If everything must have a cause, then God must have a cause. If there can be anything without a cause, it may just as well be the world as God, so that there cannot be any validity in that argument... The idea that things must have a beginning is really due to the poverty of our imagination.

Official morality has always been oppressive and negative: it has said "thou shalt not," and has not troubled to investigate the effect of activities not forbidden by the code.

A life which goes excessively against natural impulse is... likely to involve effects of strain that may be quite as bad as indulgence in forbidden impulses would have been. People who live a life which is unnatural beyond a point are likely to be filled with envy, malice and uncharitableness.

Science is at no moment quite right, but it is seldom quite wrong, and has, as a rule, a better chance of being right than the theories of the unscientific. It is, therefore, rational to accept it hypothetically.

The demand for certainty is one which is natural to man, but is nevertheless an intellectual vice.

What men really want is not knowledge but certainty.

Meantime, the world in which we exist has other aims. But it will pass away, burnt up in the fire of its own hot passions; and from its ashes will spring a new and younger world, full of fresh hope, woth the light of morning in its eyes.