When a man is prey to his emotions, he is not his own master.

I make this chief distinction between religion and superstition, that the latter is founded on ignorance, the former on knowledge.

Freedom is self-determination.

Nothing comes to pass in nature, which can be set down to a flaw therein; for nature is always the same, and everywhere one and the same in her efficacy and power of action: that is, nature's laws and ordinances, whereby all things come to pass and change from one form to another, are everywhere and always the same; so that there should be one and the same method of understanding the nature of all things whatsoever, namely, through nature's universal laws and rules.

Only that thing is free which exists by the necessities of its own nature, and is determined in its actions by itself alone.

The mind has greater power over the emotions, and is less subject thereto, insofar as it understands all things to be necessary.

Yet nature cannot be contravened, but preserves a fixed and immutable order.