Lose with truth and right rather than gain with falsehood and wrong.

In the realm of Nature there is nothing purposeless, trivial, or unnecessary

It is thus necessary to examine all things according to their essence, to infer from every species such true and well established propositions as may assist us in the solution of metaphysical problems.

Your purpose...should always be to know...the whole that was intended to be known.

All forces that reside in the body are angels.

Be convinced that, if man were able to reach the end without preparatory studies, such studies would not be preparatory but tiresome and utterly superfluous.

The more necessary a thing is for living beings, the more easily it is found and the cheaper it is; the less necessary it is, the rarer and dearer it is.