Anyone who wants to know the human psyche will learn next to nothing from experimental psychology. He would be better advised to abandon exact science, put away his scholar's gown, bid farewell to his study, and wander with human heart through the world.

Once upon a time men were possessed by devils. Now they are not less obsessed by ideas

When facts are few, speculations are most likely to represent individual psychology.

Not only does the psyche exist, but it is existence itself. It is an almost absurd prejudice to suppose that existence can only be physical...We might well say, on the contrary, that physical existence is a mere inference, since we know of matter only in so far as we perceive psychic images mediated by the senses.

The sure path can only lead to death.

You must live life in such a spirit that you make in every moment the best of possibilities.

The pendulum of the mind alternates between sense and nonsense, not between right and wrong.