I think therefore I am.
Descartes sought to prove the existence of “I” without presupposition.
1.)
P1: I think
C: I exist
This argument seems to presuppose the existence of “I” before the inference. This is a problem if “I” denotes all the qualities and characteristics that make up one’s personal identity. “I” could simply denote the phenomenon of the experience of thinking (see argument 3).
2.)
P1: I think
P2: All things that think, exist
C: I exist
Adding the suppressed premise does not help with the presupposition of “I.”
3.)
P1: Something thinks
P2: All things that think, exist
C: Some thinking thing exists
This argument avoids the problem of presupposing “I,” but subverts a substantive conclusion by doing so. “The thing” it proves to exist has only one certain property (it thinks). This might be the only sound deductive formulation of the Cogito. Using this conclusion, one can easily induce that the thinking thing has all the familiar properties of “I.”
Further attempts at a deduction are welcome.
