I am always looking for good, concise ways to define science and to explain why it is key to a realistic understanding of the world around us. This recent post by Steve Novella on his blog, Neurologica, opens with a pretty good summation of science and the skeptical outlook that underlies it:
For more skepticism and science from Steve and company, I enthusiastically recommend you check out the Skeptics Guide to the Universe. It is a fun and informative podcast that covers all sorts of cool and unusual topics - from current science to skeptical thinking to evaluating paranormal claims.
There are numerous ways in which thought processes go astray, leading us to false conclusions, even persistent delusions. Skepticism, as an intellectual endeavor, is the study of these mental pitfalls, for a thorough understanding of them is the best way to avoid them.
Science itself is a set of methods for avoiding or minimizing errors in observation, memory, and analysis. Our instincts cannot be trusted, so we need to keep them in check with objective outcome measures, systematic observation, and rigid control of variables. In fact bias has a way of creeping into any observation and exerting powerful if subtle effects, leading to the need to completely blind scientific experiments. Good scientists have learned not to trust even themselves.