A state of consciousness is characteristically very transitory; an idea that is conscious now is no longer so a moment later, although it can become so again under certain conditions that are easily brought about.

We must love or we grow ill.

The defense against childish helplessness is what lends its characteristic features to the adult's reaction to the helplessness which he has to acknowledge - a reaction which is precisely the formation of religion.

The most complicated achievements of thought are possible without the assistance of consciousness.

The division of the psychical into what is conscious and what is unconscious is the fundamental premise of psycho-analysis; and it alone makes it possible for psycho-analysis to understand the pathological processes in mental life, which are as common as they are important, and to find a place for them in the framework of science.

No one who has seen a baby sinking back satiated from the breast and falling asleep with flushed cheeks and a blissful smile can escape the reflection that this picture persists as a prototype of the expression of sexual satisfaction in later life.

The communal life of human beings had . . . a two-fold foundation: the compulsion to work, which was created by external necessity, and the power of love.