Quantum Theory : Albert Einstein ( 2 )

Below are some further quotes from Albert Einstein on Quantum Theory. Please see main Albert Einstein Quantum Theory page for more details.

You believe in the God who plays dice, and I in complete law and order in a world which objectively exists, and which I, in a wildly speculative way, am trying to capture. I hope that someone will discover a more realistic way, or rather a more tangible basis than it has been my lot to find. Even the great initial success of the Quantum Theory does not make me believe in the fundamental dice-game, although I am well aware that our younger colleagues interpret this as a consequence of senility. No doubt the day will come when we will see whose instinctive attitude was the correct one. (Albert Einstein to Max Born, Sept 1944, 'The Born-Einstein Letters')
For the time being we have to admit that we do not possess any general theoretical basis for physics which can be regarded as its logical foundation. The field theory, so far, has failed in the molecular sphere. It is agreed on all hands that the only principle which could serve as a basis of quantum theory would be one that constituted a translation of the field theory into the scheme of quantum statistics. Whether this will actually come about in a satisfactory manner, nobody can venture to say. Some physicists, among them myself, cannot believe that we must abandon, actually and forever, the idea of direct representation of physical reality in space and time; or that we must accept the view that events in nature are analogous to a game of chance . Probably never before has a theory been evolved which has given a key to the interpretation and calculation of such a heterogeneous group of phenomena of experience as has quantum theory. In spite of this, however, I believe that the theory is apt to beguile us into error in our search for a uniform basis for physics, because, in my belief, it is an incomplete representation of real things, although it is the only one which can be built out of the fundamental concepts of force and material points (quantum corrections to classical mechanics). The incompleteness of the representation leads necessarily to the statistical nature (incompleteness) of the laws. (Albert Einstein, on Quantum Physics, 1954)
The next step was taken by de Broglie. He asked himself how the discrete states could be understood by the aid of current concepts, and hit on a parallel with stationary (standing) waves, as for instance in the case of proper frequencies of organ pipes and strings in acoustics. (Albert Einstein, on Quantum Theory, 1954)
Experiments on interference made with particle rays have given brilliant proof that the wave character of the phenomena of motion as assumed by the theory does, really, correspond to the facts. (Albert Einstein, on Quantum Theory, 1954)
On the basis of quantum theory there was obtained a surprisingly good representation of an immense variety of facts which otherwise appeared entirely incomprehensible. But on one point, curiously enough, there was failure: it proved impossible to associate with these Schrodinger waves definite motions of the mass points - and that, after all, had been the original purpose of the whole construction. The difficulty appeared insurmountable until it was overcome by Born in a way as simple as it was unexpected. The de Broglie-Schrodinger wave fields were not to be interpreted as a mathematical description of how an event actually takes place in time and space, though, of course, they have reference to such an event. Rather they are a mathematical description of what we can actually know about the system. They serve only to make statistical statements and predictions of the results of all measurements which we can carry out upon the system. (Quantum Mechanics, Albert Einstein, 1940)
It seems to be clear, therefore, that Born's statistical interpretation of quantum theory is the only possible one. The wave function does not in any way describe a state which could be that of a single system; it relates rather to many systems, to an 'ensemble of systems' in the sense of statistical mechanics. (Albert Einstein, on Quantum Theory, 1936)
All attempts to represent the particle and wave features displayed in the phenomena of light and matter, by direct recourse to a space time model, have so far ended in failure. And Heisenberg has convincingly shown, from an empirical point of view, that any decision as to a rigorously deterministic structure of nature is definitely ruled out, because of the atomistic structure of our experimental apparatus. (Quantum Physics, Albert Einstein, 1954)
All these fifty years of conscious brooding have brought me no nearer to the answer to the question, 'What are light quanta?' Nowadays every Tom, Dick and Harry thinks he knows it, but he is mistaken. (Albert Einstein, 'The Born-Einstein Letters' Max Born, translated by Irene Born, Macmillan 1971)
I still do not believe that the statistical method of the Quantum Theory is the last word, but for the time being I am alone in my opinion. (Albert Einstein, 1936, 'The Born-Einstein Letters' Max Born, translated by Irene Born, Macmillan 1971)
Quantum mechanics is certainly imposing. But an inner voice tells me that it is not yet the real thing. Quantum theory says a lot, but does not really bring us any closer to the secret of the Old One. I, at any rate, am convinced that He (God) does not throw dice. (Albert Einstein, On Quantum Physics, Letter to Max Born, December 12, 1926)
Einstein thinks he has a continuous field theory that avoids 'spooky action at a distance', but the calculation difficulties are very great. He is quite convinced that some day a theory that does not depend on probabilities will be found. (Albert Einstein to Max Born, 1947, 'The Born-Einstein Letters' Max Born, translated by Irene Born, Macmillan 1971)
I am well aware that no causality exists in relation to the observable; I consider this realisation to be conclusive. But in my opinion one should not conclude from this that the theory, too, has to be based on fundamental laws of statistics. It is, after all, possible that the (molecular) structure of the means of observation involves the statistical character of the observable, but that it is expedient in the end to keep the basis of the theory free from statistical concepts. (Albert Einstein to Max Born, 1948, 'The Born-Einstein Letters' Max Born, translated by Irene Born, Macmillan 1971)
I think that matter must have a separate reality independent of the measurements. That is an electron has spin, location and so forth even when it is not being measured. I like to think that the moon is there even if I am not looking at it. (Albert Einstein)
All my attempts to adapt the theoretical foundation of physics to this new type of knowledge (Quantum Theory) failed completely. It was as if the ground had been pulled out from under one, with no firm foundation to be seen anywhere, upon which one could have built. (P. A Schlipp, Albert Einstein: Philosopher – Scientist, On Quantum Theory, 1949)
The quanta really are a hopeless mess. (Albert Einstein, On doing Quantum Theory calculations with Pauli, 'The Born-Einstein Letters' Max Born, translated by Irene Born, Macmillan 1971)