P.A.M. Dirac, ‘The Development Of Quantum Mechanics’, Conferenza Tenuta il 14 Aprile 1972, Roma, Accademia Nazionale dei Lincei, 1974, 11 pages.

“This statistical interpretation is now universally accepted as the best possible interpretation for quantum mechanics, even
though many people are unhappy with it. People had got used to the determinism of the last century, where the present determines the future completely, and they now have to get used
to a different situation in which the present only gives one information of a statistical nature about the future. A good many people find this unpleasant; Einstein has always objected to it. The way he expressed it was: ‘The good God does not play with dice’. Schroedinger also did not like the statistical interpretation and tried for many years to find an interpretation
involving determinism for his waves. But it was not successful as a general method. I must say that I also do not like indeterminism. I have to accept it because it is certainly the best that we can do with our present knowledge. One can always hope that there will be future developments which will lead to a drastically different theory from the present quantum mechanics and for which there may be a partial return of determinism. However, so long as one keeps to the present formalism, one has to have this indeterminism.”