Necessarily, that which is experienced is experienced. The belief that one merely thinks is experiencing something but is actually mistaken is untenable. The qu

Necessarily, that which is experienced is experienced. The belief that one merely thinks is experiencing something but is actually mistaken is untenable. The question is whether the feeling of these keys under what I think are my fingers is caused by something that exists more or less as I perceive it, rather than some contrived hallucination or an illusion. But I'm not able to doubt that I am in fact feeling what I feel. Besides mathematical truths, it's all I can be certain of.