There is to my mind no doubt that the concept of beautiful had its roots in sexual excitation and that its original meaning was sexually stimulating.

I think that in general it is a good plan occasionally to bear in mind the fact that people were in the habit of dreaming before there was such a thing as psychoanalysis.

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.

I became aware of my destiny: to belong to the critical minority as opposed to the unquestioning majority.

An intimate friend and a hated enemy have always been indispensable requirements for my emotional life; I have always been able to create them anew, and not infrequently my childish ideal has been so closely approached that friend and enemy coincided in the same person.

When making a decision of minor importance, I have always found it advantageous to consider all the pros and cons. In vital matters, however, such as the choice of a mate or a profession, the decision should come from the unconscious, from somewhere within ourselves. In the important decisions of personal life, we should be governed, I think, by the deep inner needs of our nature.

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.