Mill, seeking to prove that all our sciences, even the mathematical, have an empiric origin, brings forward the following consideration. If on every occasion that we had to take twice two things, some deity slipped one extra thing into our hands, we should be convinced that twice two is not four but five. And perhaps Mill is right: perhaps we should not divine what was the matter. We are much more concerned to discover what is practically necessary and directly useful to us than to search for truth. If a deity with each four things slipped a fifth into our hands, we should accept the additional thing and consider it natural, intelligible, necessary, impossible to be otherwise. The very uniformity in the sequence of phenomena observed by the empirical philosophers was also slipped into our hands. By whom? When? Who dares to ask? Once the law is established no one is interested in anything any more. Now we can foretell the future, now we can use the thing slipped into our hands, and the rest--cometh of the evil one. _Philosophers and Teachers_ Every one knows that Schopenhauer was for many years not only not recognised, but not even read. His books were used for waste-paper. It was only towards the end of his life that he had readers and admirers--and, of course, critics. For every admirer is at bottom a most merciless and importunate critic. He must understand everything, make everything agree, and of course the master must supply the necessary explanations. Schopenhauer, who did not have the experience of being a master till his old age, at first behaved very benevolently to his disciples' questions and patiently gave the explanations required. But the further one goes into the forest, the thicker are the trees. The most loyal perplexities of his pupils became more and more importunate, until at last the old man lost patience. 'I didn't undertake to explain all the secrets of the universe to every one who wanted to know them,' he once exclaimed, when a certain pupil persisted in emphasising the contradictions he had noticed in Schopenhauer. And really--is a master obliged to explain everything? In Schopenhauer's words we are given an answer, not ambiguous. A philosopher not only cannot be a teacher, he does not want to be one. There are teachers in schools, in universities: they teach arithmetic, grammar, logic, metaphysics. The philosopher has quite a different task, one which does not in the least resemble teaching. _Truth as a Social Substance_