Wolfgang Pauli: Unlike your own ideas those of Speiser are, I must confess, often difficult to understand.

Dear Professor Jung: February 2, 1951

Many thanks for sending me the edited version of your manuscript.

I paid particular attention to the new version of chap. IV and found that it reflects faithfully the state of affairs with the problems at the moment and, from the standpoint of modern physics, is now unassailable.

I was a little taken aback by the relatively large amount of space devoted to your discussion with A. Speiser.

Unlike your own ideas those of Speiser are, I must confess, often difficult to understand.

Some of them also seem out of date; in particular, remarks such as the “initial state, which is not determined by the law alone” and then “is carried through time completely according to the law” represent the point of view of classical physics and not modern nuclear physics.

In the latter, every observation is basically an intervention that interrupts the causal connection.

And furthermore, is it not a regression into the extreme “Nominalism” (in the sense of the medieval polemic between “Nominalism” and “Realism”) to dismiss any concept as “Nothing”.?

But this, of course, is just a small detail in your new chapter, which I would like to say, once again meets with my wholehearted approval.

I look forward to your lecture on Saturday and remain until then with best wishes,

Yours sincerely,

W PAULI ~Wolfgang Pauli, Atom and Archetype, Page 71.