From causes which appear similar, we expect similar effects. This is the sum total of all our experimental conclusions.

We learn the influence of our will from experience alone. And experience only teaches us, how one event constantly follows another; without instructing us in the secret connexion, which binds them together, and renders them inseparable.

Do you come to a philosopher as to a cunning man, to learn something by magic or witchcraft, beyond what can be known by common prudence and discretion?

Men are much oftener thrown on their knees by the melancholy than by the agreeable passions.

I do not think a philosopher who would apply himself so earnestly to the explaining the ultimate principles of the soul, would show himself a great master in the very science of human nature, which he pretends to explain, or very knowing in what is naturally satisfactory to the mind of man.

I know with certainty, that [an honest man] is not to put his hand into the fire, and hold it there, till it be consumed: And thisevent, I think I can foretell with the same assurance, as that, if he throw himself out at the window, and meet with no obstruction, he will not remain a moment suspended in the air.

Liberty of thinking, and of expressing our thoughts, is always fatal to priestly power, and to those pious frauds on which it is commonly founded.