Iron rusts from disuse; water loses its purity from stagnation... even so does inaction sap the vigor of the mind.

The function of muscle is to pull and not to push, except in the case of the genitals and the tongue.

Truth at last cannot be hidden. Dissimulation is of no avail. Dissimulation is to no purpose before so great a judge. Falsehood puts on a mask. Nothing is hidden under the sun.

For those colours which you wish to be beautiful, always first prepare a pure white ground.

Supreme happiness will be the greatest cause of misery, and the perfection of wisdom the occassion of folly.

Where there is most feeling, there is the greatest martyrdom.

All our knowledge hast its origins in our perceptions … In nature there is no effect without a cause … Experience never errs; it is only your judgments that err by promising themselves effects such as are not caused by your experiments … Science is the observation of things possible, whether present or past; prescience is the knowledge of things which may come to pass.