When i analyze the process that is expressed in the sentence, "I think," I find a whole series of daring assertions that would be difficult, perhaps impossible to prove; for example, that it is I who think, that there must necessarily be something that thinks, that thinking is an activity and operation on the part of a being who is thought of as a cause, that there is an "ego," and, finally, that it is already determined what it is to be designated by thinking-that I know what thinking is. For if I had not already decided within myself what it is, by what standard could I determine whether that which is just happening is not perhaps "willing" or "feeling"? In short, the assertion "I think" assumes that I compare my state at the present moment with other ststes of myself which I know, in order to determine what it is; on account of this retrospective connection with further "knowledge," it has, at any rate, no immediate certainty for me.
