Notes on the Philosophy of Mind Including notes on Descartes, Ryle, Smart, Putnam and Searle
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s	Three Main Parts Philosophy of psychology Philosophical psychology Metaphysics of the mind Philosophy of Psychology Psychology is the study of mental activity. The philosophy of psychology is part of the philosophy of science. The philosophy of psychology analyzes the goals, terminology and methods of psychology. E.g., philosophical critiques of Freudian psychology, behaviourism, and computer-analogy psychology Philosophical Psychology Analyzes our common language of the mental. Seeks to provide clear distinctions between concepts involved in our everyday psychology. E.g., the nature of perception, memory, voluntary behaviour Metaphysics of the Mind Tries to understand the underlying nature of mental phenomena. Four important questions. What is the relationship between the mind and the brain? How is it that some of our mental states are directed at the world? How do they become meaningful? What is the origin of consciousness? How do mental states interact with the physical world? What is the relationship between the mind and the brain? We know that the mind and the brain are closely related. Events that effect the brain effect the mind. E.g., the ingestion of hallucinogenic drugs, physical injury to the brain. Is the mind nothing but brain activity or is there something more? Is the mind made up of something other than brain matter? Is the mind a different sort of thing from a brain altogether? How is it that some of our mental states are directed at the world? Much of our mental states are about the external world. How do they become meaningful? How does the mind represent combinations of thing in the world into mental states? E.g., How can you understand the collection of letters that make up this sentence? What is the origin of consciousness? Why do things feel a certain way? Why should it be that we have some sensation of what it is like to experience something. E.g., Experiencing the colour blue. How do mental states interact with the physical world? If the mind behaves according to rationality, how does it interact with a world of brute causality? A bullet does not leave a gun because it ought to leave the gun. How can it be that the person that fires the gun can do so because of his mental states? How can thought be a part of nature? Dualism The most popular theory of the mind. But not with philosophers. Most non-philosophers hold to this view Most religious believers hold to this view It is probably the oldest and most widespread theory of mind There are two separate and distinct substances that make up a human being: mind and body. In religious terms, the mind is sometimes equated with the soul. Dualism is suggested by our day-to-day experiences. It is quite common to distinguish between “my body” and “my self”, and our bodies may become injured or ill whilst our minds are active and alert. Our mental experience is also private, reinforcing the feeling that it is somehow separate. Dualism is part of Western tradition. Views that spring from folklore, native belief and religion can all influence our views of our self. This is sometimes done consciously – as in the religious doctrine of immortality – or subtly, through language and the way in which we refer to ourselves. Back to top. Descartes and Substance Dualism René Descartes is usually pointed to as the primary exponent of substance dualism First certain knowledge claimed in the Meditations: I exist. (Particularly, cogito ergo sum.) Descartes first establishes that he exists as a thinking thing. He still has reasons to doubt that his body exists. This begins Descartes' division of mind and body. Descartes concluded that the mind was a completely distinct substance from matter. Matter is easily described: it is measurable, has dimensions, can be touched and seen, sometimes smelt and tasted, divided, destroyed and altered. Mind, however, can almost be defined as the opposite of this. It is invisible, without dimensions, immaterial, unchanging, indivisible and without limit. Descartes’ definition is of the mind seems to have almost no positive qualities. In defining mind and matter in this way Descartes is also fulfilling a religious agenda. Mind so defined can be equated with the soul, which in turn can be proven to be distinct from the body and immortal. Descartes suppressed one of his early works when he saw how the Catholic Church treated the astronomer Galileo and is at pains in the preface of the Meditations to gain the favour of the doctors of theology in Paris. Descartes was a very religious man with a sincere faith. Interactionism The problem with Descartes' definition of mind and body is that he seems to be describing two mutually exclusive substances. If, in every respect, matter differs from mind, how are the two meant to interact? Descartes needs to explain this because, unlike other theories which we will look at later, there is meant to be a causal interaction between the two substances – in other words, mind influences matter and vice versa. This is called interactionism. However, the difficulty here is how a material thing – our body – can be influenced by a non-material thing – our mind. By Descartes’ definition mind is immaterial, having no dimension, mass, etc. But then how can something without any physical effects influence a physical thing? According to current scientific thinking, physical objects are only affected by physical forces. Even if we think in terms of atoms, molecules or particles, we are still talking about things with dimension and mass – however small. In this sense, the material world is a closed circuit of cause and effect. Descartes’ response was to suggest that the two substances meet in a part of the brain called the pineal gland. His reasons for choosing this seem to have been that the gland in central (unlike the other parts of the brain which are bilateral – mirrored on each side) and that it does not occur in animals. This latter fact was understood by Descartes as relating to the presence of a soul in humans and not in animals, whom he considered mere machines. However, modern research has also found a similar gland in mammals and lower vertebrates. Occasionalism Following Descartes’ death, some philosophers – such as Nicholas Malebranche (1638 – 1715) – recognised this problem and tried to address it whilst still holding to the dualist view. Malebranche’s suggestion was that neither body nor mind were causally related, but were in fact connected by divine interaction. So, whenever we wish to lift an arm, for instance, God must intervene to cause the body to obey (similarly, whenever the body feels pain, God must cause that sensation to occur in the mind). Occasionalism has long been considered a rather odd viewpoint that seems unable to exist outside of a theological perspective. Even within it, however, there are problems: if God is responsible for all seeming causal interactions, is he also responsible for evil deeds? This would make him the unwitting agent in murders, crimes, etc. Spinoza and Double-Aspect Theory A more radical slant on the mind-body problem was presented by the Jewish-Dutch philosopher Baruch Spinoza (1632 – 1677) who argued that there were not really two substances, but two attributes of the same substance. Thus reality was therefore a case of two perspectives on the same thing: physical matter as perceived through the senses and mental stuff as experienced with the mind. The problem here is that it leaves the nature of this common substance undefined. If matter and mind are only attributes of it, what then is it? Another problem is that the theory requires that mind and body correspond – and yet, is this the case? Things seem to happen in the body that the mind is not aware of, nor can we really say whether there is always a corresponding mental process for every physical one. Leibniz and psychophysical parallelism Yet another solution to the problem was presented by the German philosopher Gottfried Wilhelm Leibniz (1646 – 1716) who rejected interactionism, occasionalism and double-aspect theory in favour of the view that mind and body exist in pre-established harmony. From this viewpoint, no interaction or causation is necessary because, like two clocks that keep the same time, the behaviour of the two substances has been synchronised. However, pre-established harmony seems to deny the possibility of freewill, though this was a general problem with Leibniz's philosophy. The problem is this: if substances are co-ordinated in pre-established harmony, how can this be compatible with free choice? Leibniz's answer is to point out that, regardless of the actual choice made, another choice is possible. So, although it might seem to be predetermined that you are reading this, it was logically possible that you might have done something else. This is not really a very convincing argument, for to accept that we have a choice we would have to consider it a contingent truth that something happens (i.e. it could have been otherwise). However, in organising the pre-established harmony God has chosen the best of all possible worlds. He has done this, obviously, because he is good - necessarily good, that is. So, doesn't this then mean that God must choose this world and everything is predetermined? Epiphenomenalism Whilst Cartesian dualism argues that there is a two-way interaction between mental and physical substances, not all forms of dualism agree. Epiphenomenalism argues that mental events are caused by - or are a by-product of - physical events, but that the interaction is one-way: mental events cannot affect physical ones. The analogy often used is that of the smoke that comes from a factory which is a by-product of its running, but does not actually affect its running. One of the curious side effects of this theory is that it implies that decision making is not a mental event. Apart from flying in the face of most common sense attitudes, this consequence throws up a further problem: how are decisions made? Is decision making a bodily process? If so, what difference is there between epiphenomenalism and certain forms of materialism? Epiphenomenalism is often confused with materialism but this is in fact a misunderstanding. The reason for this is the way in which the theory classes mental events as secondary, leading to the view that physical events are primary. While this may be true, what most people miss is the fact that mental events are said to be caused by physical events. This being so, mental events cannot be identical with events, just as smoke cannot be identical with the fire which causes it. Types of Monism Monism, because it describes a belief in one substance, can be used in two distinct ways: To describe the view that only matter, or the physical body, exist. To describe the view that only mind, or spirit, exist. The first option is called "materialism" or "physicalism"; the second option is called "idealism" (which you may remember from our discussion of Berkeley in TOK). While few people accept the idealist viewpoint, materialism is quite a widely held view. The main task for the materialist, however, is to show that consciousness and the mind can be accounted for in terms of properties of matter and the functioning of a physical substance: the brain. Back to top. Gilbert Ryle, The Concept of Mind: Descartes' Myth Descartes made a category mistake in declring the mind as a separate substance. One makes a category mistake when one thinks that things belong to the same category or group of things when they do not. (For example, one might think that the University of Western Ontario is a particular a building on campus when in fact it's a different sort of thing entirely.) Descartes believed that because the language of the mind was different from the language of the body, the two must be of separate substances. For Ryle, the mind is a higher order function of the body. The mind is something that the body does, it is not something that some different thing does. Physicalism and the Computer The general idea of the programmable calculating machine was developed by Charles Babbage and Ada Lovelace in the 1800s. In the twentieth century, the actual construction of programmable calculating machines was developed by Alan Turing. At the time, businesses and academic institutions made use of people, called computers, to do routine calculation. In 1936, Alan Turing wrote a paper called, "On computable numbers, with an application to the Entscheidungsproblem." This paper was about the nature of calculation, and sought to solve some mathematical problems. Some mathematical problems, this paper showed, could not be solved. In particular, the Entscheidungsproblem, or decision problem, about whether or not one could construct a logical method that would determine whether or not a logical theory could be proven or not. In part of this 1936 paper, Turing described in some detail simple calculating machines, which we now call Turing machines. Turing machines are pretty much a mechanical box with a strip of tape running through them. A Turing machine can only do a limited amount of things: It can change its internal state (which determines what it will do next) It can move its attention one square to the right or the left. It can read the tape running through it. It can write a "0" or a "1" onto the tape. Working in binary (representing all numbers through a sequence of ones and zeros), there can be a Turing machine for every calculation. Turing proved that some specific Turing Machine could do any one specific calculation that we can do. The complete list of the possible internal states of the machine, along with the step that each state leads to, is called the Machine Table (at least by Putnam). One can represent the entire machine by the Machine Table. Turing also proved that one could imagine a universal Turing machine that could act as any other Turing machine. (When people talk about Turing Machines, they often mean universal Turing machines.) Everything that a Turing machine does, it does according to rules. Feed the universal Turing machine the rules of a specific Turing machine, and it will then act like that Turing machine. Our modern computers are almost universal Turing machines. With enough memory and time, any computer can perform the same calculations as any other computer. With enough time and a long enough tape, a universal Turing machine could perform any calculation that a modern computer can perform. A probabilistic Turing machine is one that is not guaranteed to go from one specific internal state to only one internal state. A probabilistic Turing machine could pass on to a number of other internal states, each one with a different probability. There is nothing that the probabilistic Turing machine can do that a Turing machine cannot do. As the machine operates, from moment to moment, the odds determine which regular Turing machine the probabilistic Turing machine turns out to be. Back to top. J.J.C. Smart, Sensations and Brain Processes Smart doesn't necessarily want to show that minds are computers, but he does want to show that mental operations could be physical operations. Smart wants to present a scientifically plausible account of how it can be that there can be ideas somehow present in physical matter. (If the mind is the brain, then it's physical and ideas must be in that physical matter.) Smart focusses on the idea of sensations. The content of our other ideas (and at least part of their physicality) can be found in our behaviour. The sensations we feel are another matter. Smart adresses eight objections to the idea that sensations are brain processes. Objection One: We can talk about mental processes, but we have no knolwedge of the brian. Reply: Our ignorance has no effect on the truth. Objection Two: We could be very wrong in our science of the brain. Reply: Just because science does change does not mean that there is no fact of the matter about our brains. Objection Three: There are mental properties that aren't possibly physical properties. Reply: The limit of physical properties is what we can investigate. If we can find a way to investigate mental properties through the brain, then mental properties are manifestly physical. Objection Four: An after-image in our mind is not located in physical space, yet our brain is locatred in physical space. Reply: The description of a mental process using mental language may not be correct. We might be able to locate the process if we knew more about the brain. Objection Five: One can describe the brain using physical descriptions like speed, but not sensations. Reply: This inability might be due merely to our current lack of knowledge of the brain. Objection Six: Sensations are private, brain processes are potentially public. Reply: Again, the limits of our physical investigation are the limits of what is public. We could one day be able to investigate the sensations of others. Objection Seven: I can imagine myself as being turned to stone or without a body and still be thinking. Reply: This should be treated as a hypothesis. As such, it is open to investigation. Objection Eight: How could there ever be descriptions of sensations? We can only describe what is common to us, and sensations are particularly private. (Beetle-in-the-box objection) Reply: Perhaps investigation into the brain will be able to identify particular brain responses as sensations and we will be able to determine something common through this. Back to top. Hillary Putnam, The Nature of Mental States Part I of Putnam's article is a review of the argument Smart presents against the a priori rejection of physicalism. Putnam is not committed to physicalism, however. In Part II, Putnam lays out his hypothesis that "being in pain is a functional state of the organism." Putnam uses the idea of the computer to represent mental events and actions as functions. Any mental event can be represented by the function that it plays in the transition of one state of an organism to another state. All organisms capable of feeling pain are Probabilistic Automata. Every organism capable of feeling pain possesses at least one Description of a certain kind (i.e., being capable of feeling pain is possessing an appropriate kind of Functional Organization). No organism capable of feeling pain possesses a decomposition into parts which separately possess Descriptions of the kind referred to in (2). For every Description of the kind referred to in (2), there exists a subset of sensory inputs such that an organism is in pain when and only when some of its sensory inputs are in that subset. Probabilistic Automata: a machine that acts as a probabilistic Turing machine, but has physical action as its output. Description: The description of the possible states of a system and the transition probabilities from state to state (i.e., what are the odds of moving from one state to another.) Why is functionalism better than brain-state physicalism? It allows us to consider (as we do) that creatures with different brains than our own may feel pain. Observed behaviour arising gives us more reason to believe that organisms share the same functional organization than it gives us reason to believe that they have the same internal physical structure Functionalism is not Behaviourism The function of pain is not always shown in behaviour. One can refrain from acting on pain if one has other interests. The state of being in pain is part of the overall state of the organism, which is where behaviour is seen. Question: Why, or why not, should we consider this theory a theory of physicalism? Back to top. John R. Searle Searle is a critic of the artificial intelligence program. Searle is not advocating dualism. He believes that there is something special about the brain that creates consciousness. It is consistent with his view to believe that it is possible for other, natural systems to become conscious. Three Theses of the Strong Artificial Intelligence Program The mind is a program. Neurophysiology is irrelevant to the study of the mind. The Turing Test is the criteria of the mental. Theses one and two can be found in the reading of Putnam's article on functionalism. Putnam requires of mental activities that they fulfil certain functions. The mind requires a certain functional organization and indeed may be this organization. Any physical structure that implements the proper function can be part of a being that has mind. The Turing Test was developed by Alan Turing in 1950 as a hypothetical means to test for consciousness in a machine. [Computing Machinery and Intelligence (Mind, Vol. 59, No. 236, pp. 433-460)] He called the test, "the imitation game." For Turing, the question of whether or not a machine can think is equivalent to whether or not a machine can successfully imitate a person. The new form of the problem can be described in terms of a game which we call the 'imitation game." It is played with three people, a man (A), a woman (B), and an interrogator (C) who may be of either sex. The interrogator stays in a room apart front the other two. The object of the game for the interrogator is to determine which of the other two is the man and which is the woman. He knows them by labels X and Y, and at the end of the game he says either "X is A and Y is B" or "X is B and Y is A." The interrogator is allowed to put questions to A and B thus: C: Will X please tell me the length of his or her hair? Now suppose X is actually A, then A must answer. It is A's object in the game to try and cause C to make the wrong identification. His answer might therefore be: "My hair is shingled, and the longest strands are about nine inches long." In order that tones of voice may not help the interrogator the answers should be written, or better still, typewritten. The ideal arrangement is to have a teleprinter communicating between the two rooms. Alternatively the question and answers can be repeated by an intermediary. The object of the game for the third player (B) is to help the interrogator. The best strategy for her is probably to give truthful answers. She can add such things as "I am the woman, don't listen to him!" to her answers, but it will avail nothing as the man can make similar remarks. We now ask the question, "What will happen when a machine takes the part of A in this game?" Will the interrogator decide wrongly as often when the game is played like this as he does when the game is played between a man and a woman? These questions replace our original, "Can machines think?" When talking about the Turing Test today what is generally understood is the following: The interrogator is connected to one person and one machine via a terminal, therefore can't see her counterparts. Her task is to find out which of the two candidates is the machine, and which is the human only by asking them questions. If the machine can "fool" the interrogator, it is intelligent. Thesis Two: The irrelevance of neurophysiology: The Strong AI theorist proposes that the actual chemical processes of the body are irrelevant to the mind. If this is the case, then the actual chemical processes of the body should be irrelevant to feelings of thirst in the mind. So if the Strong AI theorist is right, a computer could feel thirsty without a body. Is it right to call the computer thirsty? Searle's analogy: No one seems to worry that a simulation of a fire will burn anything down. No one should be worried that the computer is thirsty. Imagine that the actual "computer" that is running the program of a thirsty mind is made up of beer cans arranged on a grid and hooked up through an elaborate system of levers powered by windmills. Is this beer can computer thirsty? Can any Rube Goldberg machine that we make to run a mind program actually have a consciousness? Thesis Three: The Turing Test: The Chinese Room Argument People slip sentences written in Chinese on bits of paper through a slot on the door. The person inside the room slips replies in Chinese out through the same slot. The Chinese Room contains within it a number of ledgers and tables. These ledgers and tables enable one to look at Chinese symbols from a sentence and cross-reference them in order to construct a sentence in response. One only needs to look at the symbols and compare them to drawings in the books and tables. One can pick cards with pre-written symbols out of appropriate drawers in order to produce the correct response. The person inside the room does not need to understand Chinese in order to reply to the cards that come in through the slot in a way that mimics understanding. The Chinese Room, as a whole, can pass the Turing Test. Back to top.	s
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