Michael Shermer on the history and necessity of the skepticism movement:

What’s the danger in me believing in UFOs?

Well, it starts with just, “Are you willing to believe anything?” Because if you believe your astrology column, which admittedly is relatively harmless, what else are you willing to believe?

If you have no critical facilities at all, then you’ll go for the aliens and the ESP and stuff, but then maybe you’ll accept political or economic ideologies that are equally wacky.

It really does begin with the simplest stuff.