A Quote by Sigmund Freud on spirit, life, development, and breath

Man found that he was faced with the acceptance of "spiritual" forces, that is to say such forces as cannot be comprehended by the senses, particularly not by sight, and yet having undoubted, even extremely strong, effects. If we may trust to language, it was the movement of the air that provided the image of spirituality, since the spirit borrows its name from the breath of wind (animus, spiritus, Hebrew: ruach = smoke). The idea of the soul was thus born as the spiritual principle in the individual ... Now the realm of spirits had opened for man, and he was ready to endow everything in nature with the soul he had discovered in himself.