I think that's because philosophy is like other science studies which requires a lot of critical thinking and logical reasoning, but it's always the case that we can't have certainty on the answers to the philosophical problems. That's also the reason why they have so many different schools of thoughts out there.
2007-10-19 06:27:49 補充:
However, it's not really that hard to get it once you understand how logic works, and that's why people say logic is the foundation of philosophy.