Since man is not omniscient or infallible, you have to discover what you can
claim as knowledge and how to prove the validity of your conclusions. Does
man acquire knowledge by a process of reason—or by sudden revelation from a
supernatural power? Is reason a faculty that identifies and integrates the
material provided by man’s senses—or is it fed by innate ideas, implanted in
man’s mind before he was born? Is reason competent to perceive reality—or
does man possess some other cognitive faculty which is superior to reason? Can
man achieve certainty—or is he doomed to perpetual doubt? The extent of your
self-confidence—and of your success—will be different, according to which set
of answers you accept.