Philosophy of Mind

Neutral Monism

A mind-body theory that claims that fundamentally everything is neither mentally nor physical but neutral. It's defenders include the philosophers William James and Bertrand Russell. Neutral monism has been a marginal view in philosophy of mind largely because its exponents have failed to provide an informative definition of neutral phenomena.

Substance Dualism

A mind-body theory that endorses property dualism but denies psychophysical coincidence. There are two different kinds of properties and two different kinds of individuals or substances having those properties. Individuals having only mental properties, and individuals having only physical properties. By itself, substance dualism does not specify how persons and bodies are related, so there are interactionist and non-interactionist forms of it. Substance dualists defend their theory by appeal to a modal argument.

Qualia / Phenomenal Consciousness

A Latin word that means qualities. The corresponding singular term is 'quale'. Qualia are supposed to be the qualitative or phenomenal features of conscious experiences. Paradigmatic examples include sensations and pains. The philosopher Thomas Nagel introduced the expression 'what it's like' to refer to qualia. There is something it's like to experience a pain, or a flavor, or an odor. What it's like cannot be expressed verbally, say many exponents of qualia; to know what something is like someone must experience it him or herself. Critics of physicalism and similar theories often appeal to qualia. Examples of their arguments include the knowledge argument, and other qualia-based arguments, as well as the argument for epiphenomenalism. There are several arguments against the existence of qualia including the argument for eliminative physicalism, the appeal to ontological naturalism, Dennett's argument against qualia, and Wittgenstein's private language argument.

Turing machine

A Turing machine is an abstract description of an input-output system. It is named after Alan Turing, and is the basis of functionalist thinking about the mind.

Artificial Intelligence (AI)

A branch of cognitive science that tries to construct artificial systems that either have intelligence or simulate intelligence. The idea that such systems would only simulate intelligence is known as Weak AI; the idea that they would actually have intelligence is known as Strong AI. John Searle has argued against Strong AI by appeal to the Chinese room argument.

Embodiment thesis

A claim endorsed by a hylomorphic theory of mind: human psychological capacities are essentially embodied. They cannot be defined without reference to the bodily parts humans possess. Embodiment has implications for how hylomorphists understand multiple realizability. We can apply psychological predicates and terms to nonhumans, they say, not because psychological capacities are defined abstractly as, say, functionalists claim, but because we are able to draw analogies between the behavior and body plans of nonhuman things and our own.

Semicompatibilism

A compatibilist theory that grounds moral responsibility in exercising the right kind of control over actions. Unlike other compatibilist theories, however, semicompatibilism denies that free will is compatible with determinism. Semicompatibilists thus deny that moral responsibility requires free will. Critics argue that semicompatibilism fails to capture our intuitions about what constitutes moral responsibility.

Exclusion argument

A criticism of emergentism and nonreductive physicalism. 1 Actions have mental causes. 2 Actions have physical causes. 3 Mental causes and physical causes are distinct. 4 An action does not have more than one cause. Nonreductive physicalist cannot reject (1) or (4) without rejecting the causal efficacy of mental events; they cannot reject (2) without rejecting their commitment to physicalism, and they cannot reject (3) without rejecting their commitment to anti-reductivism.

Type-token distinction

A distinction originally drawn by the American philosopher Charles Sanders Peirce (1839-1914). A type is a general category and individual tokens are its members. The five quarters in my pocket are five tokens of a single type. In philosophy of mind the type-token distinction is often used as a way of describing the difference between reductive physicalism and nonreductive physicalism. See type versus token physicalism.

Verifiability theory of meaning

A doctrine of logical positivism. It claims that the meaning of a statement consists in its verification conditions, the conditions sufficient for knowing that the statement is true. According to logical positivists, statements could be verified in only two ways: empirically through scientific investigation, or analytically by analyzing the meaning of the statement's predicates and terms. Utterances that could not be verified in either way were meaningless, according to positivists. The verifiability theory of meaning was discredited for several reasons, not the least of which was that it was selfreferentially incoherent: it did not satisfy its own criterion of meaningfulness since the claim that the meaning of a statement consists in its verification conditions can be verified neither empirically nor analytically.

Epiphenomenalism

A dual-attribute theory that claims mental properties are caused by something's physical properties, and that mental properties cannot causally influence anything in turn. Contemporary epiphenomenalist theories claim that qualia, and in general mental states that conform to a private conception of mental phenomena, are epiphenomenal, but that propositional attitudes and mental states that conform to a public conception of mental phenomena are not epiphenomenal but are identical to physical states as the psychophysical identity theory claims.

Emergentism

A dual-attribute theory that claims, like epiphenomenalism, that mental properties are produced by or emerge out of physical interactions. Unlike epiphenomenalists, however, emergentists claim that mental properties exert a causal influence on physical things. Emergentists argue that their theory is the best explanation for certain empirical facts. Critics deny this, and argue that emergentism faces the problem of psychophysical emergence, and the problem of mental causation.

Realization

A relation between abstract and concrete descriptions or things. An abstract object such as a rectangle is said to be realized in a piece of wood or metal. Likewise, an abstract procedure such as an algorithm is said to be realized in the gears or circuits of a calculator. According to functionalism, mental properties are abstract properties; they are higher-order properties that are realized by lower-order properties. My beliefs, desires, pains, and other mental states are realized by states of the brain, for instance. If mental states can also be realized in other kinds of things, then they are multiply realizable.

Nonreductive physicalism

A family of physicalist theories that reject the reduction of the special sciences to physics. Unlike eliminative physicalists and like reductive physicalists, nonreductive physicalists claim that psychological discourse has real descriptive and explanatory legitimacy. Unlike reductive physicalists, however, nonreductivists deny that this legitimacy is due to psychological categories corresponding in a straightforward way to physical categories. It is due instead to psychological categories satisfying special interests we have. We have many different descriptive and explanatory interests. Physics satisfies some of them, but it cannot satisfy all; only the special sciences can. As a result, physics cannot take over the descriptive and explanatory roles the special sciences play. Hence, the special sciences are not reducible to physics. Dual-attribute theories deny the reducibility of the special sciences to physics as well, but for different reasons. Unlike nonreductive physicalist theories, they deny that all properties are physical. Because nonreductive physicalism is committed to rejecting reductivism, and because some forms of it distinguish between higher-order and lower-order properties, it is sometimes characterized as a form of property dualism, but this label is misleading at best. Nonreductive physicalism is committed to physicalism, a form of monism. It implies that all properties are physical, and is thus incompatible with property dualism. The label 'nonreductive physicalism' has also been used to describe any view that (1) rejects reductivism yet (2) implies that we are composed entirely of physical particles. This too is a misleading label since many nonphysicalist theories endorse (1) and (2) including hylomorphism and dual-attribute theories such as emergentism and epiphenomenalism. Varieties of nonreductive physicalism include realization physicalism, supervenience physicalism, and anomalous monism. Nonreductive physicalism was inspired by arguments against the psychophysical identity theory such as the multiple-realizability argument.

Compatibilism

A family of solutions to the problem of free will and determinism that claim the existence of moral responsibility is compatible with determinism. Classic compatibilist theories claim that free will and moral responsibility require the ability to do otherwise, and that this ability is compatible with determinism. Contemporary compatibilist theories deny that moral responsibility requires the ability to do otherwise by appeal to Frankfurttype examples. Contemporary compatibilist theories include hierarchical theories, capacitybased theories, reactive attitude theories, and semicompatibilist theories.

Causal indeterminism

A form of libertarianism that claims that actions are caused indeterministically. Antecedent conditions such as an agent's beliefs and desires make the occurrence of an action more probable, but do not determine it; that is, they do not bring it about with a probability of 1. Critics allege that causal indeterminist theories face a problem with control: if an agent's actions are not determined by the agent's beliefs and desires, then the agent is not completely in control of their occurrence, and in that case the agent cannot be held morally accountable for them.

Anomalous monism

A form of nonreductive physicalism originally formulated by Donald Davidson. It claims that everything is physical, and that psychological discourse is anomalous; that is, there are no laws that can be formulated using a psychological vocabulary. This implies both that there are no laws featuring exclusively mental predicates, and that there are no laws featuring mental predicates in combination with physical predicates. Because psychophysical reduction requires lawlike connections between mental and physical states, it requires laws featuring mental predicates in combination with physical predicates. Consequently, anomalous monism rejects the possibility of psychophysical reduction. Mental states nevertheless cause physical states, it says, so if causal relations must be underwritten by laws, it follows that there must be laws linking mental states with physical states. Since these laws cannot be formulated in a psychological vocabulary, they must be formulated in a physical vocabulary, and that means that mental states must have physical descriptions; that is, they must be physical states.

Supervenience physicalism

A form of nonreductive physicalism that claims that special scientific phenomena supervene on physical phenomena. Supervenience physicalism faces several serious problems and has been forcefully criticized by Jaegwon Kim.

Realization physicalism

A form of nonreductive physicalism that combines physicalism with functionalism. Realization physicalism claims mental properties, and special scientific properties generally, are realized by lower-level properties. Higher-level properties, it says, are higher-order properties, logical constructions that quantify over other properties. Arguments against realization physicalism include Kim's trilemma and the exclusion argument, as well as arguments that target functionalism and physicalism.

Reductive physicalism

A form of physicalism that claims that psychological categories correspond to physical categories in some straightforward way. Examples include the psychophysical identity theory and logical behaviorism. According to reductivists, for instance, what we call 'pain' is really just a physical state such as a state of the brain. The mental and physical conceptual frameworks are just two different frameworks for describing the very same things. By contrast, eliminative physicalists deny that terms such as 'pain' refer to anything in reality, and nonreductive physicalists deny that psychological categories correspond to physical categories in a straightforward way. Reductive physicalism gets its name because it implies psychophysical reduction; it implies that physical discourse can take over the descriptive and explanatory roles of psychological discourse.

Eliminative physicalism

A form of physicalism that denies that psychological discourse has any descriptive or explanatory legitimacy. In reality, say eliminativists, there are no beliefs, desires, hopes, joys, or pains. Trying to describe and explain human behavior by appeal to mental states is like trying to describe and explain the weather by appeal to the Greek gods: it is the byproduct of a defective conceptual framework that may have been useful at one time, but that will be eliminated as soon as a complete scientific understanding of human behavior is achieved (hence the label 'eliminative'). By contrast, reductive and nonreductive physicalism claim that psychological discourse does have descriptive and explanatory legitimacy.

Ability hypothesis

A response to the knowledge argument. Exponents of the ability hypothesis deny that Mary learns a new fact when she sees a ripe tomato for the first time; she instead gains a new ability.

Logical positivism

A movement in early-twentieth-century philosophy. Positivists in general saw human history as progressing through stages: the religious stage was followed by the philosophical or metaphysical stage, and that stage was followed by the scientific stage. Initiators of each new stage had to struggle to move human understanding past the preceding stage. Logical positivists took themselves to be contributors to the effort to move human understanding beyond the philosophical/metaphysical stage using the logical and linguistic tools developed by the logician and mathematician Gottlob Frege (1848 1925), and the philosophers Bertrand Russell and Ludwig Wittgenstein. The positivist movement had its heyday in the 1930s and 1940s, but by the early 1950s it was moribund. Logical behaviorism was the branch of positivist philosophy that dealt with mind-body problems.

The Problem of Psychophysical Emergence

A philosophical problem posed by the following claims: (1) we are conscious beings; (2) we are composed entirely of nonconscious parts; (3) no number of nonconscious parts could combine to produce a conscious whole; (4) the properties of a whole are determined by the properties of its parts. Eliminative physicalists reject Claim (1). Panpsychists and panprotopsychists reject Claim (2), as do substance dualists, idealists, and nonorganismic dual-attribute theorists albeit for different reasons. Many emergentists, epiphenomenalists, physicalists, and neutral monists reject Claim (3), hylomorphists reject Claim (4), and some mind-body pessimists claim that the problem is entirely insoluble..

Problem of Free Will and Determinism

A philosophical problem that can be understood in terms of the following claims. either determinism is true, or determinism is false. if determinism is true, then there is no free will. if determinism is false, then there is no free will. There is moral responsibility only if there is free will. There is a moral responsibility. Compatibilist theories try to solve the problem by rejecting claims 2 or 4. Libertarian theories try to solve the problem by rejecting claim 3, and hard determinist and hard incompatibilist theories try to solve the problem by rejecting claim 5.

Theory model of psychological discourse.

A popular account of psychological language suggested by Wilfrid Sellars and Hilary Putnam among others, but defended principally by Paul and Patricia Churchland. According to the theory model, psychological discourse is or is like a scientific theory that postulates hypothetical entities (mental states) whose relations to one another are supposed to explain observable human behavior. Critics of the theory model include exponents of the pattern expression theory of psychological language such as hylomorphists.

Functionalism

A popular theory that claims mental states are functional states that correlate inputs to a system with outputs from it and with other internal states. Although functionalism was originally inspired by the Turing test and the ideas of Alan Turing, it was first formulated by Hilary Putnam. Unlike many other theories in mind-body debates, functionalism does not take a stand on what exists. It does not say, for instance, that everything is physical, or that some things are nonphysical. Functionalism is officially neutral with regard to ontological issues, and simply offers a characterization of psychological language. Psychological discourse, it says, is abstract discourse that ignores the physical or other details of a system and focuses simply on how the system correlates inputs with outputs. Psychological discourse, in other words, is analogous to geometrical discourse which ignores the physical details of something (what it is made of, say) and focuses simply on its spatial properties. According to functionalists, therefore, mental properties are abstract higher-orderproperties that are realized by concrete lower-order things. Functionalists argue that their theory provides the most obvious explanation for multiple realizability. Critics deny this and argue that functionalism has problems with the Chinese room argument, the embodied mind objection, and the liberalism objection. Teleological functionalists attempt to deal with this third problem by placing restrictions on the kinds of systems that can realize mental states. Although functionalism is compatible with substance dualism, idealism, neutral monism, and dual-attribute theory, it is frequently endorsed in conjunction with physicalism. The resulting view is realization physicalism.

Problem of other minds

A problem posed by the following claims: (1) we often know what other people think and how they feel; (2) what other people think and how they feel belong to a private, subjective domain; (3) if what other people think and how they feel belong to a private, subjective domain, then we cannot know what other people think and how they feel as often as we suppose. Eliminative physicalists, some substance dualists, and some dual-attribute theorists reject Claim (1). Hylomorphists and behaviorists reject Claim (2) in favor of a direct access thesis, and many philosophers reject Claim (3) in favor some inferential access thesis.

Psychophysical identity theory

A reductive physicalist theory that claims that mental states will be identified with states of the nervous system through empirical investigation - a process of theoretical identification.

Behaviorism (in psychology)

A term used in psychology to designate the claim that psychologists should concern themselves only with observable phenomena. This is often called 'methodological behaviorism'. It has more and less radical interpretations. Radical behaviorists such as B. F. Skinner claimed that psychologists should not even postulate inner mechanisms to explain overt stimulus-response patterns.

Hylomorphism

A theory that claims structure or organization is a real and irreducible ontological and explanatory principle. Things are composed of more than simply fundamental physical materials or particles, they are composed of those materials structured or organized in various ways. Those structures are responsible for distinguishing one kind of thing from another, and for explaining why those things operate as they do. Hylomorphism represented the dominant approach to understanding human psychological capacities prior to the Scientific Revolution. A hylomorphic theory of mind applies the general principles of hylomorphism to mind-body problems

mind-body pessimism

A theory that denies the possibility of solving mind-body problems.

Turing Test

A thought experiment proposed by the British mathematician Alan Turing. A human judge interacts using a text-only apparatus with a human, on the one hand, and with a machine on the other. If the judge cannot tell which interlocutor is the human and which the machine, the machine is said to pass the Turing test. Turing suggested that intelligence consists in nothing but correlating inputs with outputs in the right kinds of ways, and hence a machine that passes the Turing test should count as an intelligent being. This idea inspired functionalism.

Teleological functionalism

A type of functionalist theory that places restrictions on the kinds of systems that can realize mental states. To realize mental states, teleological functionalists say, a system must have parts that serve a purpose in the system; they must have a function in a teleological sense, a sense that differs from the notion of function employed by classic functionalist theories. By placing restrictions on realization, teleological functionalists look to respond to the liberalism objection to functionalism.

Type versus token physicalism

A way of drawing the distinction between reductive and nonreductive physicalism based on the type-token distinction. Nonreductive physicalism is called 'token physicalism' because it claims that every token, that is every particular individual or event, is a physical token even though not every type is a physical type. The types of individuals, properties, or events postulated by the special sciences, for instance, are not physical types. Reductive physicalism, on the other hand, is often called 'type physicalism' because it claims that the categories or types postulated by the special sciences correspond directly to the categories or types postulated by physics. Every token is thus a physical token, but in addition every type is a physical type. Because the type -token distinction can be applied to a broad range of ontological categories, the distinction between type and token physicalism is not fully informative unless we know what the types and tokens in question are, and for that reason other formulations of physicalist theories are preferable.

Chisholm, Roderick (1916-1999)

American philosopher best known in philosophy of mind for defending a nonorganismic dual-attribute theory by appeal to mereological essentialism, for defending an agent-causal theory of free will, and for introducing Anglo-American philosophers to Franz Brentano's notion of intentionality.

Problem of mental causation

Actions have physical causes, events in the nervous system. They also have mental causes - beliefs and desires, for instance. Understanding how the mental causes and the physical causes of actions are related poses a philosophical problem: (1) actions have mental causes; (2) actions have physical causes; (3) mental causes and physical causes are distinct; (4) an action does not have more than one cause. Claims (1)-(3) imply that any given action has more than one cause, but Claim (4) rules this out. Eliminative physicalists and epiphenomenalists reject Claim (1). Psychophysical identity theorists reject Claim (3). Emergentists, nonreductive physicalists, and substance dualists reject either Claim (2) or Claim (4), and hylomorphists argue by appeal to causal pluralism that the problem equivocates on the term 'cause', and once the equivocation is resolved, claims (1)-(4) are no longer inconsistent. Kim's exclusion argument appeals to the problem to disprove nonreductive physicalism and emergentism.

Sensorimotor contingencies

Also called 'sensorimotor expectations': lawlike relations among sensation, movement, and the environment. I know implicitly, for instance, that if I were to move my head around the object in front of me it would present me with a different visual profile. Exponents of sensorimotor theories of consciousness claim that the qualitative aspects of our experience are constituted in part by our implicit knowledge of sensorimotor contingencies.

Multilevel worldview

Also called a 'multilayered worldview': a picture of the universe according to which reality consists of a number of different levels or layers. The levels are often taken to correspond to branches of science, with the lowest level corresponding to the objects, properties, and events postulated by fundamental physics, followed by the objects, properties, and events postulated by atomic physics, chemistry, biology, psychology, and social sciences such as economics. Lower-level objects, properties, and events are taken to compose higher-level objects, properties, and events. Fundamental physical particles are taken to compose atoms, for instance, which compose molecules, which compose organic tissues, which compose organisms, which compose social systems. Different multilevel worldviews understand interlevel relations in different ways: some take higher-level sciences to be reducible to lower-level ones; others deny this. Some take higher-level properties to emerge from interactions among lower-level systems; others take higher-level properties to be realized by lower-level interactions. Yet others take higher-level phenomena to be embodied in lower-level subactivities and subsystems. Levels can be defined globally or locally. A global view of levels claims that the same hierarchy of levels exists throughout the natural world. A local view of levels denies that there is a single levels-hierarchy existing throughout the natural world; rather, there are different kinds of levels corresponding to different kinds of things.

Burge, Tyler (1946-)

American philosopher best known for defending externalism.

Block, Ned (1942-)

American philosopher best known for his work on consciousness and for cataloging the problems with functionalism including the liberalism objection.

Dretske, Fred (1932-)

American philosopher best known in philosophy of mind for defending a sophisticated covariation theory of mental representation. According to Dretske, mental representation consists in what an internal component has the function of indicating within a broader system. The function of a system's sensory organs or subsystems is to supply it with information about the environment, something it does by having internal states that covary with states of the environment.

Davidson, Donald (1917-2003)

American philosopher best known in philosophy of mind for his work on action theory and anomalous monism. Davidson argued against followers of Ludwig Wittgenstein that psychological explanation was a species of causal explanation. Davidson's argument for anomalous monism develops several ideas of his mentor, the philosopher W. V. O. Quine.

Dennett, Daniel (1942-)

American philosopher known in philosophy of mind for attacking qualia and defending compatibilism and instrumentalism. Dennett's more considered view is not instrumentalist, however, but is best described as a form of nonreductive physicalism that emphasizes the practical advantages of psychological explanation: we use psychological discourse because it is more efficient for explaining and predicting human behavior than physics.

Pattern expression theory of psychological language

An account of psychological language that was suggested by Ludwig Wittgenstein, and that is endorsed by exponents of a hylomorphic theory of mind. Psychological language is not like a theory that postulates hypothetical entities, as the theory model of psychological discourse claims. Rather, psychological language is a form of social behavior that uses symbols to express directly observable patterns of social and environmental interaction.

Consciousness

An ambiguous term used in at least two senses in philosophy of mind. In one sense it refers to certain publicly observable aspects of someone's behavior: whether someone is responsive to verbal commands or painful stimuli, for instance. This is the sense used in ordinary discourse when we say that someone who is asleep or drugged is not conscious. The notion of consciousness that has taken center stage in mind-body debates, however, is often called 'phenomenal consciousness'. It refers to the allegedly private, qualitative aspects of experience - qualia. According to one standard account of phenomenal consciousness, qualia are nonrelational and unanalyzable. It is possible to analyze the brain mechanisms involved in, for instance, seeing a ripe tomato, but exponents of this account of consciousness claim that the qualitative dimension of seeing a ripe tomato cannot be analyzed into the activities of and relations among discrete mechanical components. Other accounts of phenomenal consciousness reject the idea that qualia are nonrelational and unanalyzable. These include representational theories of consciousness, higher-order theories of consciousness, and sensorimotor theories of consciousness.

Knowledge argument

An anti-physicalist argument advanced by Frank Jackson. If physicalism is true, then all facts are physical facts. But not all facts are physical facts, says the argument, since it is possible for someone to know all the physical facts without knowing all the facts. Mary, for instance, has complete physical knowledge. She knows all the physical facts, but she has never before experienced color. When she experiences color for the first time, she learns something new; she gains knowledge of a fact she didn't know before. Since she knew all the physical facts, she must have learned a nonphysical fact. Hence, not all facts are physical facts; physicalism must be false. Criticisms of the argument include the ability hypothesis, and the claim that Mary knows the same old facts under new representations.

Empirical versus conceptual essentialism

An argument advanced by Descartes to support the substance dualistic claim that persons can exist without bodies. Our only essential property is thinking, says the argument. If that is our only essential property, however, the only property we need to exist, then we do not need physical properties to exist. But if we do not need physical properties to exist, then we do not need bodies to exist. Hence, persons can exist without bodies. The argument is implicitly committed to conceivability-possibility principles and conceptual essentialism.

Essential property argument

An argument advanced by Descartes to support the substance dualistic claim that persons can exist without bodies. Our only essential property is thinking, says the argument. If that is our only essential property, however, the only property we need to exist, then we do not need physical properties to exist. But if we do not need physical properties to exist, then we do not need bodies to exist. Hence, persons can exist without bodies.The argument is implicitly committed to conceivability-possibility principles and conceptual essentialism.

Consequence argument

An argument against compatibilism. We are free, says the argument, only if what we do is up to us. If determinism is true, however, what we do is not up to us, for if determinism is true, then our actions are necessary consequences of the laws of nature together with events in the past - including events that occurred before we were born. But the laws of nature and events in the past are not up to us. If these things are not up to us, however, then our actions are not up to us since they are the necessary consequences of things that are not up to us. So if determinism is true, what we do is not to us. But if what we do is not up to us, then we are not free. Consequently, if determinism is true, we are not free. Compatibilism must therefore be false. The consequence argument remains controversial.

Embodied mind objection

An argument against functionalism that claims that human psychological capacities cannot be defined abstractly in the way functionalists suppose. Mental states are instead essentially embodied in the kinds of substructures or subsystems humans possess. Contemporary exponents of embodied mind objections in cognitive science argue that explanations of cognitive capacities that assume embodiment are superior to functionalist-inspired explanations that do not.

Conceivability argument

An argument that supports the substance dualist's claim that persons can exist without bodies. If it is conceivable that persons can exist without bodies, says the argument, then persons can exist without bodies, and it is in fact conceivable that persons can exist without bodies. Therefore, persons can exist without bodies.

Multiple-realizability argument

An argument that was taken to show the falsity of the psychophysical identity theory and to support anti-reductivism. The argument has three premises. The first is called the multiple-realizability thesis: (1) Mental states are multiply realizable; that is, it is possible for a given type of mental state to be realized in more than one type of physical state. Pain, for instance, might be realized by states of a human brain, the states of a Martian gamma organ, or the states of complex robotic circuitry. (2) If mental states are multiply realizable, then they are not identical to physical states. (3) If mental states are not identical to physical states, then psychological discourse is not reducible to physical theory. The multiple-realizability thesis is defended by appeal to conceivability-possibility principles and by appeal to work in biology, neuroscience, and artificial intelligence research. Reductive physicalists can respond to the argument in several ways, so it remains controversial. It has nevertheless been very influential, and together with functionalism it inspired nonreductive physicalism.

Chinese room argument

An objection to functionalism and Strong AI originally formulated by the philosopher John Searle. If functionalism is true, then it is impossible for two systems to be functionally identical and mentally distinct. Yet it is possible for two systems to be functionally identical and mentally distinct. A person could learn to correlate Chinese language inputs with Chinese language outputs by following instructions on a sophisticated chart, and thereby come to correlate inputs with outputs in the same way a native speaker does. The person and the native speaker would thus be functionally identical, yet they would be mentally distinct since the person, unlike the native speaker, would not understand Chinese. The person operates the same way as a computer, so if the person does not understand Chinese merely by correlating inputs with outputs the way a speaker does, the machine doesn't understand Chinese either.

Democritus (b. 460 BCE)

Ancient Greek philosopher credited with having been the first to believe in the existence of atoms. Democritus suggests an early version of reductive physicalism.

Kim's trilemma

Anti-reductivism implies that mental properties are not physical properties. Physicalism implies, however, that all genuine properties - all causal properties - are physical properties. Consequently, if mental properties are not physical properties as anti-reductivism claims, then it looks like mental properties cannot be genuine properties, contrary to anti-eliminativism. Suppose, however, that we accept anti-eliminativism: mental properties, we insist, are genuine properties. Physicalism implies that all genuine properties are physical. Consequently, if mental properties are genuine properties as anti-eliminativism claims, then it looks like mental properties must be physical properties, contrary to anti-reductivism. Suppose, finally, that we accept anti-reductivism and also anti-eliminativism. The properties postulated by psychological discourse are not the same as those postulated by physics, we say, but they are genuine properties nonetheless. In that case, it looks like not all genuine properties are physical, contrary to physicalism. It is thus impossible to endorse physicalism, anti-eliminativism, and anti-reductivism as realization physicalists want.

Qualia-based arguments

Arguments that appeal to the existence of qualia in an effort to show that physicalism and similar theories are false. According to the arguments, it is possible for two systems, A and B, to be physically indistinguishable and yet differ in their phenomenal states or qualia: Perhaps A and B experience different qualia (the possibility of inverted qualia) or perhaps A has qualia while B altogether lacks them (the possibility of absent qualia: B would be a qualia zombie). Either way, if physicalism is true, then absent and inverted qualia should be impossible. If they are possible, therefore, physicalism must be false.

Armstrong, David M.

Australian philosopher best known in philosophy of mind for defending a version of the psychophysical identity theory and a higher-order theory of consciousness.

Eddington, Arthur Stanley (1882-1944)

British astronomer and physicist. Eddington was one of the first scientists to try to confirm Einstein's general relativity theory experimentally. He is known in philosophy for having proposed a philosophical problem concerning two tables: the table described by physics and the table described by common sense.

Berkeley, George (1685-1753)

British philosopher best known in philosophy of mind for having defended a reductivist form of ontological idealism.

Churchland, Paul M. (1942-) and Patricia S. (1943-)

Canadian-American philosophers best known for defending eliminative physicalism.

Conceivability-possibility principles

Claims with the form 'If it is conceivable that p, then it is possible that p'. Conceivability-possibility principles are used as premises in many arguments in philosophy of mind and in philosophy generally. Philosophers will often appeal to conceivability-possibility principles without explicitly stating them - a practice that conceals their contentious nature.

Hierarchical theories

Compatibilist theories that analyze free will in terms of the conformity of lower-order desires to higher-order desires. first-order desires are desires for ordinary things while second-order desires are desires for other desires. Critics argue that hierarchical theories fail to capture our intuitions about what constitutes moral responsibility.

Capacity-based theories of free will and moral responsibility

Compatibilist theories that analyze free will in terms of the exercise of certain capacities such as the capacity for rational self-governance. Critics argue that capacity-based theories fail to capture our intuitions about what constitutes moral responsibility.

Reactive attitude theories

Compatibilist theories that ground moral responsibility in ordinary social practices involving reactive attitudes such as gratitude and resentment. The term 'reactive attitudes' is due to the philosopher P. F. Strawson. Critics argue that reactive attitude theories fail to capture our intuitions about what constitutes moral responsibility.

Dual-attribute theory (DAT)

Dual-attribute theories are committed to the conjunction of property dualism and psychophysical coincidence;coincidence; they claim, in other words, that mental and physical properties are distinct, and that the same individual can have properties of both sorts. Forms of substance dualism, by contrast, endorse property dualism but reject psychophysical coincidence. DATs are sometimes referred to simply as forms of property dualism, but this label is misleading because substance dualism is committed to property dualism as well. DATs are distinguished from each other by two factors: their claims about the things that have both mental and physical properties, and their claims about how mental and physical properties are related. Organismic DATs claim that the things having both mental and physical properties are organisms. These theories are often committed to animalism. Nonorganismic DATs deny that the things having both mental and physical properties are organisms. The most popular forms of DAT are emergentism and epiphenomenalism. Both claim that mental properties are generated or produced by physical interactions. DATs are sometimes conflated with forms of nonreductive physicalism.

Bridge principles

Empirically supported premises that connect the vocabularies of theories that do not share the same stock of predicates and terms. Bridge principles are necessary for intertheoretic reduction if the reduced theory's vocabulary has predicates and terms that the vocabulary of the reducing theory lacks. An example of a bridge principle would be 'heat = mean molecular kinetic energy' which was necessary for the reduction of thermodynamics to statistical mechanics.

Agent-causal theories

Forms of libertarianism that claim that actions are produced not by antecedent events, but directly by agents by means of a special kind of causal relation, agent causation. Critics argue that exponents of agent causation have failed to prove that this type of causal relation really exists.

Arnauld, Antoine (1612-1694)

French philosopher best known in philosophy of mind as the author of the Fourth set of objections to Descartes' Meditations.

Brentano, Franz (1838-1917)

German philosopher best known in philosophy of mind for reintroducing the notion of intentionality into modern philosophy. He was the teacher of Edmund Husserl, and influenced the work of Roderick Chisholm.

Higher- and lower-order properties

Higher-order properties are properties whose definitions quantify over other properties. Realization physicalists claim that mental properties are higher-order properties. Pain, for instance, is defined as the property of having some physical property that correlates certain inputs with certain outputs. The physical properties are in this case lower-order relative to pain, and particular instances of pain are said to be realized by particular instances of physical properties. Higher- and lower-order properties should not be confused with higher- and lower-level properties since levels need not correspond to orders of abstraction. They should also not be confused with higher- and lower-order desires as these are understood in discussions of hierarchical theories of free will and moral responsibility. Finally, higher-order properties should not be confused with the notions of higher-order thought and higher-order perception as they are understood in connection with higher-order theories of consciousness.

Higher-order theories of consciousness

Higher-order theories of consciousness claim that conscious states are internal states of a system that are monitored by other internal states of that system. I am conscious of seeing red, for instance, when I have an internal sensory state that registers the presence of redness in the environment, and another internal state that registers the presence of the internal sensory state. There are at least two kinds of higher-order theories of consciousness. Higher-order perception theories claim that the internal monitoring states are like inner perceptions of sensory states; higherorder thought theories claim that the internal monitoring states are like thoughts about sensory states. Higher-order theories of consciousness are very similar to representational theories of consciousness. Physicalists have looked to both to provide them with resources for responding to qualia-based arguments against their view.

Liberalism objection to functionalism

If functionalism is true, then almost anything can realize mental states, even systems that are intuitively bizarre such as a giant "brain" that is composed of all the people in China. It is nevertheless absurd to suppose that such systems could really have mental states; therefore, functionalism must be false.

Logical Behaviorism

It claims that psychological expressions are abbreviations for longer descriptions of actual and potential behavior, where paradigmatic behavior consists in bodily movements and utterances. Logical behaviorism is motivated by the reductive physicalist attempt to show that mental phenomena are physical phenomena. Unlike the psychophysical identity theory which tries to show this a posteriori through scientific investigation, logical behaviorism tries to show this a priori through conceptual analysis. It implies that every psychological expression can be analyzed into an equivalent physical description of actual and potential behavior. Logical behaviorism faced numerous problems, and was largely abandoned with the demise of positivism in the early 1950s.

Mental

Mental phenomena are defined by psychological discourse. Mental properties and events are those expressed by psychological predicates and descriptions. There are broadly speaking two conceptions of mental phenomena: a private versus a public conception of mental phenomena.

Delgado, Jose (1915-)

Neurosurgeon who pioneered techniques of neural manipulation.

Mind-body Problems

Philosophical problems arise when we try to understand how mental phenomena are related to physical phenomena. Examples include the problem of other minds, the problem of mental causation, and the problem of psychophysical emergence. Sometimes the expression the mind-body problem, with the definite article is used to refer to the range of problems that concern the nature of mental phenomena and their relation to physical phenomena.

Physical

Physical phenomena are defined by physics. Physical objects, properties, and events in the strictest sense are those postulated by physics.

Descartes, René (1596-1650)

Prominent French philosopher whose ideas are largely responsible for philosophy of mind as we have understood it since the seventeenth century. Descartes is best known for having defended substance dualism by appeal to a modal argument, and for his attempt to defend interactionism. The exact nature of Descartes' substance dualism is nevertheless a matter of dispute. Some interpreters compare his philosophy of mind to that of Thomas Aquinas, but others insist that his philosophy marks a radical break with his medieval predecessors. Descartes' famous works on mind and body include Meditations on First Philosophy and Principles of Philosophy.

Aquinas, Thomas (1224-1275)

Prominent medieval philosopher who is best known in philosophy of mind as a defender of a medieval Aristotelian theory of the soul. The exact nature of his views is a matter of considerable dispute. Some interpreters claim that he endorsed a form of substance dualism. Others maintain that he defended a version of hylomorphism, and yet others that he defended a version of the soul view of persons.

Representational theories of consciousness

Representational theories claim that phenomenal consciousness can be understood in terms of mental representation. They deny that qualia are private nonrelational phenomena, and claim instead that the qualitative features we experience are features of objects we experience themselves - features that we represent internally with our sensory organs. Redness we experience when looking at a tomato, for instance, is a property of the tomato itself which is represented with an internal state of the nervous system that registers the presence of that property in the environment. Physicalists have appealed to representational theories of consciousness in an effort to respond to qualia-based arguments against their view.

Special sciences

Sciences other than fundamental physics such as chemistry, biology, psychology, and social sciences such as economics. Fundamental physics is supposed to be the one general science whose laws apply everywhere without exception. By contrast, the laws of the special sciences are limited to specific domains - living things in the case of biology, for instance, or mental things in the case of psychology. The term 'special science' is also used to refer to conceptual frameworks that are not strictly speaking scientific such as ordinary psychological discourse.

Elisabeth of Bohemia (1618-1680)

The Princess Elisabeth is best known as a student of Descartes who posed the problem of interaction.

Idealism

The claim is that everything is mental. The term is used to refer to either conceptual idealism or ontological idealism. Conceptual idealism claims that our experiences of the world depend in part on concepts or structures supplied by our minds. Kant's transcendental idealism is an example of conceptual idealism. Ontological idealism is like an inverse image of physicalism. Its most prominent defender was the British philosopher George Berkeley, ontological idealists have followed Berkley in being reductivist about physical discourse: our talk of mind independent objects, they say can be reduced to talk of our experiences. This type of view is often called phenomenalism

Anti-eliminativism

The claim that eliminativism is false. There are mental states; psychological discourse is at least to some extent accurate.

Determinism

The claim that for any given state of the universe at a time, there is exactly one possible resultant state that comes about because of antecedent conditions in conjunction with the laws of nature. Soft determinism combines determinism with compatibilism, and hard determinism combines determinism with incompatibilism.

Anti-reductivism

The claim that mental properties are not identical to physical properties, or that psychological discourse is not reducible to physical theory.

Causal pluralism

The claim that there are many different kinds of causes and many different kinds of causal relations. Hylomorphists appeal to causal pluralism to solve the problem of mental causation.

Animalism

The claim that we are identical to animals.

Phyicalism

The claims that everything is physical. Types of physicalism include eliminative physicalism, reductive physicalism, and non-reductive physicalism. Critics argue against it by appeal to Hemphill's dilemma, the knowledge argument, and qualia-based arguments.

Intentionality

The feature at least some mental states have of being about, or of, or for something. A fear, for instance, is always fear of something, a belief is always a belief about something, a desire is always a desire for something. The notion of intentionality played an important role in medieval philosophy, but was ignored in the modern period until it was reintroduced in the nineteenth century by the German philosopher Franz Brentano, and made its way into Anglo-American philosophy due in part to Roderick Chisholm. John Searle has done much to clarify the notion. Philosophers also talk about intentionality in terms of mental representation: mental states such as beliefs are said to represent the world. Intentionality is also discussed in terms of propositional attitudes. A belief that 2 + 2 = 4 is an attitude of acceptance directed toward the proposition '2 + 2 = 4'. In addition, that proposition is said to be the content of the intentional state or mental representation. Physicalists have often been concerned with giving accounts of intentionality that are compatible with their view. They typically understand intentionality in terms of mental representation, and then try to account for mental representation in terms of relations found throughout the physical universe. Covariation theories of mental representation, for instance, try to account for mental representation in terms of causation, something that physicalists claim can be understood exhaustively in terms of physics.

Aristotle (384-322 BCE)

The greatest philosopher of antiquity, best known in philosophy of mind as an early defender of hylomorphism who endorsed causal pluralism and advanced an early version of the embodied mind objection against one of his contemporaries.

Supervenience

The idea that entities (properties, events, descriptions) cannot differ in one respect without differing in another. To say that A - properties supervene on B - properties, for instance, is to say that two things, x and y, cannot differ from each other in A-respects without differing from each other in B-respects. If x and y have all the same B-properties, then they must have all the same A-properties; B-twins, in other words, must be A-twins. There are different kinds of supervenience relations: weak, global, and strong, for instance. A-properties weakly supervene on B-properties exactly if for any individuals x and y in world w, if x and y are physical twins in w, they must also be mental twins in w. A-properties globally supervene on B - properties, on the other hand, exactly if worlds with indistinguishable distributions of B-properties over individuals would also have indistinguishable distributions of A-properties over individuals. And A-properties strongly supervene on B-properties exactly if it is impossible for x in world w1 and y in world w2 to differ from each other in respect of their A-properties without differing from each other in respect of their B-properties. During the 1980s and 1990s many philosophers believed that some type of supervenience relation would provide the basis for a workable form of nonreductive physicalism. Their optimism has since cooled in light of criticisms advanced by philosophers like Jaegwon Kim.

Subjectivity versus objectivity

The idea that mental states are subjective is the idea that they are accessible in principle to only one person - the person whose mental states or experiences they are. Objective phenomena, by contrast, are accessible in principle to more than one person. Bodily behavior, for instance, is supposed to be objective. In philosophy of mind, the subjective-objective distinction is closely related to the internal-external or inner-outer distinction. Some views claim that our mental states comprise inner, subjective domains that are accessible only to the people whose experiences they are while our bodily behavior belongs to an outer, objective domain that is accessible to other people. This picture gives rise to the inferential access thesis. The notion of subjectivity is also related to the idea that each of us occupies a unique point of view. Thomas Nagel claims that science is an effort to achieve an objective outlook - a view from nowhere - that is free from the particularities of any one subjective point of view.

Direct access thesis

The idea that other people's mental states are directly observable; we know what mental states other people have by directly perceiving them not by making inferences from bodily behavior. Hylomorphists and logical behaviorists both endorse versions of the direct access thesis. It is opposed to the inferential access thesis.

First-person authority

The idea that the knowledge each of us has of his or her own mental states is in some sense privileged. Each of us can be wrong about what mental states other people have in a way that we cannot be wrong about what mental states we ourselves have. First-person authority is not the same as first-person infallibility, the idea that it is impossible for us to be wrong about what we believe, or desire, or feel. Nor is first-p erson authority the same as first-person incorrigibility, the idea that it is impossible for other people to correct us about what we think, desire, or feel.

Properties

The ontological correlates of predicates. Properties are expressed by predicates. Mental properties are expressed by mental predicates. Physical properties are expressed by physical predicates.

Transitivity of identity

The principle that if x = y, and y = z, then x = z. The transitivity of identity is central to the model of theoretical identification endorsed by David Lewis and David Armstrong.

Theoretical identification

The process of identifying entities postulated by one theory with entities postulated by another theory through scientific investigation. The notion of theoretical identification factors centrally in the psychophysical identity theory. There are at least two models of theoretical identification. J. J. C. Smart proposed that theoretical identification was a result of Ockham's razor. David Lewis and David Armstrong argued that it was instead an implication of the transitivity of identity: if pain, say, is by definition the state caused by burns, and we discover empirically that brain state B is the state caused by burns, then pain must be identical to brain state B.

Instrumentalism

The view that psychological discourse does not aim at expressing real properties, as realist theories of psychological language claim. Rather, psychological discourse is merely a tool or instrument for predicting human behavior whose use carries with it no significant ontological implications.

Disjunctivism

The view that there need not be an inner experiential element that is common to both accurate and inaccurate experiences. There need not be an inner state - a visual experience, say - that is common to both perception and hallucination, for instance.

Constitutionalism

The view that we are constituted by animals. Constitution is supposed to be a relation between two things that share all the same parts but that nevertheless differ in their properties. A statue, for instance, is said to be constituted by a lump of clay. The statue and the lump share all the same parts, but they are different things according to constitutionalists because they have different properties. The lump, for instance, but not the statue can survive being squashed. Content See Intentionality.

Covariation theories of mental representational

Theories that try to account for mental representation in terms of causal covariation relations between states of the environment and states of experiencing subjects. To have an internal representation of redness, for instance, is to have an internal component that is activated if and only if something in the environment is red. Simple covariation theories claim that causal covariation relations of this sort are all mental representation consists in, but these theories have difficulty explaining what determines the content of mental representations - what the representations are of or about (see Intentionality). Sophisticated covariation theories like Fred Dretske's and Jerry Fodor's look to address these difficulties.

Events

There are at least three theories of events that philosophers of mind appeal to when stating their views. The property-exemplification theory defended by Jaegwon Kim, Alvin Goldman, and Jonathan Bennett claims that events are individuals having properties or standing in relations at times. Donald Davidson defends a different theory of events according to which events are unrepeatable particulars individuated by their causes and effects. Other philosophers endorse bundle theories of events according to which events are bundles of properties.

Rationality

To describe people's behavior in terms of their beliefs, desires, and other intentional mental states is to classify that behavior as something that is explainable by appeal to reasons. It is important to distinguish nonrational behavior from irrational behavior. Nonrational behavior is behavior that is not explainable by appeal to reasons. The behavior of a rock, for instance, is nonrational. Irrational behavior, on the other hand, is behavior that is explainable by appeal to reasons, but that fails to satisfy certain criteria for rational evaluation. If I act contrary to what I believe is in my best interests, then I act irrationally but not nonrationally.

Hylomorphic Theory of Mind

While some structures in nature are just spatial arrangements among a things parts, state exponents of a hylomorphic theory of mind, the characteristic ways that living things interact with each other and their environment are structured phenomena as well. These patterns of social and environmental interaction include mental states. A hylomorphic theory is mind rejects the idea that mental states are internal States. Mental states might incorporate internal states such as states of the nervous system, but they are not identical to those internal states since they also involved social and environmental factors. A hylomorphic theory of mind is easily confused with logical behaviorism. Both theories reject the idea that mental states are internal states, but they differ in at least three respects: hylomorphism rejects physicalism, behaviorists do not, hylomorphism has a broader conception of what counts as behavior than behaviorists do, and hylomorphists have a different understanding of psychological language. A hylomorphic theory of mind is committed to externalism, disjunctivism, to the pattern expression theory of psychological language, to the direct access thesis, and to the embodiment thesis. Exponents of the theory are also sympathetic to sensorimotor theories of consciousness.

Sensorimotor theories of consciousness

consciousness Sensorimotor theories claim that the qualitative features of experience can be given an account in terms of patterns of sensorimotor interaction with the environment. What it's like to see red, for instance, is constituted by the range of ways we respond to and interact with red objects using our senses and motor abilities. These forms of interaction involve implicit knowledge of sensorimotor contingencies. Because sensorimotor theories of consciousness take conscious experiences to be patterns of environmental interaction, they mesh neatly with a hylomorphic theory of mind. Physicalists, however, can also appeal to them in an effort to respond to qualia-based arguments against their view.

Hempel's dilemma

dilemma An argument against physicalism suggested by the philosopher of science Carl Hempel. Physicalism says that everything is the way physics says it is. But physics must be defined either relative to a preliminary stage of scientific theorizing, or relative to the final, ideal stage of scientific theorizing. If it is defined in the former way, then physicalism is false since preliminary physical theories are false. If it is defined in the latter way, then physics lacks content since we do not yet know what the final, ideal physical theory will say.

Ockham's razor

razor A methodological principle named after the fourteenth-century philosopher William of Ockham (1287-1347). It says that when constructing theories entities are not to be multiplied beyond necessity. Given a choice between two theories that are otherwise indistinguishable, Ockham's razor dictates that we should prefer the theory with the simpler ontology, the one that posits fewer basic entities. Ockham's razor is a premise in J. J. C. Smart' s argument for the psychophysical identity theory.