he was in fact committed to people questioning assumptions , throwing aside old superstitions , breaking the shackles of irrational prejudice and , in short , exercising the brains their god had given them , except of course they had n't been given them by any god , lord knows , so what they really ought to do was exercise those brains developed over millennia in response to the external stimuli and the need to control those hands with their opposable thumbs , another damn good idea that he was very proud of .