I am sure many of you have heard, or perhaps even used the term, skeptic. It is often associated with a person who does not believe in something. That is, in general, the correct usage of the word, but there is more to a true skeptic.

Skepticism is a belief system that basically states that we can not truly know anything. There are essentially 5 parts to the skeptics proof that there is no true knowledge in the world. First is that knowledge must come from reason or sense, but it is better to suppose neither work since each contradict each other. Secondly, no truth can be demonstrated since all truths are dependent upon the proof on another, causing an infinite loop of proofs relying on other proofs leading no where. Thirdly, reason is relative to reasonable being and sense experience is relative to sensing being, thus there is no reason to prefer one over the other since they rely upon something. The fourth point is that self-evident truths do not exist since they require outside proofs, thus negating there self-evidence. And lastly, senses can not be proven by reason since reason must be proven by senses.

You can essentially argue against skepticism in different ways. Socrates used the dialectic method of discussion which is essentially a dialogue back and forth until a definition is reached. He would then have a discussion with a skeptic and have a point against them, and that would go back in forth in hopes of reaching truth. Of course the skeptic would not believe since there is no truth, but then skepticism can't be true either since that would be a truth. So skepticism is self-defeating by its own definition.