Two pictures, side by side. One is a virgin, one isn't. Can you tell the difference?
My dictionary defines "devil's advocate" as "one who argues against a cause or position, not as a committed opponent but simply for the sake of argument or to determine the validity of the cause or position."
I overhead a co-worker today talking about a discussion he had with project managers- "I played devil's advocate and lost."
As an aside, my dictionary does not indicate if the word's origin comes from this, but it gives a second definition as "Roman Catholic Church. An official appointed to present arguments against a proposed canonization or beatification."