What praise is implied in the simple epithet useful! What reproach in the contrary.

A miracle is a violation of the laws of nature; and as a firm and unalterable experience has established these laws, the proof against a miracle, from the very nature of the fact, is as entire as any argument from experience can possibly be imagined.

It is evident, from their method of propagation, that a couple of cats, in fifty years, would stock a whole kingdom; and if that religious veneration were still paid them, it would, in twenty more, not only be easier in Egypt to find a god than a man, which Petronius says was the case in some parts of Italy; but the gods must at last entirely starve the men, and leave themselves neither priests nor votaries remaining.

The greatest crimes have been found, in many instances, to be compatible with a superstitious piety and devotion; hence it is justly regarded as unsafe to draw any inference in favor of a man's morals, from the fervor or strictness of his religious exercises, even though he himself believe them sincere.

Habit may lead us to belief and expectation but not to the knowledge, and still less to the understanding, of lawful relations.

Nothing is demonstrable, unless the contrary implies a contradiction. Nothing, that is distinctly conceivable, implies a contradiction. Whatever we conceive as existent, we can also conceive as non-existent. There is no being, therefore, whose non-existence implies a contradiction. Consequently there is no being, whose existence is demonstrable.

In all matters of opinion and science ... the difference between men is ... oftener found to lie in generals than in particulars; and to be less in reality than in appearance. An explication of the terms commonly ends the controversy, and the disputants are surprised to find that they had been quarrelling, while at bottom they agreed in their judgement.