You don't get into trouble because of the things you don't know. It is the things you don't know you don't know that really get you into a mess.

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

In whatever system where the weight attached to the wheel should be the cause of motion of the wheel, without any doubt the center of the gravity of the weight will stop beneath the center of its axle. No instrument devised by human ingenuity, which turns with its wheel, can remedy this effect. Oh, speculators about perpetual motion, how many vain chimeras have you created in the like quest. Go and take you place with the seekers after gold.

Test knowledge through experience, be prepared to make mistakes, and be persistent about it.

Patience serves as a protection against wrongs as clothes do against cold. For if you put on more clothes as the cold increases, it will have no power to hurt you. So in like manner you must grow in patience when you meet with great wrongs, and they will then be powerless to vex your mind.

Depth and strength of a human character are defined by its moral reserves.

Black is like a broken vessel, which is deprived of the capacity to contain anything.