Inaction saps the vigor of the mind.

The mole has very small eyes and it always lives under ground; and it lives as long as it is in the dark but when it comes into the light it dies immediately, because it becomes known;--and so it is with lies.

Ask counsel of him who rules himself well.

Truth was always but the daughter of time.

Not to appreciate life, all of life, is not to deserve it.

There is no result in nature without a cause; understand the cause and you will have no need of the experiment.

Necessity is a guardian in Nature.