Rationality and Materialism according to C.S Lewis

"If the solar system was brought about by an accidental collision, then the appearance of organic life on this planet was also an accident, and the whole evolution of Man was an accident too.  If so, then all our thought processes are mere accidents-the accidental by-product of the movement of atoms.  And this holds for the materialists' and astronomers; as well as for anyone else's.  But if their thoughts are merely accidental by-products...why should we believe them to be true?  I see no reason for believing that one accident should be able to give a correct account of all the other accidents."

- C.S Lewis