Tis evident that all reasonings concerning matter of fact are founded on the relation of cause and effect, and that we can never infer the existence of one object from another, unless they be connected together, either mediately or immediately... Here is a billiard ball lying on the table, and another ball moving toward it with rapidity. They strike; and the ball which was formerly at rest now acquires a motion. This is as perfect an instance of the relation of cause and effect as any which we know, either by sensation or reflection.

But to proceed in this reconciling project with regard to the question of liberty and necessity; the most contentious question of metaphysics, the most contentious science.

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

Such is the nature of novelty that where anything pleases it becomes doubly agreeable if new; but if it displeases, it is doubly displeasing on that very account.

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?

When I shall be dead, the principles of which I am composed will still perform their part in the universe, and will be equally useful in the grand fabric, as when they composed this individual creature. The difference to the whole will be no greater betwixt my being in a chamber and in the open air. The one change is of more importance to me than the other; but not more so to the universe.

To invent without scruple a new principle to every new phenomenon, instead of adapting it to the old; to overload our hypothesis with a variety of this kind, are certain proofs that none of these principles is the just one, and that we only desire, by a number of falsehoods, to cover our ignorance of the truth.