The philosopher forms his principles on an infinity of particular observations. He does not confuse truth with plausibility, he takes for truth what is true, for false what is false, for doubtful what is doubtful, and probable what is probable. The philosophical spirit is thus a spirit of observation and accuracy.

When we know to read our own hearts, we acquire wisdom of the heartsof others.

Whatever dressing one gives to mushrooms, to whatever sauces our Apiciuses put them, they are not really good but to be sent back to the dungheap where they are born.

All things must be examined, debated, investigated without exception and without regard for anyone's feelings... We must run roughshod over all these ancient puerilities, overturn the barriers that reason never erected, give back to the arts and sciences the liberty that is so precious to them.

What is this world? A complex whole, subject to endless revolutions. All these revolutions show a continual tendency to destruction; a swift succession of beings who follow one another, press forward, and vanish; a fleeting symmetry; the order of a moment. I reproached you just now with estimating the perfection of things by your own capacity; and I might accuse you here of measuring its duration by the length of your own days.

In order to get as much fame as one's father one has to much more able than he.

There's a bit of testicle at the bottom of our most sublime feelings and our purest tenderness.