No one can be a great thinker who does not recognise, that as a thinker it is his first duty to follow his intellect to whatever conclusions it may lead. [Mill, On Liberty, chapter II, par. 20.]
I think of Socrates and Otto Weininger, the only two philosophers I know of whose deaths were a direct consequence of their philosophical convictions. (If we exclude Peregrinus, the ancient cynic, who leaped into a bonfire to make a point during one of the early Olympic games. He was probably disgusted by the corruption even then.)
I imagine Weininger in a gun shop in Vienna. The clerk asks, “What does a philosopher do with a gun?”