Einstein wrote in a letter to Max Born that he feels that QM is not the true Jacob, quote: "Quantum mechanics demands serious attention. But an inner voice tells me that this is not the true Jacob. The theory accomplishes a lot, but it does not bring us closer to the secrets of the Old One. In any case, I am convinced that He does not play dice." So who is the Jacob he is referring to, is it the biblical Jacob who tricked his father into blessing him instead of his brother Esau? But then the saying should be: "But an inner voice tells me that this is not the true Esau" because the Father thought that Jacob is Esau and not the other way around. Hope someone can tell, Thanks.