Descartes [the French philosopher] sought to doubt every thought that came into his head (e.g., is he really eating an apple or only dreaming that it is so?) until he would come upon something which was indubitable. Systematic doubt would open the door to final certainty for him. Yet Descartes recognized that he could not ultimately doubt everything…
The modern-day apes of Descartes who claim they will doubt absolutely everything and accept nothing, except upon proof act or talk like arrogant fools. Nobody can doubt everything. Nobody. If a person were truly to doubt everything—his memory of past experiences, his present sensations, the “connections” between experiences, the meanings of his words, the principles by which he reasons—he would not be “thinking” at all (much less doubting), and there would be no “he” to think or not to think. A fundamental (logically basic) set of beliefs—a faith—is inescapable for anyone.
Men only succeed in deluding themselves when they say that they will not accept anything without proof or demonstration—that they allow no place for “faith” in their outlook or in the living of their lives. Accordingly, such unbelievers who criticize Christians for appealing to “faith” are intellectual hypocrites—men who cannot and do not live by their own declared standards for reasoning.
–Greg. L. Bahnsen,