We should picture the instrument that carries our mental functioning as resembling a compound microscope or photographic apparatus.

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.

A state of consciousness is characteristically very transitory; an idea that is conscious now is no longer so a moment later, although it can become so again under certain conditions that are easily brought about.

Pathology has made us acquainted with a great number of states in which the boundary lines between the ego and the external world become uncertain or in which they are actually drawn incorrectly. There are cases in which parts of a person's own body, even portions of his own mental life - his perceptions, thoughts and feelings -, appear alien to him and as not belonging to his ego; there are other cases in which he ascribes to the external world things that clearly originate in his own ego and that ought to be acknowledged by it.

The study of dreams may be considered the most trustworthy method of investigating deep mental processes. Now dreams occurring in traumatic neuroses have the characteristic of repeatedly bringing the patient back into the situation of his accident, a situation from which he wakes up in another fright.

Thus we arrive at the singular conclusion that of all the information passed by our cultural assets it is precisely the elements which might be of the greatest importance to us and which have the task of solving the riddles of the universe and of reconciling us to the sufferings of life -- it is precisely those elements that are the least well authenticated of any.

Incidentally, why was it that none of all the pious ever discovered psycho-analysis? Why did it have to wait for a completely godless Jew?