Computational theory of mind
Encyclopedia
In philosophy
, the computational theory of mind is the view that the human mind
is an information processing system and that thinking is a form of computing
. The theory was proposed in its modern form by Hilary Putnam
in 1961 and developed by Jerry Fodor
in the 60s and 70s. This view is common in modern cognitive psychology
and is presumed by theorists of evolutionary psychology
.
The computational theory of mind is a philosophical concept that the mind functions as a computer or symbol manipulator. The theory is that the mind computes input from the natural world to create outputs in the form of further mental or physical states. A computation
is the process of taking input and following a step by step algorithm
to get a specific output. The computational theory of mind claims that there are certain aspects of the mind that follow step by step processes to compute representations of the world.
The computational theory of mind requires representation because 'input' into a computation comes in the form of symbols or representations of other objects. A computer cannot compute an actual object, it must interpret and represent the object in some form and then compute the representation. The computational theory of mind is related to the representational theory of mind in that they both require that mental states are representations. However the two theories differ in that the representational theory claims that all mental states are representations while the computational theory leaves open that certain mental states, such as pain or
depression, may not be representational and therefore may not be suitable for a computational treatment. These non-representational mental states are known as qualia
. The computational theory of mind is also related to the language of thought
. The language of thought theory allows the mind to process more complex representations with the help of semantics. (See below in semantics of mental states).
'Computer' is not meant to mean a modern day electronic computer. Rather a computer is a symbol manipulator that follows step by step functions to compute input and form output. Alan Turing
describes this type of computer in his concept of a Turing Machine
.
of language are the features of words and sentences that relate to their meaning, the semantics of mental states are those meanings of representations, the definitions of the ‘words’ of the language of thought
. If these basic mental states can have a particular meaning just as words in a language do, then this means that more complex mental states (thoughts) can be created, even if they have never been encountered before. Just as new sentences that are read can be understood even if they have never been encountered before, as long as the basic components are understood, and it is syntactically correct. For example: “I have eaten plum pudding every day of this fortnight.” While it's doubtful many have seen this particular configuration of words, nonetheless most readers should be able to glean an understanding of this sentence because it is syntactically correct and the constituent parts are understood.
John Searle
has offered a thought experiment known as the Chinese Room
that demonstrates this problem. Imagine that there is a man in a room with no way of communicating to anyone or anything outside of the room except for a piece of paper that is passed under the door. With the paper, he is to use a series of provided books to “answer” what is on the paper. The symbols are all in Chinese, and all the man knows is where to look in the books, which then tell him what to write in response. It just so happens that this generates a conversation that the Chinese man outside of the room can actually understand, but can our man in the room really be said to understand it? This is essentially what the computational theory of mind presents us with; a model in which the mind simply decodes symbols and outputs more symbols. It is argued that perhaps this is not real learning or thinking at all. However, it can be argued in response to this that it is the man and the paper together that understand Chinese, albeit in a rudimentary way due to the rudimentary nature of the system; as opposed to if the man learned Chinese, which would create a sophisticated system of communicating Chinese.
Searle has further raised questions about what exactly constitutes a computation:
Putnam has similarly claimed that "every ordinary open system realizes every abstract finite automaton." Computationalists have responded by aiming to develop criteria describing what exactly counts as an implementation.
Additionally, Roger Penrose
has proposed the idea that the human mind does not use a knowably sound calculation procedure to understand and discover mathematical intricacies. This would mean that a normal Turing complete computer would not be able to ascertain certain mathematical truths that human minds can.
Philosophy of mind
Philosophy of mind is a branch of philosophy that studies the nature of the mind, mental events, mental functions, mental properties, consciousness and their relationship to the physical body, particularly the brain. The mind-body problem, i.e...
, the computational theory of mind is the view that the human mind
Mind
The concept of mind is understood in many different ways by many different traditions, ranging from panpsychism and animism to traditional and organized religious views, as well as secular and materialist philosophies. Most agree that minds are constituted by conscious experience and intelligent...
is an information processing system and that thinking is a form of computing
Computing
Computing is usually defined as the activity of using and improving computer hardware and software. It is the computer-specific part of information technology...
. The theory was proposed in its modern form by Hilary Putnam
Hilary Putnam
Hilary Whitehall Putnam is an American philosopher, mathematician and computer scientist, who has been a central figure in analytic philosophy since the 1960s, especially in philosophy of mind, philosophy of language, philosophy of mathematics, and philosophy of science...
in 1961 and developed by Jerry Fodor
Jerry Fodor
Jerry Alan Fodor is an American philosopher and cognitive scientist. He holds the position of State of New Jersey Professor of Philosophy at Rutgers University and is the author of many works in the fields of philosophy of mind and cognitive science, in which he has laid the groundwork for the...
in the 60s and 70s. This view is common in modern cognitive psychology
Cognitive psychology
Cognitive psychology is a subdiscipline of psychology exploring internal mental processes.It is the study of how people perceive, remember, think, speak, and solve problems.Cognitive psychology differs from previous psychological approaches in two key ways....
and is presumed by theorists of evolutionary psychology
Evolutionary psychology
Evolutionary psychology is an approach in the social and natural sciences that examines psychological traits such as memory, perception, and language from a modern evolutionary perspective. It seeks to identify which human psychological traits are evolved adaptations, that is, the functional...
.
The computational theory of mind is a philosophical concept that the mind functions as a computer or symbol manipulator. The theory is that the mind computes input from the natural world to create outputs in the form of further mental or physical states. A computation
Computation
Computation is defined as any type of calculation. Also defined as use of computer technology in Information processing.Computation is a process following a well-defined model understood and expressed in an algorithm, protocol, network topology, etc...
is the process of taking input and following a step by step algorithm
Algorithm
In mathematics and computer science, an algorithm is an effective method expressed as a finite list of well-defined instructions for calculating a function. Algorithms are used for calculation, data processing, and automated reasoning...
to get a specific output. The computational theory of mind claims that there are certain aspects of the mind that follow step by step processes to compute representations of the world.
The computational theory of mind requires representation because 'input' into a computation comes in the form of symbols or representations of other objects. A computer cannot compute an actual object, it must interpret and represent the object in some form and then compute the representation. The computational theory of mind is related to the representational theory of mind in that they both require that mental states are representations. However the two theories differ in that the representational theory claims that all mental states are representations while the computational theory leaves open that certain mental states, such as pain or
depression, may not be representational and therefore may not be suitable for a computational treatment. These non-representational mental states are known as qualia
Qualia
Qualia , singular "quale" , from a Latin word meaning for "what sort" or "what kind," is a term used in philosophy to refer to subjective conscious experiences as 'raw feels'. Examples of qualia are the pain of a headache, the taste of wine, the experience of taking a recreational drug, or the...
. The computational theory of mind is also related to the language of thought
Language of thought
In philosophy of mind, the language of thought hypothesis put forward by American philosopher Jerry Fodor describes thoughts as represented in a "language" that allows complex thoughts to be built up by combining simpler thoughts in various ways...
. The language of thought theory allows the mind to process more complex representations with the help of semantics. (See below in semantics of mental states).
"Computer metaphor"
Computational theory of mind is not the same as the computer metaphor, according to which the mind literally works like a computer. Computational theory just uses some of the same principles as those found in digital computing.'Computer' is not meant to mean a modern day electronic computer. Rather a computer is a symbol manipulator that follows step by step functions to compute input and form output. Alan Turing
Alan Turing
Alan Mathison Turing, OBE, FRS , was an English mathematician, logician, cryptanalyst, and computer scientist. He was highly influential in the development of computer science, providing a formalisation of the concepts of "algorithm" and "computation" with the Turing machine, which played a...
describes this type of computer in his concept of a Turing Machine
Turing machine
A Turing machine is a theoretical device that manipulates symbols on a strip of tape according to a table of rules. Despite its simplicity, a Turing machine can be adapted to simulate the logic of any computer algorithm, and is particularly useful in explaining the functions of a CPU inside a...
.
Causal picture of thoughts
At the heart of the Computational Theory of Mind is the idea that thoughts are a form of computation, and a computation is by definition a systematic set of laws for the relations among representations. Meaning that a mental state represents something if and only if there is some causal correlation between the mental state and that particular thing. An example would be seeing dark clouds and thinking “clouds mean rain”, there is a correlation between the thought of the clouds and rain, as the clouds causing rain. This is known as Natural Meaning. Conversely, there is another side to the causality of thoughts and that is the non-natural representation of thoughts. An example would be seeing a red traffic light and thinking “red means stop”, there is nothing about the color red that indicates it represents stopping, and thus is just a convention that has been invented, similar to languages and their abilities to form representations.Semantics of mental states
The computational theory of mind states that the mind functions as a symbolic operator, and that mental representations are symbolic representations; just as the semanticsSemantics
Semantics is the study of meaning. It focuses on the relation between signifiers, such as words, phrases, signs and symbols, and what they stand for, their denotata....
of language are the features of words and sentences that relate to their meaning, the semantics of mental states are those meanings of representations, the definitions of the ‘words’ of the language of thought
Language of thought
In philosophy of mind, the language of thought hypothesis put forward by American philosopher Jerry Fodor describes thoughts as represented in a "language" that allows complex thoughts to be built up by combining simpler thoughts in various ways...
. If these basic mental states can have a particular meaning just as words in a language do, then this means that more complex mental states (thoughts) can be created, even if they have never been encountered before. Just as new sentences that are read can be understood even if they have never been encountered before, as long as the basic components are understood, and it is syntactically correct. For example: “I have eaten plum pudding every day of this fortnight.” While it's doubtful many have seen this particular configuration of words, nonetheless most readers should be able to glean an understanding of this sentence because it is syntactically correct and the constituent parts are understood.
Criticism
There are arguments against the Computational Theory of Mind. Some of the most compelling encompass the physical realm of a computational process. Gallistel writes in Learning and Representation about some of the implications of a truly computational system of the mind. Essentially Gallistel is concerned with the limits of thermodynamics within the circuits of the brain. With the high volume of information, and the low level of lost material necessary, we have to ask where the energy comes from and how the heat would be dissipated.John Searle
John Searle
John Rogers Searle is an American philosopher and currently the Slusser Professor of Philosophy at the University of California, Berkeley.-Biography:...
has offered a thought experiment known as the Chinese Room
Chinese room
The Chinese room is a thought experiment by John Searle, which first appeared in his paper "Minds, Brains, and Programs", published in Behavioral and Brain Sciences in 1980...
that demonstrates this problem. Imagine that there is a man in a room with no way of communicating to anyone or anything outside of the room except for a piece of paper that is passed under the door. With the paper, he is to use a series of provided books to “answer” what is on the paper. The symbols are all in Chinese, and all the man knows is where to look in the books, which then tell him what to write in response. It just so happens that this generates a conversation that the Chinese man outside of the room can actually understand, but can our man in the room really be said to understand it? This is essentially what the computational theory of mind presents us with; a model in which the mind simply decodes symbols and outputs more symbols. It is argued that perhaps this is not real learning or thinking at all. However, it can be argued in response to this that it is the man and the paper together that understand Chinese, albeit in a rudimentary way due to the rudimentary nature of the system; as opposed to if the man learned Chinese, which would create a sophisticated system of communicating Chinese.
Searle has further raised questions about what exactly constitutes a computation:
the wall behind my back is right now implementing the Wordstar program, because there is some pattern of molecule movements that is isomorphic with the formal structure of Wordstar. But if the wall is implementing Wordstar, if it is a big enough wall it is implementing any program, including any program implemented in the brain.
Putnam has similarly claimed that "every ordinary open system realizes every abstract finite automaton." Computationalists have responded by aiming to develop criteria describing what exactly counts as an implementation.
Additionally, Roger Penrose
Roger Penrose
Sir Roger Penrose OM FRS is an English mathematical physicist and Emeritus Rouse Ball Professor of Mathematics at the Mathematical Institute, University of Oxford and Emeritus Fellow of Wadham College...
has proposed the idea that the human mind does not use a knowably sound calculation procedure to understand and discover mathematical intricacies. This would mean that a normal Turing complete computer would not be able to ascertain certain mathematical truths that human minds can.
Prominent scholars
- Daniel DennettDaniel DennettDaniel Clement Dennett is an American philosopher, writer and cognitive scientist whose research centers on the philosophy of mind, philosophy of science and philosophy of biology, particularly as those fields relate to evolutionary biology and cognitive science. He is currently the Co-director of...
proposed the Multiple Drafts ModelMultiple Drafts ModelDaniel Dennett's multiple drafts model of consciousness is a physicalist theory of consciousness based upon cognitivism, which views the mind in terms of information processing. The theory is described in depth in his book, Consciousness Explained, published in 1991...
, in which consciousness seems linear but is actually blurry and gappy, distributed over space and time in the brain. Consciousness is the computation, there is no extra step or "Cartesian TheaterCartesian theaterThe Cartesian theater is a derisive term coined by philosopher Daniel Dennett to pointedly refer to a defining aspect of what he calls Cartesian materialism, which he considers to be the often unacknowledged remnants of Cartesian dualism in modern materialistic theories of the mind.Descartes...
" in which you become conscious of the computation. - Jerry FodorJerry FodorJerry Alan Fodor is an American philosopher and cognitive scientist. He holds the position of State of New Jersey Professor of Philosophy at Rutgers University and is the author of many works in the fields of philosophy of mind and cognitive science, in which he has laid the groundwork for the...
argues that mental states, such as beliefs and desires, are relations between individuals and mental representations. He maintains that these representations can only be correctly explained in terms of a language of thought (LOT) in the mind. Further, this language of thought itself is codified in the brain, not just a useful explanatory tool. Fodor adheres to a species of functionalism, maintaining that thinking and other mental processes consist primarily of computations operating on the syntax of the representations that make up the language of thought. - David Marr proposed that cognitive processes have three levels of description: the computational level (which describes that computational problem (i.e., input/output mapping) computed by the cognitive process); the algorithmic level (which presents the algorithm used for computing the problem postulated at the computational level); and the implementational level (which describes the physical implementation of the algorithm postulated at the algorithmic level in biological matter, e.g. the brain). (Marr 1981)
- Ulric NeisserUlric NeisserUlric Neisser is an American psychologist and member of the National Academy of Sciences. He is a faculty member at Cornell University. In 1995, he headed an American Psychological Association task force that reviewed The Bell Curve and related controversies in the study of intelligence. The task...
coined the term 'cognitive psychology' in his book published in 1967 (Cognitive Psychology), wherein Neisser characterizes people as dynamic information-processing systems whose mental operations might be described in computational terms. - Steven PinkerSteven PinkerSteven Arthur Pinker is a Canadian-American experimental psychologist, cognitive scientist, linguist and popular science author...
described a "language instinct," an evolved, built-in capacity to learn speech (if not writing). - Hilary PutnamHilary PutnamHilary Whitehall Putnam is an American philosopher, mathematician and computer scientist, who has been a central figure in analytic philosophy since the 1960s, especially in philosophy of mind, philosophy of language, philosophy of mathematics, and philosophy of science...
proposed functionalism (philosophy of mind)Functionalism (philosophy of mind)Functionalism is a theory of the mind in contemporary philosophy, developed largely as an alternative to both the identity theory of mind and behaviourism. Its core idea is that mental states are constituted solely by their functional role — that is, they are causal relations to other mental...
to describe consciousness, asserting that it is the computation that equates to consciousness, regardless of whether the computation is operating in a brain, in a computer, or in a "brain in a vat." - Bruno Marchal, professor at the Free University of BrusselsFree University of BrusselsThe Free University of Brussels was a university in Brussels, Belgium. In 1969, it split into the Université Libre de Bruxelles and the Dutch-speaking Vrije Universiteit Brussel....
, claims in a Ph.D thesis (University of Lille, France, 1998, Calculabilité, physique et cognition) that physical supervenience is not compatible with computational theory, using arguments like Universal Dovetailer Argument or Movie Graph Argument. - Georges ReyGeorges ReyGeorges Rey is a professor of philosophy at the University of Maryland.His book Contemporary Philosophy of Mind takes the reader into the middle of contemporary debates in philosophy of mind...
, professor at the University of MarylandUniversity of MarylandWhen the term "University of Maryland" is used without any qualification, it generally refers to the University of Maryland, College Park.University of Maryland may refer to the following:...
, builds on Jerry Fodor's representational theory of mind to produce his own version of a Computational/Representational Theory of Thought.
Alternative Theories
- Classical associationismAssociationismAssociationism in philosophy refers to the idea that mental processes operate by the association of one state with its successor states.The idea is first recorded in Plato and Aristotle, especially with regard to the succession of memories....
- ConnectionismConnectionismConnectionism is a set of approaches in the fields of artificial intelligence, cognitive psychology, cognitive science, neuroscience and philosophy of mind, that models mental or behavioral phenomena as the emergent processes of interconnected networks of simple units...
- Situated cognitionSituated cognitionSituated cognition poses that knowing is inseparable from doing by arguing that all knowledge is situated in activity bound to social, cultural and physical contexts....
- Memory-prediction frameworkMemory-prediction frameworkThe memory-prediction framework is a theory of brain function that was created by Jeff Hawkins and described in his 2004 book On Intelligence...
See also
- CognitivismCognitivism (psychology)In psychology, cognitivism is a theoretical framework for understanding the mind that came into usage in the 1950s. The movement was a response to behaviorism, which cognitivists said neglected to explain cognition...
- ConstructivismConstructivismConstructivism may refer to:* Constructivist epistemology, the philosophical view* Constructivism in international relations* Constructivism , a philosophical view on mathematical proofs and existence of mathematical objects...
- Philosophy of mindPhilosophy of mindPhilosophy of mind is a branch of philosophy that studies the nature of the mind, mental events, mental functions, mental properties, consciousness and their relationship to the physical body, particularly the brain. The mind-body problem, i.e...
- FunctionalismFunctionalism (philosophy of mind)Functionalism is a theory of the mind in contemporary philosophy, developed largely as an alternative to both the identity theory of mind and behaviourism. Its core idea is that mental states are constituted solely by their functional role — that is, they are causal relations to other mental...
External links
- A Computational Foundation for the Study of Cognition by David ChalmersDavid ChalmersDavid John Chalmers is an Australian philosopher specializing in the area of philosophy of mind and philosophy of language, whose recent work concerns verbal disputes. He is Professor of Philosophy and Director of the Centre for Consciousness at the Australian National University...
- Computationalism: The Very Idea, an overview of computationalism by David Davenport.
- The Stanford Encyclopedia of Philosophy's entry on the computational theory
- The Cognitive Process Consciousness model of the Mind
- Fodor, The Mind Doesn't Work that Way
- Collection of links to online papers
- Bruno Marchal argues that physical supervenience is not compatible with computational theory (French)