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Scientific realism Scientific realism is, at the most general level, the view that the world described by science (perhaps ideal science) is the real world, as it is, independent of what we might take it to be. Within philosophy of science, it is often framed as an answer to the question "how is the success of science to be explained?" The debate over what the success of science involves centers primarily on the status of entities that are not directly observable discussed by scientific theories. Generally, those who are scientific realists state that one can make reliable claims about these entities (viz., that they have the same ontological status) as directly observable entities, as opposed to instrumentalism. Realism and locality in physics Realism in the sense used by physicists does not equate to realism in metaphysics.[12] The latter is the claim that the world is mind-independent: that even if the results of a measurement do not pre-exist the act of measurement, that does not require that they are the creation of the observer. Furthermore, a mind-independent property does not have to be the value of some physical variable such as position or momentum. A property can be dispositional (or potential), i.e. it can be a tendency: in the way that glass objects tend to break, or are disposed to break, even if they do not actually break. Likewise, the mind-independent properties of quantum systems could consist of a tendency to respond to particular measurements with particular values with ascertainable probability.[13] Such an ontology would be metaphysically realistic, without being realistic in the physicist's sense of "local realism" (which would require that a single value be produced with certainty). A closely related term is counterfactual definiteness (CFD), used to refer to the claim that one can meaningfully speak of the definiteness of results of measurements that have not been performed (i.e. the ability to assume the existence of objects, and properties of objects, even when they have not been measured). Local realism is a significant feature of classical mechanics, of general relativity, and of electrodynamics; but quantum mechanics has shown that quantum entanglement is possible. This was rejected by Einstein, who proposed the EPR paradox, but it was subsequently quantified by Bell's inequalities.[14] If Bell's inequalities are violated, either local realism or counterfactual definiteness must be incorrect; but some physicists dispute that experiments have demonstrated Bell's violations, on the grounds that the sub-class of inhomogeneous Bell inequalities has not been tested or due to experimental limitations in the tests. Different interpretations of quantum mechanics violate different parts of local realism and/or counterfactual definiteness. Role of the observer in quantum mechanics The quantum mind–body problem refers to the philosophical discussions of the mind–body problem in the context of quantum mechanics. Since quantum mechanics involves quantum superpositions, which are not perceived by observers, some interpretations of quantum mechanics place conscious observers in a special position. The founders of quantum mechanics debated the role of the observer, and of them, Wolfgang Pauli and Werner Heisenberg believed that it was the observer that produced collapse. This point of view, which was never fully endorsed by Niels Bohr, was denounced as mystical and anti-scientific by Albert Einstein. Pauli accepted the term, and described quantum mechanics as lucid mysticism.[15] Heisenberg and Bohr always described quantum mechanics in logical positivist terms. Bohr also took an active interest in the philosophical implications of quantum theories such as his complementarity, for example.[16] He believed quantum theory offers a complete description of nature, albeit one that is simply ill suited for everyday experiences – which are better described by classical mechanics and probability. Bohr never specified a demarcation line above which objects cease to be quantum and become classical. He believed that it was not a question of physics, but one of philosophy. Eugene Wigner reformulated the "Schrödinger's cat" thought experiment as "Wigner's friend" and proposed that the consciousness of an observer is the demarcation line which precipitates collapse of the wave function, independent of any realist interpretation. Commonly known as "consciousness causes collapse", this interpretation of quantum mechanics states that observation by a conscious observer is what makes the wave function collapse. Multiverse The multiverse is the hypothetical set of multiple possible universes (including the historical universe we consistently experience) that together comprise everything that exists: the entirety of space, time, matter, and energy as well as the physical laws and constants that describe them. The term was coined in 1895 by the American philosopher and psychologist William James.[17] In the many-worlds interpretation (MWI), one of the mainstream interpretations of quantum mechanics, there are an infinite number of universes and every possible quantum outcome occurs in at least one universe. The structure of the multiverse, the nature of each universe within it and the relationship between the various constituent universes, depend on the specific multiverse hypothesis considered. Multiverses have been hypothesized in cosmology, physics, astronomy, religion, philosophy, transpersonal psychology and fiction, particularly in science fiction and fantasy. In these contexts, parallel universes are also called "alternative universes", "quantum universes", "interpenetrating dimensions", "parallel dimensions", "parallel worlds", "alternative realities", "alternative timelines", and "dimensional planes," among others. Scientific theories of everything A theory of everything (TOE) is a putative theory of theoretical physics that fully explains and links together all known physical phenomena, and predicts the outcome of any experiment that could be carried out in principle. The theory of everything is also called the final theory.[18] Many candidate theories of everything have been proposed by theoretical physicists during the twentieth century, but none have been confirmed experimentally. The primary problem in producing a TOE is that general relativity and quantum mechanics are hard to unify. This is one of the unsolved problems in physics. Initially, the term "theory of everything" was used with an ironic connotation to refer to various overgeneralized theories. For example, a great-grandfather of Ijon Tichy, a character from a cycle of Stanisław Lem's science fiction stories of the 1960s, was known to work on the "General Theory of Everything". Physicist John Ellis[19] claims to have introduced the term into the technical literature in an article in Nature in 1986.[20] Over time, the term stuck in popularizations of quantum physics to describe a theory that would unify or explain through a single model the theories of all fundamental interactions and of all particles of nature: general relativity for gravitation, and the standard model of elementary particle physics – which includes quantum mechanics – for electromagnetism, the two nuclear interactions, and the known elementary particles. Current candidates for a theory of everything include string theory, M theory, and loop quantum gravity. Technology Virtual reality and cyberspace Virtual reality (VR) is a term that applies to computer-simulated environments that can simulate physical presence in places in the real world, as well as in imaginary worlds. Reality-Virtuality Continuum. The Virtuality Continuum is a continuous scale ranging between the completely virtual, a Virtuality, and the completely real: Reality. The reality-virtuality continuum therefore encompasses all possible variations and compositions of real and virtual objects. It has been described as a concept in new media and computer science, but in fact it could be considered a matter of anthropology. The concept was first introduced by Paul Milgram.[21] The area between the two extremes, where both the real and the virtual are mixed, is the so-called Mixed reality. This in turn is said to consist of both Augmented Reality, where the virtual augments the real, and Augmented virtuality, where the real augments the virtual. Cyberspace, the world's computer systems considered as an interconnected whole, can be thought of as a virtual reality; for instance, it is portrayed as such in the cyberpunk fiction of William Gibson and others. Second life and MMORPGs such as World of Warcraft are examples of artificial environments or virtual worlds (falling some way short of full virtual reality) in cyberspace. "RL" in internet culture On the Internet, "real life" refers to life in the real world. It generally references life or consensus reality, in contrast to an environment seen as fiction or fantasy, such as virtual reality, lifelike experience, dreams, novels, or movies. Online, the acronym "IRL" stands for "in real life", with the meaning "not on the Internet".[22] Sociologists engaged in the study of the Internet have determined that someday, a distinction between online and real-life worlds may seem "quaint", noting that certain types of online activity, such as sexual intrigues, have already made a full transition to complete legitimacy and "reality".[23] The abbreviation "RL" stands for "real life". For example, one can speak of "meeting in RL" someone whom one has met in a chat or on an Internet forum. It may also be used to express an inability to use the Internet for a time due to "RL problems". |
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