In action, in desire, we must submit perpetually to the tyranny of outside forces; but in thought, in aspiration, we are free, free from our fellowmen, free from the petty planet on which our bodies impotently crawl, free even, while we live, from the tyranny of death.

It appeared to me obvious that the happiness of mankind should be the aim of all action, and I discovered to my surprise that there were those who thought otherwise.

Science, in its ultimate ideal, consists of a set of propositions arranged in a hierarchy, the lowest level of the hierarchy being concerned with particular facts, and the highest with some general law, governing everything in the universe. The various levels in the hierarchy have a two-fold logical connection, travelling one up, one down; the upward connection proceeds by induction, the downward by deduction.

All the conditions of happiness are realized in the life of the man of science.

It is essential to happiness that our way of living should spring from our own deep impulses and not from the accidental tastes and desires of those who happen to be our neighbors, or even our relations.

The moral thing I should wish to say to them is very simple; I should say: "Love is wise - Hatred is foolish." In this world, which is getting more and more closely interconnected, we have to learn to tolerate each other.

Aristotle, in spite of his reputation, is full of absurdities. He says that children should be conceived in the Winter, when the wind is in the North, and that if people marry too young the children will be female. He tells us that the blood of females is blacker than that of males; that the pig is the only animal liable to measles; that an elephant suffering from insomnia should have its shoulders rubbed with salt, olive-oil, and warm water; that women have fewer teeth than men, and so on. Nevertheless, he is considered by the great majority of philosophers a paragon of wisdom.