Poor Descartes, imagining that everything on which he had built his life was coming under doubt. Every footing that he had held as solid foundation on which to base thought and decision was disintegrating. It may seem hard to relate to that, but maybe I do have experience that can, in a small way, reflect his. Of course, he had to deal with impending torture of the body and damnation of the soul if his thought did not meet with approval from his audience.

Descartes was attempting to find a solid basis for knowledge by supposing that everything he had learned, or was able to observe through his senses, was doubtful. As he descended further and further into this progressive, methodological doubt he rejected layer after layer that which he had previously held to be true. Eventually, he remained sure of one thing, the famous phrase, cogito ergo sum, I think therefore I am. In his Meditations (Descartes, 1641/1901), he came out of his doubt by ascribing the only possible proof of knowledge to mathematics, and the reduction of any problem to its smallest possible piece. His meditations also sought to prove the existence of God through this process; if he had not, he would have had to face the Inquisition and excommunication that in those times insinuated his eternal damnation.