Even if all parts of a problem seem to fit together like the pieces of a jigsaw puzzle, one has to remember that the probable need not necessarily be the truth and the truth not always probable.

We have become convinced that it is better to avoid such symbolic disguisings of the truth in what we tell children and not to withhold from them a knowledge of the true state of affairs commensurate with their intellectual level.

The fateful question for the human species seems to me to be whether and to what extent their cultural development will succeed in mastering the disturbance of their communal life by the human instinct of aggression and self-destruction ... One thing only do I know for certain and that is that man's judgements of value follow directly from his wihes for happiness-that, accordingly, they are an attempt to support his illusions with arguments.

In the theory of psycho-analysis we have no hesitation in assuming that the course taken by mental events is automatically regulated by the pleasure principle. We believe, that is to say, that the course of those events is invariably set in motion by an unpleasurable tension, and that it takes a direction such that its final outcome coincides with a lowering of that tension that is, with an avoidance of unpleasure or a production of pleasure.

One is very crazy when in love.

Man has, as it were, become a kind of prosthetic God. When he puts on all his auxiliary organs, he is truly magnificent; but those organs have not grown on him and they still give him much trouble at times.

Love can not be much younger than the lust for murder.