Mind–Body Dualism Research Paper

Mind body dualism, in either form, has raised two major philosophical questions:

(a) ‘How is it possible for immaterial mind and material body to interact, as it seems they obviously do, be they substances or properties?’

(b) ‘Where does the core of personal identity lie, in the material body or the immaterial mind, in the material or the mental aspects of a person?’

The monistic accounts offered by materialists and idealists purport to be solutions to some of the problems inherent in either version of the dualist account.

2. The Ontological Version of Mind Body Dualism

The origin of the thesis that mind and body are different substances is usually credited to Descartes. He came to this view in the course of reflecting on whether there was any belief that could not be doubted. The program of analysis that led him to his ontological version of mind body dualism is set out in his Sixth Meditation.

To begin with, I will go back over all the things which I previously took to be perceived by the senses, and reckoned to be true; and I will go over my reasons for thinking this. Next, I will set out my reasons for subsequently calling these things into doubt. And finally I will consider what I should now believe about them (Descartes 1641 p. 51).

He convinced himself that his mental states were better known to him than his material surroundings, including his own body, so the indubitable truth must be mental. The first step in recovering knowledge of himself and the world must be to find an undubitable premise or premises from which the main characteristics of the world and of myself as a center of consciousness, that is as a thinking thing, can be deduced. Descartes’ method in philosophy and in the sciences was based on his faith in the power of logic to ensure that, step by step, the mind passes from truths to truths. ‘… there is nothing so far removed from us as to be beyond our reach, or so hidden that we cannot discover it, provided only we abstain from accepting the false for the true, and always preserve in our thoughts the order necessary for the deduction of one truth from another’ (Descartes 1644 p. 16). But what could serve as a premise for the deduction of secure knowledge about myself and from that to secure knowledge about the natural world? It must be both thinkable and indubitable. Borrowing from earlier sources Descartes gives us the most famous philosophical argument in history, ‘cogito ergo sum.’ It is supposed to undermine the possibility of universal doubt. If someone is doubting that he or she is thinking, then, since doubting is a species of thinking, that person is thinking. So the existence of thinking is indubitable.

However, Descartes draws a much stronger conclusion. His argument, so often quoted and parodied, is supposed to prove that a thinking thing exists, namely a mind, soul, or ego, that is truly Descartes (Descartes 1641 p. 19). The argument begins with ‘I am thinking therefore I exist’ (Descartes 1644 p. 194). Though meant to highlight the indubitability of the existence of the thinker as thinking thing, it led straight to the thesis that the mind and the body of a person are two radically different substances. The attributes of a thinking substance, a mind, are immaterial. It is indivisible and, being indivisible, must be immortal. A mind has no properties in common with a material, divisible, spatially, and temporally locatable body. But the body supplies the mind with sensations that are not at the whim of the person, while the mind makes the body move in ways that the person intends. So mind and body must interact. How could such interactions occur when Descartes’ analysis leaves each with properties that could have no causal relations with one another? The person or self, being an entity, can be the target of acts of reference, just as material entities like Mt. Blanc are denoted by proper names. While the name ‘Descartes’ refers to the whole ensemble, body and mind, the pronoun ‘I’ seems to refer to the ego, the really real Descartes, the immaterial entity that is the mind. It also serves as the source of personal identity.

There is one obvious objection to the move from the indubitability of the existence of acts of thinking to the conclusion that there must be immaterial thinking things. At most we know thinkings must exist, not that there must a substance, an entity that is doing the thinking. The circularity of the argument is clearer in French than in Latin.

Je pense

donc

Je suis.

Far from this argument proving the existence of a Cartesian ego, since ‘je,’ appears in the conclusion of the argument, and in the premise, the argument is circular. The only valid argument that the doubting paradox supports is this:

Doubting exists

therefore

Thinking exists.

One might well reject the idea that personal identity is rooted in an immaterial entity while still holding that thinking, feeling, and willing are immaterial processes. The mind body problem appears on the one hand as the problem of how two quite different kinds of entities could interact, and on the other as the problem of assigning priority between bodily continuity and individuality as the basis of personal identity, or on continuity of mind, as given in consciousness through the power of memory.

3. The Discursive Version of Mind Body Dualism

An alternative way of making sense of the radical differences that seem to mark off mental states of persons from material states of their bodies has been to propose that there are two irreducible sets of predicates, one used for describing the body and its states and the other for describing the mental life of conscious beings. Some body predicates can be used to describe any material thing, while others can be used only of other organisms. Mental predicates, for the most part, can be used only of human beings, though some can also be used of animals, such as ‘alert’ of a dog. But there is just one entity to which these descriptions are to be applied. For some philosophers this entity is the human body as organism (Searle 1992). For others it is the person, the basic particular of human life (Strawson 1956).

We recollect that when Descartes realized that the mental and material properties of human beings were very different he was tempted into thinking that, therefore, a person must be constituted of two different substances each with its proper set of attributes. By an ingenious analysis of the material conditions that are involved in the basic criteria of personal identity, Strawson was able to show that the concept of a person is logically prior to ‘having a body’ and ‘having a mind.’ The Cartesian distinctions among predicates do not lead inexorably to the theory of two substances, the material body and the immaterial mind, the alleged thinking thing. The basic particulars of the human world are persons. A person must be embodied in order for it to be possible for that person to be reidentified as one and the same person who one had met before. This involves M or material predicates. But a person is also the subject of ascriptions of P or person predicates, which involve consciousness. According to Strawson a person can ascribe consciousness to him or herself only if that person can ascribe such states to others. There must be logically adequate criteria for ascriptions of P predicates. So we are left with two sets of predicates for describing people, both of which are necessary and neither of which is sufficient to encompass the whole of human life.

In Searle’s version of this approach, the dualism is founded on the intentionality of mental states, a feature not shared by material states of the organism. Intentionality is the property that a significant sign has of pointing beyond itself, of meaning something, whether or not there is anything in the world to which it corresponds. Mental states are just those states of the organism that do point beyond themselves. But thought is not anything other than an aspect of the biology of human organisms, just as is digestion. This view is far from new. Cabanis remarked that thought is a secretion of the brain, just as bile is of the liver.

4. Supervenience

A third suggestion (Kim 1998) is based on the idea that there could be no thought without a material system, such as a brain and nervous system, while there are many material systems that are not conscious or cognitively active. It has been said that the mental supervenes on the material without being reducible to it. This proposal does not seem to touch the deep question of how the states of the material system and the mental states that supervene upon it are related.

5. Criticisms

Ontological dualism has been under attack from its beginnings in the seventeenth century. There have been two lines of criticism, materialist and idealist. If either of these monisms could be defended it would put paid to the discursive dualism based on two radically distinct sets of predicates. Both criticisms are based on arguments designed to show that there really is only one kind of property that human beings possess. It follows that there would be only one kind of predicate which could be ascribed to a human being.

5.1 How Materialists get Rid of the Mind

Traditionally materialists have tried to solve the interactional aspect of the mind body problem by eliminating the mental side of the incommensurable pair. If it could be shown that the phenomenon that people had taken to be mental and so radically different from the material attributes of a human being were really material after all, then there would be no ontological problem about the possibility of a causal relation between the states of the sensory systems and sensations and perceptions. One material state can cause another. If it could be shown that all mental concepts could be replaced by material concepts, without loss of content, the mind body problem would evaporate in a more fundamental way. The logical subject to which the reformed vocabulary would be predicated would be denoted by an expression for a material thing, the body.

How could one show that a vocabulary was so radically defective that it ought to be replaced by a different set of words? In the 1950s several philosophers of science, notably Hanson (1958), who coined the phrase ‘the theory-ladeness of observations,’ reviving a thesis popular at the beginning of the nineteenth century, pointed out that there is no sharp division between words used in theories and words used to describe phenomena, since the latter incorporate theoretical concepts. For example when the word ‘heat’ is used in the description of a calorific phenomenon, people literate in science understand it as having a complex meaning, partly phenomenological, partly in terms of the kinetic theory, of molecules in motion.

In an attempt to discredit the psychological vocabulary of one vernacular, namely, English, Churchland (1984) argued that it must be faulty since it was theory-laden with ‘folk psychology,’ a theory based on mistaken ideas about the nature of beliefs and memories, which are taken to be mental entities. There are no such mental entities, argued Churchland. Folk psychology is false psychological theory. In favor of what terminology should we eliminate the lexicon of everyday life? There is a developing and true theory of cognition, he argued, which is based on a materialist ontology, that of neurophysiology. Thus we should eliminate expressions like ‘pain’ in favor of ‘firing in the c-fibers’ and ‘the sound of the flute’ by an expression for the Fourier analysis of the waveform of the propagated sound wave. There is no mind body problem, because there is no scientifically acceptable vocabulary for referring to and describing the ‘mind’ side of the problematic pair of terms. This is not, be it noted, a proposal to translate the mental vocabulary, term by term, into a physiological vocabulary, but to replace one vocabulary by another, across the board.

5.2 How Idealists Get Rid of Matter

If the assumption of the existence of matter, as the real substrate of the world, is a mistake, then what is left, the mental realm, must be all that there is. There is, therefore, no interaction problem to be solved. This was the route taken by Berkeley (1729). In order to follow his arguments we need to look at a double distinction made famous by Locke (1690), but one which was by no means exclusive to him. Berkeley argued that the distinction between material and mental qualities is bogus. So there is no need for the hypothesis of the existence of matter to be the substance which carries the primary or material properties. According to Locke (1690), ideas are what a person is conscious of, and qualities are the attributes of material things that cause these ideas in a conscious subject. Perception is the having of ideas of qualities. The ideas of primary qualities, such as the bulk, figure, motion, and texture of material things, resemble the material qualities which cause the ideas, while the ideas of secondary qualities, such as experiences of color, taste, and warmth, do not resemble their causes. Though we cannot say just what the secondary qualities of color and so on are in material things, we can say that there must be powers in material things to produce the ideas of them. What grounds these powers? Natural science offers hypotheses about the corpuscular structures on which these powers depend. Newtonian science elegantly fills out these hypotheses with primary qualities, the ‘bulk, figure, motion, and texture of the insensible parts.’ So felt warmth is the effect on a person of the motion of molecules in the stuff that is felt to be warm. It is only too clear that this account is both close to the way physical science seems to work, and highly contentious. How could the movement of molecules cause a feeling that has nothing of motion in it? The mind body problem surfaces in even more intractable form in Locke’s famous theory of perception.

Berkeley’s idealism springs straight from his criticism of the Lockean distinction between primary and secondary qualities. According to Berkeley (1729) the distinction must be rejected, and with it the distinction between qualities and ideas. If these linked dichotomies are abandoned, then the hypothesis of a material substrate to underpin experience is gratuitous. Furthermore, since the properties of this alleged matter are clearly passive, and have nothing of power and activity in them, by dropping the whole scheme the problem of how matter could act on mind disappears. As Berkeley remarks, ‘only spirits are active’ and the most active of all is God.

There is no mind body problem because there is no body in the sense of a material substance, unobservable but foundational to the existence of each human being, a something that lies behind the qualities that we perceive. To be is to be able to be perceived. To perceive some thing is to have an idea of it. Only that which is perceived or perceivable exists, so the world is a world of ideas. And this, Berkeley insists, is the ordinary world we all know well. In a way we should perhaps say that the ordinary world is neither mental nor material, since Berkeley’s argument attacks the roots of this distinction. There is just the world as we perceive it.

6. Expression and Description

Recently the discursive account has taken a deeper and more subtle turn, in Wittgenstein’s querying of the assumption that mental predicates are used to describe states of mind known only to the person who enjoys them. By looking very carefully at the sorts of occasions we use the mental predicates, Wittgenstein (1953) saw that it would be more correct to say that a statement like ‘I have an itch’ expressed one’s feeling rather than described it. The point is this: when we describe something the description and what is described are independent of one another in the sense that the description could be wrong. But an expression is related to the feeling expressed internally, that is to have an itch is not only to have a certain feeling, but to be disposed to do such characteristic things as scratching and saying ‘I itch!’ Only if the material and immaterial predicates were used in descriptions could the relation between the states they severally described be causal. The feeling and the tendency to express it are both necessary components of what is to ‘have an itch,’ ‘be in pain,’ and so on. So in using the first person I do not refer to something within the person, the self. Rather in using first person pronouns, for instance, I express my identity. To be able to use such pronouns is an integral aspect of what it is to have a sense of personal identity.

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