identity theory of mind

Type physicalism (also known as Type Identity Theory, Mind-Brain Identity Theory and Identity Theory of Mind) is a theory, in philosophy of mind, which asserts that mental events are type-identical to the physical events in the brain with which they are correlated. The thesis of type physicalism is that mental event types (for example, pains) are identical, perhaps contingently, with specific physical event types in the brain (for example, C-fiber firings).

It is called type identity in order to distinguish it from a similar but distinct theory called the token identity theory. The type-token distinction is easily illustrated by way of example. In the phrase "yellow is yellow is yellow is yellow", there are only two types of words ("yellow" and "is") but there are seven tokens (four "yellow" and three "is" tokens).

Background

According to U.T. Place (unpublished), one of the popularizers of the idea of type-identity in the 1950s and 1960s, the idea of type-identity physicalism originated in the 1930s with the psychologist E. G. Boring and took nearly a quarter of a century to finally catch on and become accepted by the philosophical community. Boring, in a book entitled The Physical Dimensions of Consciousness (1933) wrote that:

To the author a perfect correlation is identity. Two events that always occur together at the same time in the same place, without any temporal or spatial differentiation at all, are not two events but the same event. The mind-body correlations as formulated at present, do not admit of spatial correlation, so they reduce to matters of simple correlation in time. The need for identification is no less urgent in this case (p. 16, quoted in Place [unpublished]).


The barrier to the acceptance of any such vision of the mind, according to Place, was that philosophers and logicians had not yet taken a substantial interest in questions of identity and referential identification in general. The dominant epistemology of the logical positivists at that time was phenomenalism, in the guise of the theory of sense-data. Indeed Boring himself subscribed to the phenomenalist creed, attempting to reconcile it with an identity theory and this resulted in a reductio ad absurdum of the identity theory, since brain states would have turned out, on this analysis, to be identical to colors, shapes, tones and other sensory experiences.

The revival of interest in the work of Gottlob Frege and his ideas of sense and reference on the part of Herbert Feigl and J.J.C. Smart, along with the discrediting of phenomenalism through the influence of the later Wittgenstein and J.L. Austin, led to a more tolerant climate toward physicalistic and realist ideas. Logical behaviorism emerged as a serious contender to take the place of the Cartesian "ghost in the machine" and, although not lasting very long as a dominant position on the mind/body problem, its elimination of the whole realm of internal mental events was strongly influential in the formation and acceptance of the thesis of type identity.

Versions of type identity theory

There were actually subtle but interesting differences between the three most widely credited formulations of the type-identity thesis, those of Place, Feigl and Smart which were published in several articles in the late 1950s. However, all of the versions share the central idea that the mind is identical to something physical.

U.T. Place

U.T. Place's (1956) notion of the relation of identity was derived from Bertrand Russell's distinction among several types of is statements: the is of identity, the is of equality and the is of composition. Place's version of the relation of identity is more accurately described as a relation of composition. For Place, higher-level mental events are composed out of lower-level physical events and will eventually be analytically reduced to these. So, to the objection that "sensations" do not mean the same thing as "mental processes", Place could simply reply with the example that "lightning" does not mean the same thing as "electrical discharge" since we determine that something is lightning by looking and seeing it, whereas we determine that something is an electrical discharge through experimentation and testing. Nevertheless, "lightning is an electrical discharge" is true since the one is composed of the other.

Feigl and Smart

For Feigl (1957) and Smart (1959), on the other hand, the identity was to be interpreted as the identity between the referents of two descriptions (senses) which referred to the same thing, as in "the morning star" and "the evening star" both referring to Venus. So to the objection about the lack of equality of meaning between "sensation" and "brain process", their response was to invoke this Fregean distinction: "sensations" and "brain" processes do indeed mean different things but they refer to the same physical phenomenon. Moreover, "sensations are brain processes" is a contingent, not a necessary, identity.

Criticism and replies

Multiple realizability

One of the most influential and common objections to the type identity theory is the argument from multiple realizability. The multiple realizability thesis asserts that mental states can be realized in multiple kinds of systems, not just brains, for example. Since the identity theory identifies mental events with certain brain states, it does not allow for mental states to be realized in organisms or computational systems that do not have a brain. This is in effect an argument that the identity theory is too narrow (often called chauvinistic) because it does not allow for non-humans to have mental states. However, token identity (where only particular tokens of mental states are identical with particular tokens of physical events) and functionalism both account for multiple realizability.

The response of type identity theorists, such as Smart, to this objection is that, while it may be true that mental events are multiply realizable, this does not demonstrate the falsity of type identity. As Smart states:

"The functionalist second order [causal] state is a state of having some first order state or other which causes or is caused by the behavior to which the functionalist alludes. In this way we have a second order type theory."


The fundamental point is that it is extremely difficult to determine where, on the continuum of first order processes, type identity ends and merely token identities begin. Take Quine's example of English country gardens. In such gardens, the tops of hedges are cut into various shapes, for example the shape of an elf. We can make generalizations over the type elf-shaped hedge only if we abstract away from the concrete details of the individual twigs and branches of each hedge. So, whether we say that two things are of the same type or are tokens of the same type because of subtle differences is just a matter of descriptive abstraction. The type-token distinction is not all or nothing.

Hilary Putnam responds to Smart's response by essentially rejecting functionalism because, he believes, it is indeed a second-order type identity theory. Putnam uses multiple realizability against functionalism itself, suggesting that mental events (or kinds, in Putnam's terminology) may be diversely implemented by diverse functional/computational kinds; there may be only a token identification between particular mental kinds and particular functional kinds. Putnam, and many others who have followed him, now tend to identify themselves as generically non-reductive physicalists. Putnam's invocation of multiple realizability does not, of course, directly answer the problem raised by Smart with respect to useful generalizations over types and the flexible nature of the type-token distinction in relation to causal taxonomies in science. (See multiple realizability for a more in-depth discussion of these issues.)

Qualia

Another frequent objection is that type identity theories fail to account for phenomenal mental states (or qualia), such as having a pain, feeling sad, experiencing nausea. (Qualia are merely the subjective qualities of conscious experience. An example is the way the pain of jarring your elbow feels to you.) Arguments can be found in Saul Kripke (1972) and David Chalmers (1996), for example, according to which the identity theorist cannot identify phenomenal mental states with brain states (or any other physical state for that matter) because one has a sort of direct awareness of the nature of such qualitative mental states, and their nature is qualitative in a way that brain states are not.

A famous formulation of the qualia objection comes from Frank Jackson (1982) in the form of the wonderfully vivid Mary's room thought experiment. Let us suppose, Jackson suggests, that a particularly brilliant super-scientist named Mary has been locked away in a completely black-and-white room her entire life. Over the years in her colour-deprived world she has studied (via black-and-white books and television) the sciences of neurophysiology, vision and electromagnetics to their fullest extent; eventually Mary comes to know all the physical facts there are to know about experiencing colour. When Mary is released from her room and experiences colour for the first time, does she learn something new? If we answer "yes" (as Jackson suggests we do) to this question, then we have supposedly denied the truth of type physicalism, for if Mary has exhausted all the physical facts about experiencing colour prior to her release, then her subsequently acquiring some new piece of information about colour upon experiencing its quale reveals that there must be something about the experience of colour which is not captured by the physicalist picture. (See Mary's room page for full discussion).

The type identity theorist, such as Smart, attempts to explain away such phenomena by insisting that the experiential properties of mental events are topic-neutral. The concept of topic-neutral terms and expressions goes back to Gilbert Ryle, who identified such topic-neutral terms as "if", "or", "not", "because" and "and." If one were to hear these terms alone in the course of a conversation, it would be impossible to tell whether the topic under discussion concerned geology, physics, history, gardening or selling pizza. For the identity theorist, sense-data and qualia are not real things in the brain (or the physical world in general) but are more like "the average electrician." The average electrician can be further analyzed and explained in terms of real electricians but is not itself a real electrician.

See also

References and further reading

  • Chalmers, David (1996). The Conscious Mind, Oxford University Press, New York.
  • Feigl, Herbert (1958). "The 'Mental' and the 'Physical'" in Feigl, H., Scriven, M. and Maxwell, G. (eds.) Concepts, Theories and the Mind-Body Problem, Minneapolis, Minnesota Studies in the Philosophy of Science, Vol. 2, reprinted with a Postscript in Feigl 1967.
  • Feigl, Herbert (1967). The 'Mental' and the 'Physical', The Essay and a Postscript, Minneapolis, University of Minnesota Press.
  • Jackson, Frank (1982) "Epiphenomenal Qualia", Philosophical Quarterly 32, pp. 127-136.
  • Kripke, Saul (1972/1980). Naming and Necessity, Cambridge, Mass., Harvard University Press. (Originally published in 1972 as "Naming and Necessity".)
  • Lewis, David (1966). "An Argument for the Identity Theory", Journal of Philosophy, 63, pp. 17-25.
  • Lewis, David (1980). "Mad Pain and Martian Pain" in Readings in the Philosophy of Psychology, Vol. I, N. Block (ed.), Harvard University Press, pp. 216-222. (Also in Lewis's Philosophical Papers, Vol. 1, Oxford University Press, 1983.)
  • Place, U.T. (1956). "Is Consciousness a Brain Process?", British Journal of Psychology, 47, pp. 44-50.
  • Place, U.T. (unpublished). "Identity Theories", A Field Guide to the Philosophy of Mind. Società italiana per la filosofia analitica, Marco Nanni (ed.). (link)
  • Putnam, Hilary (1988). Representation and Reality. The MIT Press.
  • Smart, J.J.C. (1959). "Sensations and Brain Processes", Philosophical Review, 68, pp. 141-156.
  • Smart, J.J.C. (2004). "The Identity Theory of Mind", The Stanford Encyclopedia of Philosophy (Fall 2004 Edition), Edward N. Zalta (ed.). (link)

External links

Philosophy of mind is the branch of philosophy that studies the nature of the mind, mental events, mental functions, mental properties, consciousness and their relationship to the physical body. The mind-body problem, i.e.
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A mental event is a particular occurrence of something going on in the mind or mind substitute. It can be a thought, a dream, a feeling, a realization, or any other mental activity.
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correlation, also called correlation coefficient, indicates the strength and direction of a linear relationship between two random variables. In general statistical usage, correlation or co-relation refers to the departure of two variables from independence.
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Physicalism is a philosophical position holding that everything which exists is no more extensive than its physical properties; that is, that there are no kinds of things other than physical things.
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Anomalous monism is a philosophical thesis about the mind-body relationship. It was first proposed by Donald Davidson in his 1970 paper Mental events. The theory is twofold and states that mental events are identical with physical events (this is physicalism, a form of
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Ullin Place (1924 – 2000) was a British philosopher and psychologist. Along with J. J. C. Smart, he developed the identity theory of mind. Place was born in Yorkshire and studied under Gilbert Ryle at Oxford University.
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Edwin Garrigues Boring (October 23, 1886-July 1, 1968) was an experimental psychologist who later became one of the first historians of psychology.

From 1924 to 1949 Boring was director of the psychological laboratory at Harvard University, where his goal became to free
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Epistemology or theory of knowledge is the branch of philosophy that studies the nature, methods, limitations, and validity of knowledge and belief.

The term "epistemology" is based on the Greek words "
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Logical positivism grew from the discussions of Moritz Schlick's Vienna Circle and Hans Reichenbach's Berlin Circle in the 1920s and 1930s. The movement is known for its espousal of verificationism, its admiration for science and technical rigor, and its commitment to the
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In epistemology and the philosophy of perception, phenomenalism is the view that physical objects do not exist as things in themselves but only as perceptual phenomena or sensory stimuli (e.g. redness, hardness, softness, sweetness, etc.) situated in time and in space.
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Friedrich Ludwig Gottlob Frege
Birth: November 8, 1848
Death: 26 July, 1925
School/tradition: Analytic philosophy
Main interests: Philosophy of mathematics, mathematical logic, Philosophy of language
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Senses are the physiological methods of perception. The senses and their operation, classification, and theory are overlapping topics studied by a variety of fields, most notably neuroscience, cognitive psychology (or cognitive science), and philosophy of perception.
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reference is a relation between objects in which one object designates, or acts as a means by which to connect to or link to, another object. Such relations may occur in a variety of domains, including linguistics, logic, computer science, art, and scholarship.
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Herbert Feigl (December 14, 1902 – June 1, 1988) was an Austrian philosopher and a member of the Vienna Circle.

The son of a weaver, Feigl was born in Reichenberg (Liberec), Bohemia, and matriculated at the University of Vienna in 1922.
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John Jamieson Carswell Smart, AC or Jack Smart (born 1920) is a Scottish philosopher who lives in Melbourne, Australia. He works in the fields of metaphysics, philosophy of mind, philosophy of religion, and political philosophy.
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Ludwig Josef Johann Wittgenstein (IPA: ['luːtvɪç 'joːzɛf 'joːhan 'vɪtgənʃtaɪn]
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John Langshaw Austin (March 28, 1911 – February 8, 1960) was a British philosopher of language, born in Lancaster and educated at Balliol College, Oxford University. Austin is widely associated with the concept of the speech act and the idea that speech is itself a form of
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Behaviorism (also called learning perspective) is a philosophy of psychology based on the proposition that all things which organisms do — including acting, thinking and feeling—can and should be regarded as behaviors.
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Bertrand Arthur William Russell, 3rd Earl Russell, OM, FRS, (18 May 1872 – 2 February 1970), was a British philosopher, historian, logician, mathematician, advocate for social reform, pacifist, and prominent rationalist.
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In philosophy, identity is whatever makes an entity definable and recognizable, in terms of possessing a set of qualities or characteristics that distinguish it from entities of a different type. Or, in layman's terms, identity is whatever makes something the or .
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Multiple realizability, in philosophy of mind, is the thesis that the same mental property, state, or event can be implemented by different physical properties, states or events.
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Functionalism is a theory of the mind in contemporary philosophy, developed largely as an alternative to both the identity theory of mind and behaviorism.
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Hilary Whitehall Putnam (born July 31 1926) is an American philosopher who has been a central figure in Western philosophy since the 1960s, especially in philosophy of mind, philosophy of language, and philosophy of science.
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Multiple realizability, in philosophy of mind, is the thesis that the same mental property, state, or event can be implemented by different physical properties, states or events.
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Qualia" (IPA: [ˈkwɑːliə]) is "an unfamiliar term for something that could not be more familiar to each of us: the ways things seem to us"[1].
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Consciousness is a characteristic of the mind generally regarded to comprise qualities such as subjectivity, self-awareness, sentience, sapience, and the ability to perceive the relationship between oneself and one's environment.
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Frank Jackson may refer to:
  • Frank Cameron Jackson (born 1943), a professor of philosophy at the Australian National University
  • Frank Lawson John Jackson (1919–1976), British Conservative Member of Parliament (MP) 1959–1964
  • Frank G.

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Mary's room (also known as Mary the super-scientist) is a philosophical thought experiment proposed by Frank Jackson in his article "Epiphenomenal Qualia" (1982) and extended in "What Mary Didn't Know" (1986).
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Qualia" (IPA: [ˈkwɑːliə]) is "an unfamiliar term for something that could not be more familiar to each of us: the ways things seem to us"[1].
..... Click the link for more information.
Mary's room (also known as Mary the super-scientist) is a philosophical thought experiment proposed by Frank Jackson in his article "Epiphenomenal Qualia" (1982) and extended in "What Mary Didn't Know" (1986).
..... Click the link for more information.


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