Answer:
It means pretend or make believe.
Step-by-step explanation:
In this famous passage from Descartes´ Discourse, he has reached a point in his argument where he recognizes that he can doubt just about everything that his senses and his mind inform him of, except the very fact that he is doubting; and, if he is doubting, no doubt there must be someone or something that is doing this action of doubting, therefore, that something or someone must by necessity exist. At this point, Descartes confesses that he can “pretend” to continue doubting everything, but there is one thing that he cannot in any way pretend to doubt any more, and that is: I think, therefore I am.