Previously on this blog, I've talked about what skepticism is and is not, but it's worth pointing out that much of the skepticism movement is driven by humanist principles. In his talk, Grothe defined humanism as...
HumanismWhile this is really a definition of secular humanism, it gets the point across: humanism is a set of morals and ethics based primarily (or solely) on human welfare. You can read more about humanism from the American Humanist Association (AHA), or on Wikipedia here, here, here and here.
A naturalistic (as opposed to a supernatural) ethics focused on human well being.
Grothe also takes pains points out that he's not saying "Skepticism = Atheism" nor that "Skepticism = Secular Humanism". Instead, he asserts that skepticism is both a method of inquiry, and a social movement to apply that method of inquiry towards humanistic goals (more from Grothe on skepticism starting around 11:30, and around 22:30). Good stuff, though I wish he would have gone further to draw distinctions between these and related terms like rational inquiry, which in my mind is the "method" part of skepticism separate from the social movement (although I'm not sure that is the commonly accepted meaning of the phrase).
[Hat tip to Phil Plait via Bad Astronomy]