On EPR Paradox In The Perspective Of Philosophy Of Science

The EPR argument in 1935 elicited the contradiction between local realism and the completeness of quantum mechanics. Schrodinger considered this contradiction as "EPR paradox" which was later accepted by David Bohm and John Bell. Since Bell Inequality was proposed, there have been many corresponding experiments and tests, which were regarded as "crucial experiments" to the decision between two sides of the contradiction. Many physicists expected that a clear-cut decision could be made between local realism and the completeness of quantum mechanics in virtue of these experimental results, that is to say, the experimental results could decisively support one while reject the other. However, the attempts to make such "last crucial" experiments still failed with so many years' efforts, Nevertheless, some problems like non-locality and quantum entanglement were produced in the process of pursuing for the critical experiments, and these problems were the key of developing quantum technology. The paper of EPR with just 4 pages, like a key to a mysterious treasure, had been leading people to find out innumerable wisdom treasures.Generally speaking, the studies to the EPR paradox in the last seventies years mainly have two approaches:one is philosophical and the other is scientific. In more than ten years after Niels Bohr published the same-name paper to respond the EPR paradox in 1935, the argument for the EPR paradox gradually ascended to the philosophical level from the scientific level. That is partly because of the restrictions of physical experimental technology and the change of social environment, and on the other hand, the attention paid to some philosophical thesis such as causality and objective reality by Albert Einstein, and particularly Bohr's Complementary Principle with philosophical meaning gave EPR paradox much more philosophical impression. What followed from this route was the philosophical research approach which had continued to this day and focused on the important effects made on causality and reality by quantum mechanics. The other approach was scientific, and after Bohm simplified the thought experiment in EPR original paper in 1951, there was a possibility for employing true experiment to test EPR paradox. With the development of Bell Inequality and experimental technology, the identity of the scientific thesis about EPR paradox recovered. EPR paradox had become a kind of "experimental metaphysics" under the influence of these two approaches.Many accomplishments have been made about the study of EPR paradox both metaphysically and scientifically for such a long time. Therefore, if we keep on studying EPR paradox either metaphysically or scientifically, it will be probably just a simple repetition of others'works, which may be not only cost too much time but also of little significance. Nonetheless, with careful investigation, we found that there will be many things to do about EPR paradox, and we can have another approach to choose, namely, the approach of philosophy of science. This kind of approach should be the integration of the previous two approaches, and it is more positive than the metaphysical approach, and more philosophical than the pure scientific approach. As a result, it will indicate the role of methodology played in scientific development more apparently, and will be more according with the spirit of "experimental metaphysics". This thesis will be concerned with the following problems.The first problem is about scientific rationality and scientific belief. The rationality of scientists is based on experimental data. Because they respected experiments and data, they discovered energy quanta and light quantum. The belief of scientists is based on their scientific faith, for example, Einstein believes the strict causality of classical mechanics, so his belief is "Spinoza's God", while Bohr's belief is not enslaved to any given systems and welcoming new problems and new viewpoints in any time, so there is Copenhagen Interpretation.The second problem is about critical experiment. Among various viewpoints about crucial experiments in philosophy of science, we are inclined to support the following point of view:crucial experiment has relative crucial effect. Moreover, we think that the relativity of crucial effect lies in the relative reliability and historicality of background knowledge as foundation. The reliable background knowledge in some historic time will probably expose its hidden defects with the development of our knowledge. The background knowledge will never obtain absolute reliability, even though it is endlessly revised in the historical course. Consequently, the crucial experiments based on such background knowledge are not absolute reliable as well, and for that reason Bell typed experiments which have been taken as crucial experiments and new EPR paradox typed experiments are not referred to as the ultimate judge for EPR paradox.The third problem is about paradox. Literally, paradox means something contrary to the usual well-accepted point of view. "Paradox can be defined as unaccepted conclusion reliably deduced from the well-accepted premise." The root of paradox consists in that the seeming reasonable premise or background is flawed, so if we want to resolve the EPR paradox, we must find out something wrong with the premise. However, because of the relative reliability of background knowledge, the resolution of paradox is also relative." Local non-separability" proposed by Howard is a successful case of trying to solute paradox from background knowledge.The fourth problem is about the role played by thought experiments and scientific paradox in scientific development. Thought experiments have played an important role in history of physics, especially in the contemporary history of physics. Many great thoughts were discovered through thought experiments, which are important way of promoting the discovery of scientific theories and can be viewed as "the shovel of thoughts". Scientific paradox can be divided into ones revealed by specific theories or actual experiment and ones derived from thought experiments. It aims to examine scientific theories and reveal the deep paradoxes concealed in theories which are usually the contradiction in meta-theory level, so we look on scientific paradox as " the microscope of thought". With these two powerful instruments, we can fearlessly proceed and discover problems at any time in order to revise the direction in the course of science.The fifth problem is about the individuality of microscopic particles. The problem of individuality which evolved from "how macroscopic objects have individuality" to "whether microscopic particles have individuality or not", became more complicated after the naissance of quantum mechanics. The indiscernibility of microscopic particles (identical particles) and non-separability of quantum systems (the lost of self-identity) make some scientists and philosophers conclude that microscopic particles didn't have individuality. But we have different points of view. First of all, "indiscernibility "which is a concept epistemologically is not identical with "indistinguishability" which is a concept ontologically, so "indiscernible" microscopic particles might be still "distinguishable". "Distinguishablity" is a sufficient condition of individuality, and we will argue that distinguishablity has individuality (at least partial individuality) by means of "cardinal distinguishablity". Then we extend "the relative separable holism" to "the relative separable individuality", and point out that non-separablity of quantum systems is not identical with the absolute non-separable holism, because microscopic particles still keep their self-identity. That is to say, individuality doesn't totally lost and just weaken to some extent so that it indicates a kind of individuality different from macroscopic objects. Therefore, it could explain that quantum systems have weak "local realism" in Einstein's sense, in which sense EPR paradox can be resolved.The last problem is about the coordination between special relativity and quantum mechanics. The contradiction between local realism and quantum mechanics in deep sense means the contradiction between special relativity and quantum mechanics which are contemporarily both the greatest research programs, because local realism is one of the core hypotheses of special relativity. Abandoning either one of them is unacceptable even emotionally, so people have done much efforts of coordinating them to eliminate EPR paradox. The'local non-separablity" proposed by Howard is a good example, which motivates us to coordinate them from the perspective of quantum's " weak individuality". On one hand, quantum entanglement and long-range correlation have become real facts, and on the other hand, "locality" of quantum particles doesn't lost, and interaction is still local and non=act-at-a-distance. The former is asserted by quantum physicists, while the latter is expected by Einstein. Therefore, coordinating quantum mechanics and relativity to make them "peacefully coexist" is of great possibility.