Editing Hidden-variable theory (section)

=== "God does not play dice" ===
In June 1926, [[Max Born]] published a paper,<ref>{{Cite journal |last=Born |first=Max |date=1926 |title=Zur Quantenmechanik der Stoßvorgänge |url=http://link.springer.com/10.1007/BF01397477 |journal=Zeitschrift für Physik |language=de |volume=37 |issue=12 |pages=863–867 |doi=10.1007/BF01397477 |bibcode=1926ZPhy...37..863B |s2cid=119896026 |issn=1434-6001}}</ref> in which he was the first to clearly enunciate the probabilistic interpretation of the quantum [[wavefunction|wave function]], which had been introduced by [[Erwin Schrödinger]] earlier in the year. Born concluded the paper as follows:{{blockquote|Here the whole problem of determinism comes up. From the standpoint of our quantum mechanics there is no quantity which in any individual case causally fixes the consequence of the collision; but also experimentally we have so far no reason to believe that there are some inner properties of the atom which conditions a definite outcome for the collision. Ought we to hope later to discover such properties ... and determine them in individual cases? Or ought we to believe that the agreement of theory and experiment—as to the impossibility of prescribing conditions for a causal evolution—is a pre-established harmony founded on the nonexistence of such conditions? I myself am inclined to give up determinism in the world of atoms. But that is a philosophical question for which physical arguments alone are not decisive.}}Born's interpretation of the wave function was criticized by Schrödinger, who had previously attempted to interpret it in real physical terms, but [[Albert Einstein]]'s response became one of the earliest and most famous assertions that quantum mechanics is incomplete:{{blockquote|Quantum mechanics is very worthy of respect. But an inner voice tells me this is not the genuine article after all. The theory delivers much but it hardly brings us closer to the Old One's secret. In any event, I am convinced that ''He'' is not playing dice.<ref name="Einstein letter, 4 Dec 1926">[https://einsteinpapers.press.princeton.edu/vol15-trans/437 The Collected Papers of Albert Einstein, Volume 15: The Berlin Years: Writings & Correspondence, June 1925-May 1927 (English Translation Supplement), p. 403]</ref><ref>{{cite book|title=The Born–Einstein letters: correspondence between Albert Einstein and Max and Hedwig Born from 1916–1955, with commentaries by Max Born|year=1971|publisher=Macmillan|page=91}}</ref>}}[[Niels Bohr]] reportedly replied to Einstein's later expression of this sentiment by advising him to "stop telling God what to do."<ref>This is a common paraphrasing.  Bohr recollected his reply to Einstein at the 1927 [[Solvay Congress]] in his essay "Discussion with Einstein on Epistemological Problems in Atomic Physics", in ''Albert Einstein, Philosopher–Scientist'', ed. Paul Arthur Shilpp, Harper, 1949, p. 211: "...in spite of all divergencies of approach and opinion, a most humorous spirit animated the discussions.  On his side, Einstein mockingly asked us whether we could really believe that the providential authorities took recourse to dice-playing ("''ob der liebe Gott würfelt''"), to which I replied by pointing at the great caution, already called for by ancient thinkers, in ascribing attributes to Providence in everyday language."  Werner Heisenberg, who also attended the congress, recalled the exchange in ''Encounters with Einstein'', Princeton University Press, 1983, p. 117,: "But he [Einstein] still stood by his watchword, which he clothed in the words: 'God does not play at dice.'  To which Bohr could only answer: 'But still, it cannot be for us to tell God, how he is to run the world.'"</ref>