It seems safe to look forward to the time when the conception of attractive and repulsive forces, having served its purpose as a useful piece of scientific scaffolding, will be replaced by the deduction of the phenomena known as attraction and repulsion, from the general laws of motion.

I wish you would let an old man, who has had his share of fighting, remind you that battles, like hypotheses, are not to be multiplied beyond necessity.

Not far from the invention of fire we must rank the invention of doubt.

Try to learn something about everything and everything about something.

My reflection, when I first made myself master of the central idea of the 'Origin', was, 'How extremely stupid not to have thought of that!'

Thoughtfulness for others, generosity, modesty, and self-respect are the qualities which make a real gentleman or lady.

If a man cannot see a church, it is preposterous to take his opinion about its altar-piece or painted window.