Epiphenomenalism is a philosophical theory on the mind–body problem in the philosophy of mind. It holds that subjective are completely dependent for their existence on corresponding physical and biochemical events within the human body, but do not themselves influence physical events. According to epiphenomenalism, the appearance that subjective mental states (such as and ) are causally effective themselves and directly influence physical events is an illusion generated by brain regions such as the prefrontal cortex, with consciousness itself being a by-product of physical states of the world. For instance, the emotion of fear seems to make the heart beat faster, but according to epiphenomenalism the biochemical secretions of the brain and nervous system (such as the stress hormone adrenaline)—not the subjective experience of fear itself—is what causes the rapid rise in heartbeat. Because mental events are a kind of overflow that cannot cause anything physical, yet have non-physical properties, epiphenomenalism has traditionally been viewed as a form of property dualism. In contemporary thought, there are a number of epiphenomenalistic questions that arise within a broadly materialist monism.[Robinson, William, "Epiphenomenalism"
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Development
During the 17th century, René Descartes argued that 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.[Huxley, T. H. (1874). "On the Hypothesis that Animals are Automata, and its History", The Fortnightly Review, n.s.16:555–580. Reprinted in Method and Results: Essays by Thomas H. Huxley (New York: D. Appleton and Company, 1898)][Gallagher, S. 2006. "Where's the action?: Epiphenomenalism and the problem of free will". In W. Banks, S. Pockett, and S. Gallagher. Does Consciousness Cause Behavior? An Investigation of the Nature of Intuition (109–124). Cambridge, Massachusetts: MIT Press.]
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 based on his experiments showing that movement was still possible without certain parts of the central nervous system being intact. Based on these results, Huxley proposed that consciousness itself was not in control of an animal's behavior, concluding that psychical changes are collateral products of physical changes. 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 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.
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.
Frank Cameron Jackson (1982), for example, once espoused the following view:
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.
Arguments for
Some neurophysiological data has been proffered in support of epiphenomenalism, suggesting that at least some choices and actions appear to be actually controlled by subconscious brain processes for which the conscious mind later takes credit. 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 methods and conclusions of this experiment have received much criticism (e.g., see the many critical commentaries in Libet's (1985) target article), including fairly recently by such as Peter Tse, who claim to show that the readiness potential has nothing to do with consciousness at all.
Arguments against
One 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, philosopher 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 philosophical zombie) could have knowledge about the mind and the mind-body problem by virtue of some innate knowledge.
Some philosophers, such as Daniel Dennett, reject both epiphenomenalism and the existence of qualia with the same charge that Gilbert Ryle leveled against a Cartesianism "ghost in the machine", that they too are . 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."
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 neuroscientific 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 quoted[Daniel Wegner, 2002. The Illusion of Conscious Will. Cambridge, Massachusetts: MIT Press.] in 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.[Dennett, Daniel. (2003) Freedom evolves.] 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 PNAS
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 perspective.
See also
Notes
Further reading
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Chalmers, David. (1996) The Conscious Mind: In Search of a Fundamental Theory, Oxford: Oxford University Press.
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Green, Celia. (2003) The Lost Cause: Causation and the Mind-Body Problem, Oxford: Oxford Forum.
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Jackson, Frank. (1982) "Epiphenomenal Qualia", The Philosophical Quarterly, 32, pp. 127–136. Online text
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James, William. (1890) The Principles of Psychology, Henry Holt And Company. Online text
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Robinson, William (2019) Epiphenomenal Mind: An Integrated Outlook on Sensations, Beliefs, and Pleasure, New York and London: Routledge.
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