Of learned men, the clergy show the lowest development of professional ethics. Any pastor is free to cadge customers from the divines of rival sects, and to denounce the divines themselves as theological quacks.

The notion that science does not concern itself with first causes - that it leaves the field to theology or metaphysics, and confines itself to mere effects - this notion has no support in the plain facts. If it could, science would explain the origin of life on earth at once - and there is every reason to believe that it will do so on some not too remote tomorrow. To argue that gaps in knowledge which will confront the seeker must be filled, not by patient inquiry, but by intuition or revelation, is simply to give ignorance a gratuitous and preposterous dignity.

It is the mission of the pedagogue, not to make his pupils think, but to make them think right, and the more nearly his own mind pulsates with the great ebbs and flows of popular delusion and emotion, the more admirably he performs his function. He may be an ass, but that is surely no demerit in a man paid to make asses of his customers.

A poet more than thirty years old is simply an overgrown child.

I know of no existing nation that deserves to live, and I know of very few individuals.

In any combat between a rogue and a fool the sympathy of mankind is always with the rogue.

Friendship is a common belief in the same fallacies, mountebanks and hobgoblins.