Only the real, rare, true scientific minds can endure doubt, which is attached to all our knowledge.

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.

Illusions commend themselves to us because they save us pain and allow us to enjoy pleasure instead. We must therefore accept it without complaint when they sometimes collide with a bit of reality against which they are dashed to pieces.

No other technique for the conduct of life attaches the individual so firmly to reality as laying emphasis on work; for his work at least gives him a secure place in a portion of reality, in the human community.

The intention that man should be happy is not in the plan of Creation.

This transmissibility of taboo is a reflection of the tendency, on which we have already remarked, for the unconscious instinct in the neurosis to shift constantly along associative paths on to new objects.

When one does not have what one wants, one must want what one has.