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?

Weakness, fear, melancholy, together with ignorance, are the true sources of superstition. Hope, pride, presumption, a warm indignation, together with ignorance, are the true sources of enthusiasm.

Nothing indeed can be a stronger presumption of falsehood than the approbation of the multitude.

If we confine ourselves to a general and distant reflection on the ills of human life, that can have no effect to prepare us for them. If by close and intense meditation we render them present and intimate to us, that is the true secret for poisoning all our pleasures, and rendering us perpetually miserable.

Morals and criticism are not so properly objects of the understanding as of taste and sentiment.

What a peculiar privilege has this little agitation of the brain which we call 'thought'.

It seems certain, that though a man, in a flush of humour, after intense reflection on the many contradictions and imperfections of human reason, may entirely renounce all belief and opinion, it is impossible for him to persevere in this total scepticism, or make it appear in his conduct for a few hours.