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Biological naturalism is a theory about, among other things, the relationship between consciousness and body (i.e. brain), and hence an approach to the mind-body problem. It was first proposed by the philosopher John Searle in 1980 and is defined by two main theses: 1) all mental phenomena from pains, tickles, and itches to the most abstruse thoughts are caused by lower-level neurobiological processes in the brain; and 2) mental phenomena are higher-level features of the brain. This entails that the brain has the right causal powers to produce intentionality. However, Searle's biological naturalism does not entail that brains and ''only'' brains can cause consciousness. Searle is careful to point out that while it appears to be the case that certain brain functions are sufficient for producing conscious states, our current state of neurobiological knowledge prevents us from concluding that they are necessary for producing consciousness. In his own words:
==Overview== Searle denies Cartesian dualism, the idea that the mind is a separate kind of substance to the body, as this contradicts our entire understanding of physics, and unlike Descartes, he does not bring God into the problem. Indeed, Searle denies any kind of dualism, the traditional alternative to monism, claiming the distinction is a mistake. He rejects the idea that because the mind is not objectively viewable, it does not fall under the rubric of physics. Searle believes that consciousness "is a real part of the real world and it cannot be eliminated in favor of, or reduced to, something else" 〔 ''John R. Searle: Thinking about the Real World'' by Dirk Franken, Attila Karakus, and Jan G. Michel ()〕 whether that something else is a neurological state of the brain or a software program. He contends, for example, that the software known as Deep Blue ''knows'' nothing about chess. He also believes that consciousness is both a cause of events in the body and a response to events in the body. On the other hand, Searle doesn't treat consciousness as a ghost in the machine. He treats it, rather, as a state of the brain. The causal interaction of mind and brain can be described thus in naturalistic terms: Events at the micro-level (perhaps at that of individual neurons) cause consciousness. Changes at the macro-level (the whole brain) constitute consciousness. Micro-changes cause and then are impacted by holistic changes, in much the same way that individual football players cause a team (as a whole) to win games, causing the individuals to gain confidence from the knowledge that they are part of a winning team. He articulates this distinction by pointing out that the common philosophical term 'reducible' is ambiguous. Searle contends that consciousness is "causally reducible" to brain processes without being "ontologically reducible." He hopes that making this distinction will allow him to escape the traditional dilemma between reductive materialism and substance dualism; he affirms the essentially physical nature of the universe by asserting that consciousness is completely caused by and realized in the brain, but also doesn't deny what he takes to be the obvious facts that humans really are conscious, and that conscious states have an essentially first-person nature. It can be tempting to see the theory as a kind of property dualism, since, in Searle's view, a person's mental properties are categorically different from his or her micro-physical properties. The latter have "third-person ontology" whereas the former have "first-person ontology." Micro-structure is accessible objectively by any number of people, as when several brain surgeons inspect a patient's cerebral hemispheres. But pain or desire or belief are accessible subjectively by the person who has the pain or desire or belief, and no one else has that mode of access. However, Searle holds mental properties to be a species of physical property—ones with first-person ontology. So this sets his view apart from a dualism of physical and non-physical properties. His mental properties are putatively physical. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Biological naturalism」の詳細全文を読む スポンサード リンク
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