Mankind are always found prodigal both of blood and treasure in the maintenance of public justice.

Avarice, the spur of industry.

Be a philosopher but, amid all your philosophy be still a man.

The life of man is of no greater importance to the universe than that of an oyster.

... superstitions, which, being unable to defend themselves on fair ground, raise these intangling brambles to cover and protect their weakness. Chased from the open country, these robbers fly into the forest, and lie in wait to break in upon every unguarded avenue of the mind, and overwhelm it with religious fears and prejudices. ... The idea of God, as meaning an infinitely intelligent, wise and good Being, arises from reflecting on the operations of our own mind, and augmenting, without limit, those qualities of goodness and wisdom.

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

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.