Richard Dawkings, one of the very popular atheist speaker and personality, is a INTP. In most of his video I've seen with him he demonstrate strong logic, severity, austerity and seriousness. He sharply rebuke logical flaws in his opponents, being uncompromising and sometimes absolute in his statement, leaving no room for any appeal.
He is also incredibly stuborn and strong willed...notice that the force of his personality does not rely on charisma or self-confidence, but rather a incredibly strong will in everything he does, that many times astonish people around him. That is the classic mark of INTP.
This video is a debate of Richard Dawkings with one of my favorite christians, John Lennox, a mathematician at University of Oxoford.
[video=youtube;t9t6Fkhu_MA]https://www.youtube.com/watch?v=t9t6Fkhu_MA[/video]