The Critical Thinker

Here's one of my favorite quotes from philosopher Harvey Seigel, offering his take on the truly critical thinker (emphasis mine; notice, too, that there are contexts in which critical thinking may not be "appropriate"):

"Such a person habitually seeks evidence and reasons, and is predisposed so to seek -- and to base belief and action on t he results of such seeking. She applies the skills and abilities of reason assessment in all appropriate contexts, including those contexts in which her own beliefs and actions are challenged."

-- Harvey Siegel, Educating Reason

Several other definitions from the website "Respectful Conversations":

Critical Thinking: Definitions - Respectful Conversation