The French philosopher, Rene Descartes, is a witness in the case
You see, I began my inquiries into human understanding with some very simple questions: What do I know to be true? What is real? And it occurred to me that our senses are constantly prone to error. We see what is not there, and we don’t see what is there. Moreover, when we dream, we have no doubt that what we are experiencing is real . . .Until we wake up!! So how do I know that I am not dreaming right now? Or, perhaps it is the good people there (gesturing toward the counselors for the prosecution) who are lost in dreamland. In any case, I began my search for truth by doubting everything. And I asked myself, what is the one thing that I absolutely, positively cannot doubt? And I responded, my own existence, of course!