D O C U M E N T S 4 , 5 M A Y 1 9 2 0 1 5 1
4. To Niels Bohr[1]
[Berlin,] 2 May 1920
Dear Mr. Bohr,
The splendid gift from the Land of Neutrality, where milk and honey still trickle,
gives me a welcome opportunity to write
you.[2]
My cordial thanks to you. Not of-
ten in life has the mere presence of a person given me such pleasure as
you.[3]
I un-
derstand now why Ehrenfest loves you so
much.[4]
I am studying your great papers
now and—when I happen to get stuck somewhere—have the pleasure of seeing
your kindly, boyish face before me, smiling and explaining. I have learned much
from you, especially how you feel about scientific
matters.[5]
The way in which you derive individual quantum states successively with the aid
of quantum states (“by means of the Riemann surface”) remains somewhat opaque
to me. For it seems to me that the reversal of the process that yields state
from state , generates from state state , which clearly is not
supposed to be a quantum state. Somewhere one passes through a discontinuous
change in integration time, if I have understood you
correctly.[6]
I am very much looking forward to our discussions in
Copenhagen.[7]
In the
meantime, wishing you a happy time and blessed efforts, yours,
A. Einstein.
5. To Hans Wittig
Berlin, 3 May 1920
Dear Sir,
I am very willing to check your work. Provided I find it clear and to the point, I
shall be glad to accept your
dedication,[1]
although I would like to note from the
start that I do not consider myself competent in philosophical matters. The
pompous vocabulary and revolutionary gestures in your letter make me suspicious;
Truth tends to appear modestly and in simple dress. As concerns your intention to
attempt a doctorate, I don’t really know, since I personally am not a member of any
faculty[2]
and am just better acquainted with the Swiss situation. But this much I
do know, that in these affairs officialism blossoms and thrives just as it did under
the old
regime.[3]
But that is tomorrow’s worry [cura posterior]; the main thing is,
of course, the work itself. If it is interesting, with God’s help a full professor in
I2 h =
I1 2h = I1 h = I
h
2
-=--