Descartes was an incredibly influential figure from the Renaissance. Mostly he is influential to us, in the ways that we think and reason (whether or not we realize it). If you have heard of the terms: deductive reasoning, cartesians or I think therefore I am, than you have been influenced by Descartes. One of his philosophies derives from his desire to prove whether or not ultimate truth existed, without doubt. He concluded that his own thoughts of doubt proved that there was an actual existence, because he could not doubt that he was doubting.