WAYNE STATE UNIVERSITY
Myths of the Given and the Cogito Proof
by JOHN KING-FARLOW UNIVERSITY OF PITTSBURGH MR. ROBERT GRIM~ has recently brought a charge of circularity against Wilfrid Sellars' construction of an alternative to the Myth of the Given? While Grimm may succeed in affording an argumentum ad hominem to the phenomenalists under fire, I wish to show that some of Sellars' destructive points against the Myth as a prop of sense-datum theory can fruitfully be redeployed. I shall use them here against the specious air of logic it lends to Descartes's cog/to ergo sum. This move seems called for when A. J. Ayer and Peter Geach, in recent books 2 covering much ground treated in Sellars' demythologizing essay, have sought to refute Descartes in ways elaborate yet suspiciously inadequate. ego. This presumption turns on a disguised abuse of the Law of the Excluded Middle, an abuse I shall trace to the Myth of the Given. Consider the following structure:
Premise A: Either (I) I am deceived or (II) I am not deceived.
Warrant: The Law of the Excluded Middle. Premise B: But (I) implies that I am a thinking, experiencing, existing thing. Warrant: This (cf. Principles, I, x) turns on the very idea of experience. Premise C: And (II) likewise implies that I am a thinking, existing thing. Warrant: If my experiences are not false but veridical, then by the very idea, etc. Conclusion: Therefore I cannot but conclude that an individual T exists. Warrant: If both P and not-P imply Q, then Q. If I construe Descartes at all fairly his Cogito proof must presuppose some such appeal to the Law of the Excluded Middle as that in the Warrant for Premise A. (Otherwise it will have no serious logical force over and above the neat 'intuition' of existence in his earlier Regula III.