He that in the ordinary affairs of life would admit of nothing but direct plain demonstration would be sure of nothing in this world but of perishing quickly.

It is labour indeed that puts the difference on everything.

Man is not permitted without censure to follow his own thoughts in the search of truth, when they lead him ever so little out of the common road.

Curiosity should be as carefully cherish'd in children, as other appetites suppress'd.

A man may live long, and die at last in ignorance of many truths, which his mind was capable of knowing, and that with certainty.

The state of nature has a law of nature to govern it, which obliges every one: and reason, which is that law, teaches all mankind, who will but consult it.

Every man must some time or other be trusted to himself.