Quand celui à qui l'on parle ne comprend pas et celui qui parle ne se comprend pas, c'est de la métaphysique
When he to whom a person speaks does not understand, and he who speaks does not understand himself, that is metaphysics.

A physician is an unfortunate gentleman who is every day required to perform a miracle; namely to reconcile health with intemperance.

But nothing is more estimable than a physician who, having studied nature from his youth, knows the properties of the human body, the diseases which assail it, the remedies which will benefit it, exercises his art with caution, and pays equal attention to the rich and the poor.

Descartes constructed as noble a road of science, from the point at which he found geometry to that to which he carried it, as Newton himself did after him. ... He carried this spirit of geometry and invention into optics, which under him became a completely new art.

Doctors are men who prescribe medicines of which they know little, to cure diseases of which they know less, in human beings of whom they know nothing. (1760)

I know of nothing more laughable than a doctor who does not die of old age.

Men argue, nature acts.

Men who are occupied in the restoration of health to other men, by the joint exertion of skill and humanity, are above all the great of the earth. They even partake of divinity, since to preserve and renew is almost as noble as to create.

Superstition is to religion what astrology is to astronomy; the mad daughter of a wise mother.

The art of medicine consists of amusing the patient while nature cures the disease.

Mock on, mock on, Voltaire, Rousseau!
Mock on, mock on: 'Tis all in vain!
You throw the sand against the wind,
And the wind blows it back again.
And every sand becomes a gem
Reflected in the beams divine;
Blown back they blind the mocking eye,
But still in Israel's paths they shine.
The atoms of Democritus
And Newton's particles of light
Are sands upon the Red Sea shore,
Where Israel's tents do shine so bright.

When I read an Italian letter [Saggio by Voltaire] on changes which had occurred on the surface of the earth, published in Paris this year (1746), I believed that these facts were reported by La Loubère. Indeed, they correspond perfectly with the author's ideas. Petrified fish are according to him merely rare fish thrown away by Roman cooks because they were spoiled; and with respect to shells, he said that they were from the sea of the Levant and brought back by pilgrims from Syria at the time of the crusades. These shells are found today petrified in France, in Italy and in other Christian states. Why did he not add that monkeys transported shells on top of high mountains and to every place where humans cannot live? It would not have harmed his story but made his explanation even more plausible.

There are some men who are counted great because they represent the actuality of their own age, and mirror it as it is. Such an one was Voltaire, of whom it was epigrammatically said: 'he expressed everybody's thoughts better than anyone.' But there are other men who attain greatness because they embody the potentiality of their own day and magically reflect the future. They express the thoughts which will be everybody's two or three centuries after them. Such as one was Descartes.