The inclination to aggression constitutes the greatest impediment to civilization.

Our unconscious, then, does not believe in its own death; it behaves as if it were immortal. It knows nothing that is negative; in it contradictories coincide. This may be the secret of heroism.

The unconscious - that is to say, the 'repressed' - offers no resistance whatever to the efforts of the treatment. Indeed, it itself has no other endeavour than to break through the pressure weighing down on it and force its way either to consciousness or to a discharge through some real action.

The Irish are the one race for which psychoanalysis is of no use whatsoever... because they already live in a dream world.

Religious illusion must bow to scientific truth. It is in total error about the nature of the true world. Only science is not an illusion.

The facts which have caused us to believe in the dominance of the pleasure principle in mental life also find expression in the hypothesis that the mental apparatus endeavours to keep the quantity of excitation present in it as low as possible or at least to keep it constant.

If the truth of religious doctrines is dependent on an inner experience that bears witness to the truth, what is one to make of the many people who do not have that experience?