The people on their part may think that cognition is knowing all about things, but the philosopher must say to himself: When I analyze the process that is expressed in the sentence, 'I think,' I find a whole series of daring assertions, the argumentative proof of which would be difficult, perhaps impossible: for instance, 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 is to be designated by thinking that I what thinking is.