Prayer is to the spiritual life what the beating of the pulse and the drawing of the breath are to the life of the body.

From the age of fifteen, dogma has been the fundamental principle of my religion: I know no other religion; I cannot enter into the idea of any other sort of religion; religion, as a mere sentiment, is to me a dream and a mockery.

God knows what is my greatest happiness, but I do not. There is no rule about what is happy and good; what suits one would not suit another. And the ways by which perfection is reached vary very much; the medicines necessary for our souls are very different from each other. Thus God leads us by strange ways; we know He wills our happiness, but we neither know what our happiness is, nor the way. We are blind; left to ourselves we should take the wrong way; we must leave it to Him.

We must make up our minds to be ignorant of much, if we would know anything.

When men understand what each other mean, they see, for the most part, that controversy is either superfluous or hopeless

A science is not mere knowledge, it is knowledge which has undergone a process of intellectual digestion. It is the grasp of many things brought together in one, and hence is its power; for, properly speaking, it is Science that is power, not Knowledge.

To live is to change, and to be perfect is to have changed often.