Epiphenomenalism is a position on the mind–body problem which holds that physical and biochemical events within the human body (sense organs, neural impulses, and muscle contractions, for example) are causal with respect to mental events (thought, consciousness, and cognition). According to this view, subjective mental events are completely dependent for their existence on corresponding physical and biochemical events within the human body yet themselves have no causal efficacy on physical events. The appearance that subjective mental states (such as intentions) influence physical events is merely an illusion. For instance, fear seems to make the heart beat faster, but according to epiphenomenalism the biochemical secretions of the brain and nervous system (such as adrenaline)—not the experience of fear—is what raises the heartbeat.Because mental events are a kind of overflow that cannot cause anything physical, yet have non-physical properties, epiphenomenalism is viewed as a form of property dualism.
During the seventeenth century, René Descartes argued that animals are subject to mechanical laws of nature. He defended the idea of automatic behavior, or the performance of actions without conscious thought. Descartes questioned how the immaterial mind and the material body can interact causally.His interactionist model (1649) held that the body relates to the mind through the pineal gland. La Mettrie, Leibniz, and Spinoza all in their own way began this way of thinking. The idea that even if the animal were conscious nothing would be added to the production of behavior, even in animals of the human type, was first voiced by La Mettrie (1745), and then by Cabanis (1802), and was further explicated by Hodgson (1870) and Huxley (1874).
Thomas Henry Huxley agreed with Descartes that behavior is determined solely by physical mechanisms, but he also believed that humans enjoy an intelligent life. In 1874, Huxley argued, in the Presidential Address to the British Association for the Advancement of Science, that animals are conscious automata. Huxley proposed that psychical changes are collateral products of physical changes. He termed the stream of consciousness an "epiphenomenon;" like the bell of a clock that has no role in keeping the time, consciousness has no role in determining behavior.
Huxley defended automatism by testing reflex actions, originally supported by Descartes. Huxley hypothesized that frogs that undergo lobotomy would swim when thrown into water, despite being unable to initiate actions. He argued that the ability to swim was solely dependent on the molecular change in the brain, concluding that consciousness is not necessary for reflex actions. According to epiphenomenalism, animals experience pain only as a result of neurophysiology.
In 1870, Huxley conducted a case study on a French soldier who had sustained a shot in the Franco-Prussian War that fractured his left parietal bone. Every few weeks the soldier would enter a trance-like state, smoking, dressing himself, and aiming his cane like a rifle all while being insensitive to pins, electric shocks, odorous substances, vinegar, noise, and certain light conditions. Huxley used this study to show that consciousness was not necessary to execute these purposeful actions, justifying the assumption that humans are insensible machines. Huxley's mechanistic attitude towards the body convinced him that the brain alone causes behavior.
In the early 1900s scientific behaviorists such as Ivan Pavlov, John B. Watson, and B. F. Skinner began the attempt to uncover laws describing the relationship between stimuli and responses, without reference to inner mental phenomena. Instead of adopting a form of eliminativism or mental fictionalism, positions that deny that inner mental phenomena exist, a behaviorist was able to adopt epiphenomenalism in order to allow for the existence of mind. George Santayana (1905) believed that all motion has merely physical causes. Because consciousness is accessory to life and not essential to it, natural selection is responsible for ingraining tendencies to avoid certain contingencies without any conscious achievement involved.By the 1960s, scientific behaviourism met substantial difficulties and eventually gave way to the cognitive revolution. Participants in that revolution, such as Jerry Fodor, reject epiphenomenalism and insist upon the efficacy of the mind. Fodor even speaks of "epiphobia"—fear that one is becoming an epiphenomenalist.
However, since the cognitive revolution, there have been several who have argued for a version of epiphenomenalism. In 1970, Keith Campbell proposed his "new epiphenomenalism", which states that the body produces a spiritual mind that does not act on the body. How the brain causes a spiritual mind, according to Campbell, is destined to remain beyond our understanding forever (see New Mysterianism).In 2001, David Chalmers and Frank Jackson argued that claims about conscious states should be deduced a priori from claims about physical states alone. They offered that epiphenomenalism bridges, but does not close, the explanatory gap between the physical and the phenomenal realms. These more recent versions maintain that only the subjective, qualitative aspects of mental states are epiphenomenal. Imagine both Pierre and a robot eating a cupcake. Unlike the robot, Pierre is conscious of eating the cupcake while the behavior is under way. This subjective experience is often called a quale (plural qualia), and it describes the private "raw feel" or the subjective "what-it-is-like" that is the inner accompaniment of many mental states. Thus, while Pierre and the robot are both doing the same thing, only Pierre has the inner conscious experience.
Frank Jackson (1982), for example, once espoused the following view:
I am what is sometimes known as a "qualia freak". I think that there are certain features of bodily sensations especially, but also of certain perceptual experiences, which no amount of purely physical information includes. Tell me everything physical there is to tell about what is going on in a living brain... you won't have told me about the hurtfulness of pains, the itchiness of itches, pangs of jealousy....
According to epiphenomenalism, mental states like Pierre's pleasurable experience—or, at any rate, their distinctive qualia—are epiphenomena; they are side-effects or by-products of physical processes in the body. If Pierre takes a second bite, it is not caused by his pleasure from the first; If Pierre says, "That was good, so I will take another bite", his speech act is not caused by the preceding pleasure. The conscious experiences that accompany brain processes are causally impotent. The mind might simply be a byproduct of other properties such as brain size or pathway activation synchronicity, which are adaptive.
Some thinkers draw distinctions between different varieties of epiphenomenalism. In Consciousness Explained , Daniel Dennett distinguishes between a purely metaphysical sense of epiphenomenalism, in which the epiphenomenon has no causal impact at all, and Huxley's "steam whistle" epiphenomenalism, in which effects exist but are not functionally relevant.
A large body of neurophysiological data seems to support epiphenomenalism. Some of the oldest such data is the Bereitschaftspotential or "readiness potential" in which electrical activity related to voluntary actions can be recorded up to two seconds before the subject is aware of making a decision to perform the action. More recently Benjamin Libet et al. (1979) have shown that it can take 0.5 seconds before a stimulus becomes part of conscious experience even though subjects can respond to the stimulus in reaction time tests within 200 milliseconds. The conclusions of this experiment have begun to receive some backlash and criticism, mainly by neuroscientists such as Peter Tse, who claim to show that the readiness potential has nothing to do with consciousness at all.Recent research on the Event Related Potential also shows that conscious experience does not occur until the late phase of the potential (P3 or later) that occurs 300 milliseconds or more after the event. In Bregman's auditory continuity illusion, where a pure tone is followed by broadband noise and the noise is followed by the same pure tone it seems as if the tone occurs throughout the period of noise. This also suggests a delay for processing data before conscious experience occurs. Popular science author Tor Nørretranders has called the delay the "user illusion", implying that we only have the illusion of conscious control, most actions being controlled automatically by non-conscious parts of the brain with the conscious mind relegated to the role of spectator.
The scientific data seem to support the idea that conscious experience is created by non-conscious processes in the brain (i.e., there is subliminal processing that becomes conscious experience). These results have been interpreted to suggest that people are capable of action before conscious experience of the decision to act occurs. Some argue that this supports epiphenomenalism, since it shows that the feeling of making a decision to act is actually an epiphenomenon; the action happens before the decision, so the decision did not cause the action to occur.
The most powerful argument against epiphenomenalism is that it is self-contradictory: if we have knowledge about epiphenomenalism, then our brains know about the existence of the mind, but if epiphenomenalism were correct, then our brains should not have any knowledge about the mind, because the mind does not affect anything physical.
However, some philosophers do not accept this as a rigorous refutation. For example, Victor Argonov states that epiphenomenalism is a questionable, but experimentally falsifiable theory. He argues that the personal mind is not the only source of knowledge about the existence of mind in the world. A creature (even a zombie) could have knowledge about mind and the mind-body problem by virtue of some innate knowledge.The information about mind (and its problematic properties such as qualia) could have been, in principle, implicitly "written" in the material world since its creation. Epiphenomenalists can say that God created immaterial mind and a detailed "program" of material human behavior that makes it possible to speak about the mind–body problem. That version of epiphenomenalism seems highly exotic, but it cannot be excluded from consideration by pure theory. However, Argonov suggests that experiments could refute epiphenomenalism. In particular, epiphenomenalism could be refuted if neural correlates of consciousness can be found in the human brain, and it is proven that human speech about consciousness is caused by them.
Some philosophers, such as Dennett, reject both epiphenomenalism and the existence of qualia with the same charge that Gilbert Ryle leveled against a Cartesian "ghost in the machine", that they too are category mistakes. A quale or conscious experience would not belong to the category of objects of reference on this account, but rather to the category of ways of doing things.
Functionalists assert that mental states are well described by their overall role, their activity in relation to the organism as a whole. "This doctrine is rooted in Aristotle's conception of the soul, and has antecedents in Hobbes's conception of the mind as a 'calculating machine', but it has become fully articulated (and popularly endorsed) only in the last third of the 20th century."In so far as it mediates stimulus and response, a mental function is analogous to a program that processes input/output in automata theory. In principle, multiple realisability would guarantee platform dependencies can be avoided, whether in terms of hardware and operating system or, ex hypothesi, biology and philosophy. Because a high-level language is a practical requirement for developing the most complex programs, functionalism implies that a non-reductive physicalism would offer a similar advantage over a strictly eliminative materialism.
Eliminative materialists believe "folk psychology" is so unscientific that, ultimately, it will be better to eliminate primitive concepts such as mind,desire and belief, in favor of a future neuro-scientific account. A more moderate position such as J. L. Mackie's error theory suggests that false beliefs should be stripped away from a mental concept without eliminating the concept itself, the legitimate core meaning being left intact.
Benjamin Libet's results are quotedin favor of epiphenomenalism, but he believes subjects still have a "conscious veto", since the readiness potential does not invariably lead to an action. In Freedom Evolves , Daniel Dennett argues that a no-free-will conclusion is based on dubious assumptions about the location of consciousness, as well as questioning the accuracy and interpretation of Libet's results. Similar criticism of Libet-style research has been made by neuroscientist Adina Roskies and cognitive theorists Tim Bayne and Alfred Mele.
Others have argued that data such as the Bereitschaftspotential undermine epiphenomenalism for the same reason, that such experiments rely on a subject reporting the point in time at which a conscious experience and a conscious decision occurs, thus relying on the subject to be able to consciously perform an action. That ability would seem to be at odds with early epiphenomenalism, which according to Huxley is the broad claim that consciousness is "completely without any power… as the steam-whistle which accompanies the work of a locomotive engine is without influence upon its machinery".
Adrian G. Guggisberg and Annaïs Mottaz have also challenged those findings.
A study by Aaron Schurger and colleagues published in PNASchallenged assumptions about the causal nature of the readiness potential itself (and the "pre-movement buildup" of neural activity in general), thus denying the conclusions drawn from studies such as Libet's and Fried's.
In favor of interactionism, Celia Green (2003) argues that epiphenomenalism does not even provide a satisfactory solution to the problem of interaction posed by substance dualism. Although it does not entail substance dualism, according to Green, epiphenomenalism implies a one-way form of interactionism that is just as hard to conceive of as the two-way form embodied in substance dualism. Green suggests the assumption that it is less of a problem may arise from the unexamined belief that physical events have some sort of primacy over mental ones.
A number of scientists and philosophers, including William James, Karl Popper, John C. Eccles and Donald Symons, dismiss epiphenomenalism from an evolutionary perspective.They point out that the view that mind is an epiphenomenon of brain activity is not consistent with evolutionary theory, because if mind were functionless, it would have disappeared long ago, as it would not have been favoured by evolution.
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Free will is the ability to choose between different possible courses of action unimpeded.
An epiphenomenon is a secondary phenomenon that occurs alongside or in parallel to a primary phenomenon. The word has two senses: one that connotes known causation and one that connotes absence of causation or reservation of judgment about it.
Consciousness Explained is a 1991 book by the American philosopher Daniel Dennett, in which the author offers an account of how consciousness arises from interaction of physical and cognitive processes in the brain.
Mind–body dualism is the view in the philosophy of mind that mental phenomena are non-physical, or that the mind and body are distinct and separable. Thus, it encompasses a set of views about the relationship between mind and matter, and between subject and object, and is contrasted with other positions, such as physicalism and enactivism, in the mind–body problem.
In philosophy of mind and consciousness, the explanatory gap is the difficulty that physicalist theories have in explaining how physical properties give rise to the way things feel when they are experienced. It is a term introduced by philosopher Joseph Levine. In the 1983 paper in which he first used the term, he used as an example the sentence, "Pain is the firing of C fibers", pointing out that while it might be valid in a physiological sense, it does not help us to understand how pain feels.
Eliminative materialism is the claim that people's common-sense understanding of the mind is false and that certain classes of mental states that most people believe in do not exist. It is a materialist position in the philosophy of mind. Some supporters of eliminativism argue that no coherent neural basis will be found for many everyday psychological concepts such as belief or desire, since they are poorly defined. Rather, they argue that psychological concepts of behaviour and experience should be judged by how well they reduce to the biological level. Other versions entail the non-existence of conscious mental states such as pain and visual perceptions.
The knowledge argument is a philosophical thought experiment proposed by Frank Jackson in his article "Epiphenomenal Qualia" (1982) and extended in "What Mary Didn't Know" (1986). The experiment is intended to argue against physicalism—the view that the universe, including all that is mental, is entirely physical. The debate that emerged following its publication became the subject of an edited volume—There's Something About Mary (2004)—which includes replies from such philosophers as Daniel Dennett, David Lewis, and Paul Churchland.
The hard problem of consciousness is the problem of explaining why and how sentient organisms have qualia or phenomenal experiences—how and why it is that some internal states are subjective, felt states, such as heat or cold, rather than objective states, as in the workings of a thermostat or a toaster. The philosopher David Chalmers, who introduced the term "hard problem" of consciousness, contrasts this with the "easy problems" of explaining the ability to discriminate, integrate information, report mental states, focus attention, and so forth. Easy problems are (relatively) easy because all that is required for their solution is to specify a mechanism that can perform the function. That is, regardless of how complex or poorly understood the phenomena of the easy problems may be, they can eventually be understood by relying entirely on standard scientific methodologies. Chalmers claims that the problem of experience is distinct from this set and will "persist even when the performance of all the relevant functions is explained".
The philosophical zombie or p-zombie argument is a thought experiment in philosophy of mind and philosophy of perception that imagines a being that, if it could conceivably exist, logically disproves the idea that physical substance is all that is required to explain consciousness. Such a zombie would be indistinguishable from a normal human being but lack conscious experience, qualia, or sentience. For example, if a philosophical zombie were poked with a sharp object it would not inwardly feel any pain, yet it would outwardly behave exactly as if it did feel pain. The thought experiment sometimes takes the form of imagining a zombie world, indistinguishable from our world, but lacking first person experiences in any of the beings of that world.
Daniel Dennett's multiple drafts model of consciousness is a physicalist theory of consciousness based upon cognitivism, which views the mind in terms of information processing. The theory is described in depth in his book, Consciousness Explained, published in 1991. As the title states, the book proposes a high-level explanation of consciousness which is consistent with support for the possibility of strong AI.
Benjamin Libet was a pioneering scientist in the field of human consciousness. Libet was a researcher in the physiology department of the University of California, San Francisco. In 2003, he was the first recipient of the Virtual Nobel Prize in Psychology from the University of Klagenfurt, "for his pioneering achievements in the experimental investigation of consciousness, initiation of action, and free will".
Property dualism describes a category of positions in the philosophy of mind which hold that, although the world is composed of just one kind of substance—the physical kind—there exist two distinct kinds of properties: physical properties and mental properties. In other words, it is the view that non-physical, mental properties exist in, or naturally supervene upon, certain physical substances.
In the philosophy of mind, the China brain thought experiment considers what would happen if each member of the Chinese nation were asked to simulate the action of one neuron in the brain, using telephones or walkie-talkies to simulate the axons and dendrites that connect neurons. Would this arrangement have a mind or consciousness in the same way that brains do?
In philosophy of mind, Cartesian materialism is the idea that at some place in the brain, there is some set of information that directly corresponds to our conscious experience. Contrary to its name, Cartesian materialism is not a view that was held by or formulated by René Descartes, who subscribed rather to a form of substance dualism.
Philosophy of mind is a branch of philosophy that studies the ontology and nature of the mind and its relationship with the body. The mind–body problem is a paradigmatic issue in philosophy of mind, although a number of other issues are addressed, such as the hard problem of consciousness and the nature of particular mental states. Aspects of the mind that are studied include mental events, mental functions, mental properties, consciousness, the ontology of the mind, the nature of thought, and the relationship of the mind to the body.
"What Is It Like to Be a Bat?" is a paper by American philosopher Thomas Nagel, first published in The Philosophical Review in October 1974, and later in Nagel's Mortal Questions (1979), which presents several difficulties posed by consciousness, including the possible insolubility of the mind-body problem owing to “facts beyond the reach of human concepts”, the limits of objectivity and reductionism, the “phenomenological features” of subjective experience, the limits of human imagination, and what it means to be a particular, conscious thing. Nagel famously asserts that “an organism has conscious mental states if and only if there is something that it is like to be that organism—something it is like for the organism." This assertion has achieved special status in consciousness studies as “the standard ‘what it’s like’ locution.” Daniel Dennett, while sharply disagreeing on some points, acknowledged Nagel’s paper as "the most widely cited and influential thought experiment about consciousness." Peter Hacker analyzes Nagel’s statement as not only “malconstructed” but philosophically “misconceived” as a definition of consciousness, and he asserts that Nagel’s paper “laid the groundwork for…forty years of fresh confusion about consciousness.”
The mind–body problem is a debate concerning the relationship between thought and consciousness in the human mind, and the brain as part of the physical body. It is distinct from the question of how mind and body function chemically and physiologically, as that question presupposes an interactionist account of mind–body relations. This question arises when mind and body are considered as distinct, based on the premise that the mind and the body are fundamentally different in nature.
In philosophy and certain models of psychology, qualia are defined as individual instances of subjective, conscious experience. The term qualia derives from the Latin neuter plural form (qualia) of the Latin adjective quālis meaning "of what sort" or "of what kind" in a specific instance, such as "what it is like to taste a specific apple, this particular apple now".
Interactionism or interactionist dualism is the theory in the philosophy of mind which holds that matter and mind are two distinct and independent substances that exert causal effects on one another. It is one type of dualism, traditionally a type of substance dualism though more recently also sometimes a form of property dualism.
The concept of absent qualia is one of two major Functionalist objections to the existence of qualia, the other being the inverted spectrum hypothesis. Qualia is a philosophical term used to refer to an individual's subjective experience, that is to say, the way something feels to that individual at that particular moment.