“For goodness sake,' they'll cry, 'you cannot argue against it--two times two is four! Nature doesn't consult you; it doesn't give a damn for your wishes or whether its laws please or do not please you. You must accept it as it is, and hence accept all consequences. A wall is indeed a wall. ...' And so on and so forth. Good God, what do I care about the laws of nature and arithmetic if, for one reason or another, I don't like these laws, including the 'two times two is four'? Of course, I cannot break through this wall with my head if I don't have the strength to break through it, but neither will I accept it simply because I face a stone wall and am not strong enough.”