D O C . 1 7 0 O N O V E R D E T E R M I N A T I O N 2 7 5
attempts at giving tangible form to my pet idea of interpreting quantum structure through an overde-
termination with differential equations refuse to succeed” (“Ich brüte in meiner freien Zeit immer
über das Quantenproblem vom Standpunkt der Relativität. Ich glaube nicht, dass die Theorie das Kon-
tinuum wird entbehren können. Es will mir aber nicht gelingen, meiner Lieblingsidee, die Quanten-
struktur aus einer Überbestimmung durch Differentialgleichungen zu verstehen, greifbare Gestalt zu
geben” Einstein to Max Born, 3 March 1920 [Vol. 9, Doc. 337]). By April 1920, Einstein apparently
had given up on this approach for the time being: “Overdetermination does not work” (“Eine Über-
bestimmung gelingt nicht”; Einstein to Paul Ehrenfest, 7 April 1920 [Vol. 9, Doc. 371]).
The footnote is missing in the manuscript.
After “Range,” the manuscript adds “ den Energietensor des elektromagnetischen Feldes.”
For the case where the energy-momentum tensor is trace-free, as is the case for the electromagnetic
field, the field equations equating the Einstein tensor or the Ricci tensor to the energy-
momentum tensor are equivalent, since the trace-freeness of energy-momentum implies that the
Ricci scalar R must vanish.
In Einstein and Grommer 1923a (Vol. 13, Doc. 12), Einstein had first demanded that field the-
ory should improve on the Einstein-Maxwell equations by generalizing the field equations in such a
way that they would allow for static spherically symmetric solutions that could be interpreted as ele-
mentary electric charges. For details, see Einstein and Grommer 1923a (Vol. 13, Doc. 12), note 9; the
criterion also occurs in Einstein 1923n (Doc. 52). Until now, Einstein had applied the criterion in the
context of the Kaluza-Klein theory and in the context of affine field theory; in the present, program-
matic, document, it appears as one of three necessary but even jointly not sufficient conditions for the
In the manuscript, the passage between “folgende Bedingungen eingeschränkt werden” (in the
line before 1. above) and “mitbestimmt wird” exists also in a slightly different version that was later
Apparently, Einstein is citing from the fourth edition (see Weyl 1921, §32).
The Nachtrag (supplement) is missing in the manuscript.
For further historical discussion of this document, see Pais 1982, pp. 464–465; Vizgin 1994,
pp.197–204; Goenner 2004, sec. 4.3.4; and Sauer 2014a, pp. 293–294.