To those who inquire as to the purpose of mathematics, the usual answer will be that it facilitates the making of machines, the travelling from place… - Bertrand Russell

The wise man will be as happy as circumstances permit, and if he finds the contemplation of the universe painful beyond a point, he will contemplate something else instead.

I should like to believe my people's religion, which was just what I could wish, but alas, it is impossible. I have really no religion, for my God, being a spirit shown merely by reason to exist, his properties utterly unknown, is no help to my life. I have not the parson's comfortable doctrine that every good action has its reward, and every sin is forgiven. My whole religion is this: do every duty, and expect no reward for it, either here or hereafter.

[T]he philosophy of Plotinus has the defect of encouraging men to look within rather than to look without: when we look within we see nous, which is divine, while when we look without we see the imperfections of the sensible world. This kind of subjectivity was a gradual growth; it is to be found in the doctrines of Protagoras, Socrates, and Plato, as well as in the Stoics and Epicureans. But at first it was only doctrinal, not temperamental; for a long time it failed to kill scientific curiosity. [...] Plotinus is both an end and a beginning—an end as regards the Greeks, a beginning as regards Christendom.