
   possibility of a being who could experience something as an X but
   could not use the word 'X' nor any equivalent expression. (7)

However, the possibility of Rorty's imagined being would not perturb Kant at all. Kant expressly aims at identifying the transcendental conditions necessary for the possibility of human self-consciousness, and more particularly, the transcendental conditions required for us to be aware of our existence as determined in time, that is, to be aware of some events happening before, during and after others. (8) To do this, Kant engages us with a series of wildly counterfactual thought-experiments designed to bring us to recognize some of our key cognitive capacities, and their attendant incapacities. Appreciating and assessing these thought experiments involves "transcendental reflection." (9)


Kant's analysis of space and time stresses the spatio-temporality of our forms of intuition and our use of concepts of space and time in order, inter alia, to make an important semantic point about determinate reference, that is, reference to any one particular, single item. Kant stresses our incapacity to represent to ourselves the absence of space and rime. Nor can we perceive space or time as such, though of course we can conceive of their being void, or even of their being absent. (10) Kant's point concerns a key feature of the representational capacities of human beings--of out representational capacities. …

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