He who is fixed to a star does not change his mind.

The painter who has no doubt about his own ability will attain very little.

The days are long enough for those who use them.

Whatever you do in life, if you want to be creative and intelligent, and develop your brain, you must do everything with the awareness that everything, in some way, connects to everything else.

One has no right to love or hate anything if one has not acquired a thorough knowledge of its nature. Great love springs from great knowledge of the beloved object, and if you know it but little you will be able to love it only a little or not at all.

Those who fall in love with practice without science are like a sailor who enters a ship without a helm or a compass, and who never can be certain whither he is going.

Medicine is the restoration of discordant elements.