Why is dualism rejected by science

The conclusion that reason is primarily practical takes us beyond this premiss and involves its qualification from a more comprehensive standpoint. But there is this difference from all earlier stages that the discovery of the primacy of practical reason is a final conclusion and not the starting-point of a new stage. Kant goes no further. Instead he erects a barrier against every attempt to go further.

Our acceptance of practical reason and its categorical imperative remains a matter of faith. Our belief in freedom is a necessary but incomprehensible belief and we can comprehend its incomprehensibility.

We can indeed use its necessity as a basis for a reasonable hope that there is another life to bridge the gulf between duty and happiness and a supreme being whose business it is to see that the gulf is bridged.

Nevertheless the Critical Philosophy points the way even if it forbids the attempt to a formal reconstruction which would start from the primacy of the practical and take up into itself the theoretical as an element within the practical. Before we carry this further we must consider the second major criticism of the Critical philosophy which is in respect of its adequacy.

I have said that it is the most adequate of modern philosophies; but it is not fully adequate. It fails to do justice to that aspect of human experience of which religion is the reflective expression.

It is true that in there appeared a treatise written by Kant under the title Religion within the Bounds of Mere Reason. But this work for all its great merits cannot be considered an integral part of the Critical philosophy. It is rather in the nature of an addendum to the Critique of Practical Reason.

For it treats religion not as a distinct field of experience grounded in a form of judgement which claims to be valid in its own right but simply as a set of beliefs which are justifiable pragmatically in so far as they tend to support the rational will in its struggle against the incitements of inclination. There is indeed no room in the compact structure of the Kantian systematic for a separate critique of religion.

In the first Critique the proofs of the existence of God have been shown to be illusory and in the religious field there can be no knowledge and not even in the logical sense a necessary belief.

The most that we can have is a reasonable hope on the condition that we do our duty without regard to happiness in this world. Religion appears as a kind of justifiable mythology concerned wholly with another life and another world; as a sop to the weakness of human nature or a crutch to aid the feebleness of our all too human wills. Above all Kant insists that religion must never be considered as the ground of morality. It is moral experience which provides the ground of religious belief.

Now whatever view we may hold about religion this treatment of the subject cannot be regarded as a critical examination of the claims of religious experience. No great religious teacher could recognize in Kant's account anything that is of central significance to himself.

Paul in the Epistle to the Romans comes in some ways close to Kant in his discussion of the moral law. For I delight in the law of God after the inward man; but I see another law in my members warring against the law of my mind and bringing me into captivity to the law of sin which is in my members.

All have sinned and come short of the glory of God. Paul finds the significance of religion in being set free from the law of sin and death as a matter of grace and not of desert.

But we need not labour what is very obvious. How little evidence there is that Kant's discussion of religion has contributed anything to the purification of religious belief! How much reason there is for considering it one of the factors which have contributed to the idea that religion is unnecessary! What concerns us however is not so much the inadequacy of Kant's treatment of religion but the reason for it.

It would not be enough even if it were true to suggest that Kant himself was not a deeply religious man. For an adequate intellectual critique of religious experience that would not be necessary. His treatment of aesthetic judgement is very adequate yet there is no evidence that Kant was unusually sensitive to art. The adequacy in question is an intellectual adequacy and the reason for it must be a formal one. For thought is inherently private; and any philosophy which takes its stand on the primacy of thought which defines the Self as the Thinker is committed formally to an extreme logical individualism.

It is necessarily egocentric. Whether it is logically committed to solipsism we need not inquire. It may be so. But the point here is a purely formal one. Now the form of religious experience involves the distinction between the first and second persons.

The question of the validity of religious belief is a question of the validity of this form. It must substitute for the second person an object which is thought to possess the characters by which we discriminate persons from things.

God is then conceived as the supreme object of thought and the knowledge of God must signify the determination of this object by means of the categories of the understanding. The necessary failure of this effort to categorize an infinite person is demonstrated by Kant in the Dialectic of the Critique of Pure Reason. But it was already a commonplace of theology; and it misses the point of religious experience totally since the conception of God as the supreme object of the understanding is not a religious but a pseudo-scientific conception.

But even if the universalization of the second person as an infinite Thou is invalid this would not dispose of the problem. We should still have to inquire how the idea valid or not actually arises. What is generalized legitimately or not in the religious use of the term God is a matter of empirical experience.

It is our experience of personal relationship with one another. These two criticisms of Kant's philosophy—of its formal coherence and its formal adequacy—have a common root.

For thought is essentially private. Formally it is the contrary of action; excluding any causal operation upon the object which is known through its activity that is to say upon the Real. However far we carry the process of thought it can never become an action or spontaneously generate an action. We may formulate the dualism in different ways as a dualism of mind and body of mind and matter of theory and practice of appearance and reality of subjective and objective of phenomenal and noumenal worlds but we can never abolish it.

Consequently I can never know another person since thinking about another person can never amount to personal knowledge of him nor even to personal acquaintance. This may be clarified if I give here my reason for thinking that contemporary logical empiricism escapes from the range of the Critical philosophy and belongs to a new emergent phase.

My reason is that it shifts the locus of logical analysis from thought to language and in doing so implicitly rejects the formal dualism which characterizes the two earlier periods of modern philosophy alike. Speech is public. Thus the problem of the form of the personal emerges as the problem of the form of communication.

Contemporary existentialism which concerns itself with the matter of personal experience in its personal character equally and perhaps more consciously exhibits the emergence of the new problem. But here the problem shows a religious face. Kant insisted that we cannot. Is he justified in this? In the end the only answer must be to attempt it; the only refutation of Kant's negative must be to do it.

For the original assertion was intended to make a radical break with philosophical tradition and to establish a new starting-point. By its success it initiated a new philosophical tradition and consequently all criticisms of it within the tradition which it established are internal criticisms which depend upon its acceptance.

They can only be criticisms of the manner of its formulation not of what is formulated. I have therefore both the right and the duty to think for myself and to refuse to accept any authority other than my own reason as a guarantor of truth.

Unless interpreted in the light of this preliminary process it loses a good deal of its significance. The method of doubt is the rejection of authority in operation. Within the body of tradition doubts of its authority had been growing for some centuries.

Their social expression is the formation and spread of heretical sects which challenge the authority of the Church in matters of belief. This had been regarded as an evil a disruption of social unity and a challenge to divinely established authority. The Church considered herself justified in taking the extremest measures for the suppression of heresy. Descartes however has systematized this doubt and set it up as a canon for the proper employment of the intellect in the search for truth.

This too has been accepted by modern thought and it is now so familiar to us that we fail to recognize how paradoxical it is. Is it not prima facie unlikely that the effort to extend doubt systematically to the limits of possibility should issue in an extension of certainty? It would be strange to think that Jones is wrong to think that there is a matter of fact about this. If the reasoning above is correct, one is left with only the first option.

If so, there has to be an absolute matter of fact from the subjective point of view. But the physical examples we have considered show that when something is essentially complex, this cannot be the case.

When there is constitution, degree and overlap of constitution are inevitably possible. So the mind must be simple, and this is possible only if it is something like a Cartesian substance. His worries concerned the cramping effect that matter would have on the range of objects that intellect could accommodate. Parallel modern concerns centre on the restriction that matter would impose on the range of rational processes that we could exhibit.

Some of these concerns are of a technical kind. But there are other less technical and easier to appreciate issues. I will mention four ways in which physicalist theories of thought seem vulnerable to attack by the dualist. There has been a rise or revival of a belief in what is now called cognitive phenomenology , that is, the belief that thoughts, of whatever kind — beliefs, desires, and the whole range of propositional attitude state — are conscious in a more than behavioural functional sense.

The issue is whether, under this constraint, one can give an account for meaningful communication and understanding at all. This is clearly expounded in Dennett ; see also the entry on the frame problem. Numbers, it would seem, are abstract objects, yet our intellects operate with them all the time. How does a physical brain interact with an abstract entity?

A similar problem could be raised for concepts in general; they are abstract, general entities, not physical particulars, yet they are the meat and drink of thinking. For a dualist about intellect there does not appear to be the same problem. The immaterial intellect is precisely the sort of thing that can grasp abstract objects, such as numbers and universals — in the Aristotelian context, the immaterial intellect is the home of forms.

There is still the issue of how this intellectual capacity of the immaterial mind relates to sensory consciousness. According to Aristotle, perception is a wholly embodied process, but for modern dualists, sensory consciousness is not material.

In order to unify the perceptual and intellectual functions of the mind, traditional empiricists tended to be imagists, in their theory of thought, in order to assimilate the intellectual to the sensory, but this assimilation is rejected by those who believe in a distinct cognitive phenomenology, as mentioned in a above. The issue of how these two functions of mind are related in dualism is, it seems to me, insufficiently investigated.

Armstrong in his is a striking exception to this, accepting an in re theory of universals. I will not discuss a further, as it is discussed in section 5 of the entry on phenomenal intentionality , An immaterialist response to d can be found in Robinson Both b and c seem to draw out the claim that a material system lacks understanding.

Searle imagines himself in a room with a letter box through which strings of symbols are posted in, and, following a book of rules, he puts out symbols which the rules dictate, given the strings he is receiving. In fact, Searle says, he has been conducting a conversation in Chinese, because the symbols are Chinese script, and the rules those on which a Chinese computer might work, but he has not understood a word. Therefore neither does a computer understand, so we, understanding creatures, are not computers.

A blow was struck against the computational theory of thought when, in , Fodor produced his The Mind Does Not Work That Way , in which he made clear his belief that the kind of computationalism that he had been describing and developing ever since the s only fits sub-personal informational processing, not conscious, problem solving thought.

One physicalist response to these challenges is to say that they apply only to the classical computing model, and are avoided by connectionist theories. Classical computing works on rules of inference like those of standard logic, but connectionism is rather a form of associationism, which is supposedly closer to the way in which the brain works.

See the entry on Connectionism. But Gary Marcus — see Other Internet Resources and others have pointed out the ways in which these impressive machines are quite different from human thought. We can learn things with very few trials because we latch on to abstract relationships, whereas the machine requires many — perhaps thousands or millions — of examples to try to catch extensionally what we get by the abstract or intensional relation.

The dualist might sum up the situation on thought in the following way. The case against physicalist theories of sensation is that it is unbelievable that what it feels like to be struck hard on the nose is itself either just a case of being disposed or caused to engage in certain behaviours, or that what it feels like is not fundamental to the way you do react.

Similarly, the dualist about thought will say, when you are, for example, engaged in a philosophical discussion, and you make a response to your interlocutor, it is obvious that you are intending to respond to what you thought he or she meant and are concentrating on what what you intend to say means. It seems as bizarre to say that this is a bye-product of processes to which meaning is irrelevant, as it is to claim the same about sensory consciousness.

You are, in other words, as fundamentally a semantically driven engine, as you are a sensorily consciously driven one. Perhaps, in the case of a sophisticated conversation, the fundamentality of meaning, and of conscious reflection, as a driver is even more obvious than in the case of sensation. A dualist could, it seems, argue that Plato was right in claiming that intellect necessarily has an affinity with the realm of abstract entities, and Aristotle was right to think that no material or mechanical system could capture the flexibility built into genuine understanding.

We have already discussed the problem of interaction. In this section we shall consider two other facets of dualism that worry critics. First, there is what one might term the queerness of the mental if conceived of as non-physical. Second there is the difficulty of giving an account of the unity of the mind. We shall consider this latter as it faces both the bundle theorist and the substance dualist.

Mental states are characterised by two main properties, subjectivity, otherwise known as privileged access, and intentionality. Physical objects and their properties are sometimes observable and sometimes not, but any physical object is equally accessible, in principle, to anyone. From the right location, we could all see the tree in the quad, and, though none of us can observe an electron directly, everyone is equally capable of detecting it in the same ways using instruments.

But the possessor of mental states has a privileged access to them that no-one else can share. This suggests to some philosophers that minds are not ordinary occupants of physical space. Physical objects are spatio-temporal, and bear spatio-temporal and causal relations to each other.

Mental states seem to have causal powers, but they also possess the mysterious property of intentionality — being about other things — including things like Zeus and the square root of minus one, which do not exist.

The nature of the mental is both queer and elusive. Ghosts are mysterious and unintelligible: machines are composed of identifiable parts and work on intelligible principles. But this contrast holds only if we stick to a Newtonian and common-sense view of the material. Think instead of energy and force-fields in a space-time that possesses none of the properties that our senses seem to reveal: on this conception, we seem to be able to attribute to matter nothing beyond an abstruse mathematical structure.

Whilst the material world, because of its mathematicalisation, forms a tighter abstract system than mind, the sensible properties that figure as the objects of mental states constitute the only intelligible content for any concrete picture of the world that we can devise.

Perhaps the world within the experiencing mind is, once one considers it properly, no more — or even less — queer than the world outside it. Whether one believes that the mind is a substance or just a bundle of properties, the same challenge arises, which is to explain the nature of the unity of the immaterial mind. For the Cartesian, that means explaining how he understands the notion of immaterial substance. For the Humean, the issue is to explain the nature of the relationship between the different elements in the bundle that binds them into one thing.

Neither tradition has been notably successful in this latter task: indeed, Hume, in the appendix to the Treatise , declared himself wholly mystified by the problem, rejecting his own initial solution though quite why is not clear from the text. If the mind is only a bundle of properties, without a mental substance to unite them, then an account is needed of what constitutes its unity. The only route appears to be to postulate a primitive relation of co-consciousness in which the various elements stand to each other.

There are two strategies which can be used to attack the bundle theory. One is to claim that our intuitions favour belief in a subject and that the arguments presented in favour of the bundle alternative are unsuccessful, so the intuition stands. The other is to try to refute the theory itself.

Foster , —9 takes the former path. This is not effective against someone who thinks that metaphysical economy gives a prima facie priority to bundle theories, on account of their avoiding mysterious substances. The core objection to bundle theories see, for example, Armstrong , 21—3 is that, because it takes individual mental contents as its elements, such contents should be able to exist alone, as could the individual bricks from a house.

Hume accepted this consequence, but most philosophers regard it as absurd. There could not be a mind that consisted of a lone pain or red after-image, especially not of one that had detached itself from the mind to which it had previously belonged. Therefore it makes more sense to think of mental contents as modes of a subject. Bundle theorists tend to take phenomenal contents as the primary elements in their bundle. Seeing the problem in this way has obvious Humean roots.

This atomistic conception of the problem becomes less natural if one tries to accommodate other kinds of mental activity and contents.

How are acts of conceptualising, attending to or willing with respect to, such perceptual contents to be conceived? These kinds of mental acts seem to be less naturally treated as atomic elements in a bundle, bound by a passive unity of apperception. William James , vol.

James attributes to these Thoughts acts of judging, attending, willing etc, and this may seem incoherent in the absence of a genuine subject. But there is also a tendency to treat many if not all aspects of agency as mere awareness of bodily actions or tendencies, which moves one back towards a more normal Humean position.

But see Sprigge , 84—97, for an excellent, sympathetic discussion. The problem is to explain what kind of a thing an immaterial substance is, such that its presence explains the unity of the mind. The answers given can be divided into three kinds. There are two problems with this approach. Second, and connectedly, it is not clear in what sense such stuff is immaterial, except in the sense that it cannot be integrated into the normal scientific account of the physical world.

Why is it not just an aberrant kind of physical stuff? Account a allowed the immaterial substance to have a nature over and above the kinds of state we would regard as mental. The consciousness account does not.

The most obvious objection to this theory is that it does not allow the subject to exist when unconscious. This forces one to take one of four possible theories. He has half escaped because he does not attribute non-mental properties to the self, but he is still captured by trying to explain what it is made of. The reason is that, even when we have acknowledged that basic subjects are wholly non-physical, we still tend to approach the issue of their essential natures in the shadow of the physical paradigm.

One can interpret Berkeley as implying that there is more to the self than introspection can capture, or we can interpret him as saying that notions, though presenting stranger entities than ideas, capture them just as totally. Varieties of Dualism: Ontology 2. Varieties of Dualism: Interaction 3. Arguments for Dualism 4. Problems for Dualism 5. The ontological question: what are mental states and what are physical states?

Is one class a subclass of the other, so that all mental states are physical, or vice versa? Or are mental states and physical states entirely distinct? The causal question: do physical states influence mental states? Do mental states influence physical states? If so, how? The problem of consciousness: what is consciousness? How is it related to the brain and the body? The problem of intentionality: what is intentionality?

The problem of the self: what is the self? Other aspects of the mind-body problem arise for aspects of the physical. For example: The problem of embodiment: what is it for the mind to be housed in a body?

What is it for a body to belong to a particular subject? Varieties of Dualism: Ontology There are various ways of dividing up kinds of dualism. Varieties of Dualism: Interaction If mind and body are different realms, in the way required by either property or substance dualism, then there arises the question of how they are related.

For more detailed treatment and further reading on this topic, see the entry epiphenomenalism. I can never catch myself at any time without a perception, and can never observe any thing but the perception. Somewhat surprisingly, it is not very clear just what his worry was, but it is expressed as follows: In short there are two principles, which I cannot render consistent; nor is it in my power to renounce either of them, viz.

A natural response to Hume would be to say that, even if we cannot detect ourselves apart from our perceptions our conscious experiences we can at least detect ourselves in them … Surely I am aware of [my experience], so to speak, from the inside — not as something presented, but as something which I have or as the experiential state which I am in … and this is equivalent to saying that I detect it by being aware of myself being visually aware.

If the bundle theory were true, then it should be possible to identify mental events independently of, or prior to, identifying the person or mind to which they belong. It is not possible to identify mental events in this way. Therefore, The bundle theory is false. Lowe defends this argument and argues for 2 as follows.

What is wrong with the [bundle] theory is that … it presupposes, untenably,that an account of the identity conditions of psychological modes can be provided which need not rely on reference to persons. But it emerges that the identity of any psychological mode turns on the identity of the person that possesses it. What this implies is that psychological modes are essentially modes of persons, and correspondingly that persons can be conceived of as substances.

He says: The mind is a kind of theatre where several perceptions successively make their appearance; pass, re-pass, glide away and mingle in an infinite variety of postures and situations.

We can scale counterfactual suggestions as follows: This table might have been made of ice. This table might have been made of a different sort of wood.

Any present state of consciousness that I can imagine either is or is not mine. There is no question of degree here. Perhaps, in the case of a sophisticated conversation, the fundamentality of meaning, and of conscious reflection, as a driver is even more obvious than in the case of sensation A dualist could, it seems, argue that Plato was right in claiming that intellect necessarily has an affinity with the realm of abstract entities, and Aristotle was right to think that no material or mechanical system could capture the flexibility built into genuine understanding.

Problems for Dualism We have already discussed the problem of interaction. Bibliography Almog, J. Hamlyn trans. Armstrong, D. Averill, E. Ayer, A. Baker, M. Goetz eds. Benacerraf, P. Berkeley, G.

Luce and T. Jessop eds. Bricke, J. Broad, C. Chalmers, D. Collins, C. Collins, R. Crane, T. Cucu, A. Dainton, B. Davidson, D. Foster and J. Swanson eds. Dennett, D. Hookway ed. Descartes, R. Cottingham trans. Ducasse, C. Hook ed. Understanding and learning the history of any subject helps us. Theories devoted to the mind-body problem first address the root of the dilemma: is the mind and body a single entity, or are they separate? This question separates the mind-body problem into two major schools of thought: monism and dualism.

Monists hold that only one type of substance, mind or matter, compose existence Wiltshire. The idealism theory supports monist perspectives by claiming the mind is the only substance responsible for existence and perception of reality. The mind was capable of free will, which has a religious connotation in that it denotes that a higher force, or God, is not controlling the minds of humans but then their minds are in control of their bodies.

Then, the body was a scientific vessel that was inhabited by the Soul, or the mind, for a temporary amount of time. Apparently, the mind could not be explained through science but rather religion whereas the body could only be explained and studied through science and not. There has been a persistent question throughout the ages, how are the mind and body related? This question of if there truly is a mind, and if there is, how is it linked to the body has been the center of many debates since the beginning of psychology.

The solution for materialists and monists is there is one type of reality, and that is matter, and everything derives from that. There are other psychologist that does not believe in the extreme nature of a singular type of reality. We can explain the evolution from the unicellular stage to present complexities by means of random mutations and natural selection in the species case and through the accretion of matter through nutritional intake in the individual case.

But if we, as species or individuals, began as wholly physical beings and nothing nonphysical was later added, then we are still wholly physical creatures. Thus, dualism is false. The above arguments are only as strong as our reasons for thinking that we began as wholly material beings and that nothing non-physical was later added.

Some people, particularly the religious, will object that macro-evolution of a species is problematic or that God might well have infused the developing fetus with a soul at some point in the developmental process traditionally at quickening. Most contemporary philosophers of mind put little value in these rejoinders. Others argue that dualism is scientifically unacceptable because it violates the well-established principle of the conservation of energy. Interactionists argue that mind and matter causally interact.

But if the spiritual realm is continually impinging on the universe and effecting changes, the total level of energy in the cosmos must be increasing or at least fluctuating. This is because it takes physical energy to do physical work. If the will alters states of affairs in the world such as the state of my brain , then mental energy is somehow converted into physical energy.

At the point of conversion, one would anticipate a physically inexplicable increase in the energy present within the system. First, they could deny the sacredness of the principle of the conservation of energy. This would be a desperate measure. The principle is too well established and its denial too ad hoc. Second, the dualist might offer that mind does contribute energy to our world, but that this addition is so slight, in relation to our means of detection, as to be negligible.

This is really a re-statement of the first reply above, except that here the principle is valid in so far as it is capable of verification. Science can continue as usual, but it would be unreasonable to extend the law beyond our ability to confirm it experimentally.

That would be to step from the empirical to the speculative—the very thing that the materialist objects to in dualism. The third option sidesteps the issue by appealing to another, perhaps equally valid, principle of physics.

Keith Campbell writes:. The indeterminacy of quantum laws means that any one of a range of outcomes of atomic events in the brain is equally compatible with known physical laws. And differences on the quantum scale can accumulate into very great differences in overall brain condition. So there is some room for spiritual activity even within the limits set by physical law.

There could be, without violation of physical law, a general spiritual constraint upon what occurs inside the head. Further, it should be remembered that the conservation of energy is designed around material interaction; it is mute on how mind might interact with matter.

The conservation of energy argument points to a more general complaint often made against dualism: that interaction between mental and physical substances would involve a causal impossibility. Since the mind is, on the Cartesian model, immaterial and unextended, it can have no size, shape, location, mass, motion or solidity. How then can minds act on bodies? What sort of mechanism could convey information of the sort bodily movement requires, between ontologically autonomous realms?

To suppose that non-physical minds can move bodies is like supposing that imaginary locomotives can pull real boxcars. Unfortunately, this expedient proved a dead-end, since it is as incomprehensible how the mind could initiate motion in the animal spirits as in matter itself.

These problems involved in mind-body causality are commonly considered decisive refutations of interactionism. However, many interesting questions arise in this area.

Where does the interaction occur? What is the nature of the interface between mind and matter? How are volitions translated into states of affairs? It is useful to be reminded, however, that to be bewildered by something is not in itself to present an argument against, or even evidence against, the possibility of that thing being a matter of fact.

Nothing much. It only follows that dualists do not know everything about metaphysics. But so what? Why should the dualist be any different?

In short, dualists can argue that they should not be put on the defensive by the request for clarification about the nature and possibility of interaction or by the criticism that they have no research strategy for producing this clarification.

The objection that minds and bodies cannot interact can be the expression of two different sorts of view. On the one hand, the detractor may insist that it is physically impossible that minds act on bodies. If this means that minds, being non-physical, cannot physically act on bodies, the claim is true but trivial. If it means that mind-body interaction violates the laws of physics such as the first law of thermodynamics, discussed above , the dualist can reply that minds clearly do act on bodies and so the violation is only apparent and not real.

After all, if we do things for reasons, our beliefs and desires cause some of our actions. If the materialist insists that we are able to act on our beliefs, desires and perceptions only because they are material and not spiritual, the dualist can turn the tables on his naturalistic opponents and ask how matter, regardless of its organization, can produce conscious thoughts, feelings and perceptions.

How, the dualist might ask, by adding complexity to the structure of the brain, do we manage to leap beyond the quantitative into the realm of experience? The relationship between consciousness and brain processes leaves the materialist with a causal mystery perhaps as puzzling as that confronting the dualist.

On the other hand, the materialist may argue that it is a conceptual truth that mind and matter cannot interact. This, however, requires that we embrace the rationalist thesis that causes can be known a priori. Many prefer to assert that causation is a matter for empirical investigation. Otherwise, anything can be the cause of anything else. If volitions are constantly conjoined with bodily movements and regularly precede them, they are Humean causes.

In short, if Hume is correct, we cannot refute dualism a priori by asserting that transactions between minds and bodies involve links where, by definition, none can occur. Some, such as Ducasse , 88; cf. Dicker pp. While it makes sense to ask how depressing the accelerator causes the automobile to speed up, it makes no sense to ask how pressing the accelerator pedal causes the pedal to move. We can sensibly ask how to spell a word in sign language, but not how to move a finger.

One final note: epiphenomenalism, like occasionalism and parallelism, is a dualistic theory of mind designed, in part, to avoid the difficulties involved in mental-physical causation although occasionalism was also offered by Malebranche as an account of seemingly purely physical causation. According to epiphenomenalism, bodies are able to act on minds, but not the reverse. The causes of behavior are wholly physical.

As such, we need not worry about how objects without mass or physical force can alter behavior. Nor need we be concerned with violations of the conservation of energy principle since there is little reason to suppose that physical energy is required to do non-physical work. If bodies affect modifications in the mental medium, that need not be thought to involve a siphoning of energy from the world to the psychic realm.

On this view, the mind may be likened to the steam from a train engine; the steam does not affect the workings of the engine but is caused by it. Unfortunately, epiphenomenalism avoids the problem of interaction only at the expense of denying the common-sense view that our states of mind have some bearing on our conduct. For many, epiphenomenalism is therefore not a viable theory of mind.

For a defense of the common-sense claim that beliefs and attitudes and reasons cause behavior, see Donald Davidson. The correlation and dependence argument against dualism begins by noting that there are clear correlations between certain mental events and neural events say, between pain and a-fiber or c-fiber stimulation.

Moreover, as demonstrated in such phenomena as memory loss due to head trauma or wasting disease, the mind and its capacities seem dependent upon neural function. The simplest and best explanation of this dependence and correlation is that mental states and events are neural states and events and that pain just is c-fiber stimulation. This would be the argument employed by an identity theorist. A functionalist would argue that the best explanation for the dependence and correlation of mental and physical states is that, in humans, mental states are brain states functionally defined.

Descartes himself anticipated an objection like this and argued that dependence does not strongly support identity. He illustrates by means of the following example: a virtuoso violinist cannot manifest his or her ability if given an instrument in deplorable or broken condition. If, like the violin, the brain is in a severely diseased or injurious state, the mind cannot demonstrate its abilities; they of necessity remain private and unrevealed. However, for all we know, the mind still has its full range of abilities, but is hindered in its capacity to express them.

As for correlation, interactionism actually predicts that mental events are caused by brain events and vice versa, so the fact that perceptions are correlated with activity in the visual cortex does not support materialism over this form of dualism. Property dualists agree with the materialists that mental phenomena are dependent upon physical phenomena, since the fomer are non-physical attributes of the latter.

See Churchland, , p. Other materialist responses will not be considered here. The problem of how we can know other minds has been used as follows to refute dualism. If the mind is not publicly observable, the existence of minds other than our own must be inferred from the behavior of the other person or organism.

The reliability of this inference is deeply suspect, however, since we only know that certain mental states cause characteristic behavior from our own case. To extrapolate to the population as a whole from the direct inspection of a single example, our own case, is to make the weakest possible inductive generalization.

Hence, if dualism is true, we cannot know that other people have minds at all. But common sense tell us that others do have minds. Since common sense can be trust, dualism is false. This problem of other minds , to which dualism leads so naturally, is often used to support rival theories such as behaviorism , the mind-brain identity theory , or functionalism though functionalists sometimes claim that their theory is consistent with dualism.

If mental states are just behavioral states, brain states, or functional states, then we can verify that others have mental states on the basis of publicly observable phenomena, thereby avoiding skepticism about other selves. Materialist theories are far less vulnerable to the problem of other minds than dualist theories, though even here other versions of the problem stubbornly reappear.

Deciding to define mental states behaviorally does not mean that mental states are behavioral, and it is controversial whether attempts to reduce mentality to behavioral, brain, or functional states have been successful. Of two outwardly indistinguishable dopplegangers, one might have experience and the other none.

The other would be like an automaton. The problem for the materialist then becomes not the problem of other minds, but the problem of other qualia. The latter seems almost as severe an affront to common sense as the former. For an interesting related discussion, see Churchland on eliminative materialism, , pp. We earlier observed that some philosophers, such as Hume, have objected that supposing that the mind is a thinking thing is not warranted since all we apprehend of the self by introspection is a collection of ideas but never the mind that purportedly has these ideas.

All we are therefore left with is a stream of impressions and ideas but no persisting, substantial self to constitute personal identity. If there is no substratum of thought, then substance dualism is false. Kant, too, denied that the mind is a substance. Mind is simply the unifying factor that is the logical preliminary to experience.