The Human Condition (book) but the self, Descartes and other moderns thought, could be known. Though his cogito ergo sum was anticipated by Augustine, his dubito ergo sum is original and a hallmark of modernity: beginning from doubt. The notion of common sense as a sense in which the other five were fitted to a common world ceded to a conception of common sense as an inner faculty with no relationship to the world, and the assumption that all humans had faculties like this in common became necessary to get theories going, but without the assumption of a common world, the assumption of faculties
Cogito, ergo sum the "I" from the thinking thing. Here, the "cogito" has already assumed the "I"'s existence as that which thinks. For Kierkegaard, Descartes is merely "developing the content of a concept", namely that the "I", which already exists, thinks. As Kierkegaard argues, the proper logical flow of argument is that existence is already assumed or presupposed in order for thinking to occur, not that existence is concluded from that thinking. Bernard Williams claims that what we are dealing with when we talk of thought, or when we say "I am thinking," is something conceivable from a third-person perspective; namely objective "thought-events"