Indeed, the great Leonardo (da Vinci) remained like a child for the whole of his life in more than one way. It is said that all great men are bound to retain some infantile part. Even as an adult he continued to play, and this was another reason why he often appeared uncanny and incomprehensible to his contemporaries.

The expectation that every neurotic phenomenon can be cured may, I suspect, be derived from the layman's belief that the neuroses are something quite unnecessary which have no right whatever to exist. Whereas in fact they are severe, constitutionally fixed illnesses, which rarely restrict themselves to only a few attacks but persist as a rule over long periods throughout life.

It is unreasonable to expect science to produce a system of ethics-ethics are a kind of highway code for traffic among mankind-and the fact that in physics atoms which were yesterday assumed to be square are now assumed to be round is exploited with unjustified tendentiousness by all who are hungry for faith; so long as physics extends our dominion over nature, these changes ought to be a matter of complete indifference to you.

Nature delights in making use of the same forms in the most various biological connections: as it does, for instance, in the appearance of branch-like structures both in coral and in plants, and indeed in some forms of crystal and in certain chemical precipitates.

Were we fully to understand the reasons for other people's behavior, it would all make sense.

public self is a conditioned construct of the inner psychological self.

When it happens that a person has to give up a sexual object, there quite often ensues an alteration of his ego which can only be described as a setting up of the object inside the ego, as it occurs in melancholia; the exact nature of this substitution is as yet unknown to us.