To Ernst Hanhart
Dear Colleague, 18 February 1957
Very many thanks for kindly sending me your offprint, which I have read with great interest.
The fate of children born of incest was most interesting and instructive.
With regard to your questions, I much regret that I am no longer in a position to see you personally.
Your letter arrived at the moment of my departure.
The question of the identity of psychological and physiological types is a complicated one.
Kretschmer's type are based primarily on somatic criteria.
My typology is based exclusively on psychological premises which can hardly coincide with physiological or somatic qualities.
Somatic characteristics are permanent and virtually unalterable facts, whereas psychological ones are subject to various alterations in the course of personality development and also to neurotic disturbances.
Even though assignment to a particular type may in certain cases have lifelong validity, in other very frequent cases it is so dependent on so many external and internal factors that the diagnosis is valid only for certain periods of time.
Freud was just such a case.
On the basis of an accurate knowledge of his character, I consider him to have been originally an introverted feeling type with inferior thinking.
When I got to know him in 1907 this original type was already neurotically blurred.
In observing a neurotic, one does not know at first whether one is observing the conscious or the unconscious character.
Freud, then as later, presented the picture of an extraverted thinker
His overvaluation of thinking coupled with his irresponsible manner of
observation aroused my doubts as to his type.
The subjective overvaluation of his thinking is illustrated by his dictum: "This must be correct because I have thought it."
His irresponsible manner of observation is demonstrated by the fact, for instance, that not one of his cases of "traumatic" hysteria was verified.
He relied on the veracity of his hysterical patients.
When I analysed Freud a bit further in 1909 on account of a neurotic symptom, I discovered traces which led me to infer a marked injury to his feeling life.
Experience shows that at such moments a feeling type switches over to thinking as the counterfunction, together with the compensatory overvaluation.
The original auxiliary function -in this case intuition-is replaced by a somewhat deficient "function du reel ."
This transformation has been described by the French as "simulation dans la charactere."
Freud, when one got to know him better, was distinguished by a markedly differentiated feeling function.
His "sense of values" showed itself in his love of precious stones, jade, malachite, etc.
He also had considerable intuition.
Yet the superficial picture he presented to the world was that of an extraverted thinker and empiricist who derived his philosophy of life from the man in the street, which is supposed to be modern.
This mutability of the psychological type makes the question of its relation to the somatic type an extremely complicated problem.
And when we take the results of personality development into account, the crude features of introversion and extraversion are also reversed.
The case of a man of 36 with a cardiac neurosis may serve as an example.
He was an obviously extraverted type, and his wife was introverted to a pathological degree.
They got a divorce.
He then married an extremely extraverted woman, lost his cardiac neurosis, and became a typical introvert with the feeling that this was his true nature.
He was a successful businessman who from humble beginnings had
worked his way to the top.
His originally introverted disposition was kept under by his hard struggle and energetic will, but had to be married in the form of an introverted wife and paid for with a cardiac neurosis.
I hope these few hints will show you why I regard the identity of somatic and psychological types, if not exactly as a question of incommensurables, then at least as a problem that at present remains completely unsolved.
With collegial regards,
C.G. Jung ~Carl Jung, Letters Vol. II, Pages 346-348