Beyond Good and Evil by Friedrich Nietzsche Chapter 6 Page 40

TO POWER. — Are there at present such philosophers? Have there ever been such philosophers? MUST there not be such philosophers some day? ...

212. It is always more obvious to me that the philosopher, as a man INDISPENSABLE for the morrow and the day after the morrow, has ever found himself, and HAS BEEN OBLIGED to find himself, in contradiction to the day in which he lives; his enemy has always been the ideal of his day. Hitherto all those extraordinary furtherers of humanity whom one calls philosophers — who rarely regarded themselves as lovers of wisdom, but rather as disagreeable fools and dangerous interrogators — have found their mission, their hard, involuntary, imperative mission (in the end, however, the greatness of their mission), in being the bad conscience of their age.