In the article we argue that Descartes while considering sign version of cogito does use some hidden premises in spite of well-known declaration there are none. They are:1) there’s such a length of time Δt over which I cannot be wrong on the matter of what happened over Δt (infallible time); 2) there’s such time extent Δt upon which I cannot be wrong (say, if an event happened quickly from I-viewpoint then while being measured in some standard units, one will appraise it as“quickly” as well). We investigate the advantages the evil demon can take from that. This is a sign manipulation we propose. Cogito as a sign object has to have a) a sense-data component and b) can be built only through time by consecutive generation one elementary sign after another. Then an (elementary) sign manipulation is the following: (1) I is [not am] building the sign si(or some part of it, which is not a sign any longer), (2) I thinks wrongly that the previous signs just built are s1, …, si-1 (the evil demon’s work), (3) I is [not am] going to built signs si+1, …, sn. For example, one thinks of self as thinking cogito, while in fact the real event is building “t” (the part “cogi” being prior to “t” is in the past and as such can be manipulatively substituted instead of what really happened in the life of I before building the sign “t” (whatever it is; probably, nothing; probably, I didn’t exist before generating “t”)). We investigate the source which makes the manipulation possible and the gravity of the destruction of such sort. The crucial reason for the possibility of such misconception turns out to be the sense-data component in any linguistic (being sign) constructions.

Contemporary Philosophy | Philosophy of Science