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.

Avarice, or the desire of gain, is a universal passion which operates at all times, at all places, and upon all persons.

In ancient times, bodily strength and dexterity, being of greater use and importance in war, was also much more esteemed and valued, than at present. ... In short, the different ranks of men are, in a great measure, regulated by riches.

Examine the religious principles which have, in fact, prevailed in the world. You will scarcely be persuaded that they are other than sick men's dreams.

Enthusiasm, being the infirmity of bold and ambitious tempers, is naturally accompanied with a spirit of liberty; as superstition,on the contrary, renders men tame and abject, and fits them for slavery.

When men are most sure and arrogant they are commonly most mistaken.

Nothing is pure and entire of a piece. All advantages are attended with disadvantages. A universal compensation prevails in all conditions of being and existence.