“The secret to humor is surprise.”

Philosophy can make people sick.

The ultimate value of life depends upon awareness and the power of contemplation rather than upon mere survival.

The aim of the wise is not to secure pleasure, but to avoid pain.

We make war that we may live in peace.

You will never do anything in this world without courage. It is the greatest quality of the mind next to honor.

The energy of the mind is the essence of life.

A friend to all is a friend to none.

Excellence is an art won by training and habituation.

Change in all things is sweet.

Knowing yourself is the beginning of all wisdom.

The soul never thinks without a mental picture.

Men acquire a particular quality by constantly acting in a particular way.

Love is composed of a single soul inhabiting two bodies.

To write well, express yourself like the common people, but think like a wise man.

Whatever lies within our power to do lies also within our power not to do.

To lead an orchestra, you must turn your back on the crowd.