What is the difference between substance dualism and property dualism

We never differentiated between the mind and the soul, and I might be oversimplifying matters, but I think that they are the same. Right, the terminology can get confusing. For substance dualists, the mind is a soul, that is, the mind is an immaterial thing. For identity theorists, on the other hand, the mind is identical to the brain or, mental states are identical to brain states. Perhaps mind is same as spirit and dies with the body brain but soul lives on? If God intended you to know that it would already be a known fact.

Even if the brain and mind are one, God can still bring our soul to his gates. Always remember to walk by faith not by sight. What science says bay be true to what religion says. Never doubt the almighty power of God.

That is why you have a mental capacity and your own free-will to think and believe as you choose. Levine J Purple haze: the puzzle of consciousness. Kim J Mind in a physical world. Springer International, Berlin Google Scholar. Swinburne R The evolution of the soul. Clarendon Press, Oxford Google Scholar. Papineau D Thinking about consciousness. Kripke S Naming and necessity. Blackwell, Oxford Google Scholar. Lowe 1 1. See, for example, Aquinas , Part I, questions 75 and But though the form and, hence, the intellect with which it is identical are the substance of the human person, they are not the person itself.

The soul, though an immaterial substance, is the person only when united with its body. Without the body, those aspects of its personal memory that depend on images which are held to be corporeal will be lost.

See Aquinas , Part I, question Descartes was a substance dualist. He believed that there were two kinds of substance: matter, of which the essential property is that it is spatially extended; and mind, of which the essential property is that it thinks.

For Aristotle, there is no exact science of matter. How matter behaves is essentially affected by the form that is in it.

You cannot combine just any matter with any form — you cannot make a knife out of butter, nor a human being out of paper — so the nature of the matter is a necessary condition for the nature of the substance. Matter is a determinable made determinate by form.

This was how Aristotle thought that he was able to explain the connection of soul to body: a particular soul exists as the organizing principle in a particular parcel of matter. If matter is atomic, then it is already a collection of determinate objects in its own right, and it becomes natural to regard the properties of macroscopic substances as mere summations of the natures of the atoms.

Although, unlike most of his fashionable contemporaries and immediate successors, Descartes was not an atomist, he was, like the others, a mechanist about the properties of matter. Bodies are machines that work according to their own laws. Except where there are minds interfering with it, matter proceeds deterministically, in its own right.

Descartes opted for the pineal gland, mainly because it is not duplicated on both sides of the brain, so it is a candidate for having a unique, unifying function. The main uncertainty that faced Descartes and his contemporaries, however, was not where interaction took place, but how two things so different as thought and extension could interact at all.

This would be particularly mysterious if one had an impact view of causal interaction, as would anyone influenced by atomism, for whom the paradigm of causation is like two billiard balls cannoning off one another. The appropriate states of mind and body were only the occasions for such intervention, not real causes. Now it would be convenient to think that occasionalists held that all causation was natural except for that between mind and body.

In fact they generalized their conclusion and treated all causation as directly dependent on God. Why this was so, we cannot discuss here. Locke, as a moderate empiricist, accepted that there were both material and immaterial substances.

Berkeley famously rejected material substance, because he rejected all existence outside the mind. Finally, he decided that the self, conceived as something over and above the ideas of which it was aware, was essential for an adequate understanding of the human person. Although the self and its acts are not presented to consciousness as objects of awareness, we are obliquely aware of them simply by dint of being active subjects.

Hume rejected such claims, and proclaimed the self to be nothing more than a concatenation of its ephemeral contents. In fact, Hume criticised the whole conception of substance for lacking in empirical content: when you search for the owner of the properties that make up a substance, you find nothing but further properties.

This position has been labelled bundle dualism , and it is a special case of a general bundle theory of substance , according to which objects in general are just organised collections of properties. The problem for the Humean is to explain what binds the elements in the bundle together. This is an issue for any kind of substance, but for material bodies the solution seems fairly straightforward: the unity of a physical bundle is constituted by some form of causal interaction between the elements in the bundle.

For the mind, mere causal connection is not enough; some further relation of co-consciousness is required. We shall see in 5. His bundle theory is a theory about the nature of the unity of the mind. As a theory about this unity, it is not necessarily dualist. Parfit , and Shoemaker , ch. In general, physicalists will accept it unless they wish to ascribe the unity to the brain or the organism as a whole.

Before the bundle theory can be dualist one must accept property dualism, for more about which, see the next section. A crisis in the history of dualism came, however, with the growing popularity of mechanism in science in the nineteenth century. This means that everything that happens follows from and is in accord with the laws of physics.

There is, therefore, no scope for interference in the physical world by the mind in the way that interactionism seems to require. According to the mechanist, the conscious mind is an epiphenomenon a notion given general currency by T. Huxley : that is, it is a by-product of the physical system which has no influence back on it.

In this way, the facts of consciousness are acknowledged but the integrity of physical science is preserved. However, many philosophers found it implausible to claim such things as the following; the pain that I have when you hit me, the visual sensations I have when I see the ferocious lion bearing down on me or the conscious sense of understanding I have when I hear your argument — all have nothing directly to do with the way I respond.

It is very largely due to the need to avoid this counterintuitiveness that we owe the concern of twentieth century philosophy to devise a plausible form of materialist monism.

But, although dualism has been out of fashion in psychology since the advent of behaviourism Watson and in philosophy since Ryle , the argument is by no means over. Some distinguished neurologists, such as Sherrington and Eccles Popper and Eccles have continued to defend dualism as the only theory that can preserve the data of consciousness. Amongst mainstream philosophers, discontent with physicalism led to a modest revival of property dualism in the last decade of the twentieth century.

At least some of the reasons for this should become clear below. There are various ways of dividing up kinds of dualism.

One natural way is in terms of what sorts of things one chooses to be dualistic about. The most common categories lighted upon for these purposes are substance and property , giving one substance dualism and property dualism. There is, however, an important third category, namely predicate dualism.

As this last is the weakest theory, in the sense that it claims least, I shall begin by characterizing it. Predicate dualism is the theory that psychological or mentalistic predicates are a essential for a full description of the world and b are not reducible to physicalistic predicates.

For a mental predicate to be reducible, there would be bridging laws connecting types of psychological states to types of physical ones in such a way that the use of the mental predicate carried no information that could not be expressed without it.

An example of what we believe to be a true type reduction outside psychology is the case of water, where water is always H 2 O: something is water if and only if it is H 2 O. But the terms in many of the special sciences that is, any science except physics itself are not reducible in this way.

These states are defined more by what they do than by their composition or structure. Their names are classified as functional terms rather than natural kind terms. It goes with this that such kinds of state are multiply realizable ; that is, they may be constituted by different kinds of physical structures under different circumstances. Because of this, unlike in the case of water and H 2 O, one could not replace these terms by some more basic physical description and still convey the same information.

It is widely agreed that many, if not all, psychological states are similarly irreducible, and so psychological predicates are not reducible to physical descriptions and one has predicate dualism. The classic source for irreducibility in the special sciences in general is Fodor , and for irreducibility in the philosophy of mind, Davidson Whereas predicate dualism says that there are two essentially different kinds of predicates in our language , property dualism says that there are two essentially different kinds of property out in the world.

Property dualism can be seen as a step stronger than predicate dualism. One might say that we need more than the language of physics to describe and explain the weather, but we do not need more than its ontology. There is token identity between each individual hurricane and a mass of atoms, even if there is no type identity between hurricanes as kinds and some particular structure of atoms as a kind.

Genuine property dualism occurs when, even at the individual level, the ontology of physics is not sufficient to constitute what is there. The irreducible language is not just another way of describing what there is, it requires that there be something more there than was allowed for in the initial ontology. In the case of mind, property dualism is defended by those who argue that the qualitative nature of consciousness is not merely another way of categorizing states of the brain or of behaviour, but a genuinely emergent phenomenon.

There are two important concepts deployed in this notion. One is that of substance , the other is the dualism of these substances. A substance is characterized by its properties, but, according to those who believe in substances, it is more than the collection of the properties it possesses, it is the thing which possesses them. So the mind is not just a collection of thoughts, but is that which thinks, an immaterial substance over and above its immaterial states.

Properties are the properties of objects. If one is a property dualist, one may wonder what kinds of objects possess the irreducible or immaterial properties in which one believes. One can use a neutral expression and attribute them to persons , but, until one has an account of person , this is not explanatory. One might attribute them to human beings qua animals, or to the brains of these animals. Then one will be holding that these immaterial properties are possessed by what is otherwise a purely material thing.

But one may also think that not only mental states are immaterial, but that the subject that possesses them must also be immaterial. Then one will be a dualist about that to which mental states and properties belong as well about the properties themselves.

Now one might try to think of these subjects as just bundles of the immaterial states. But if one thinks that the owner of these states is something quite over and above the states themselves, and is immaterial, as they are, one will be a substance dualist. Lowe, for example, is a substance dualist, in the following sense. He holds that a normal human being involves two substances, one a body and the other a person. The latter is not, however, a purely mental substance that can be defined in terms of thought or consciousness alone, as Descartes claimed.

But persons and their bodies have different identity conditions and are both substances, so there are two substances essentially involved in a human being, hence this is a form of substance dualism. Lowe claims that his theory is close to P.

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. Common sense tells us that they interact: thoughts and feelings are at least sometimes caused by bodily events and at least sometimes themselves give rise to bodily responses.

I shall now consider briefly the problems for interactionism, and its main rivals, epiphenomenalism and parallelism. Interactionism is the view that mind and body — or mental events and physical events — causally influence each other. That this is so is one of our common-sense beliefs, because it appears to be a feature of everyday experience.

The physical world influences my experience through my senses, and I often react behaviourally to those experiences.

My thinking, too, influences my speech and my actions. There is, therefore, a massive natural prejudice in favour of interactionism. It has been claimed, however, that it faces serious problems some of which were anticipated in section 1. The simplest objection to interaction is that, in so far as mental properties, states or substances are of radically different kinds from each other, they lack that communality necessary for interaction.

But if causation is either by a more ethereal force or energy or only a matter of constant conjunction, there would appear to be no problem in principle with the idea of interaction of mind and body. Even if there is no objection in principle, there appears to be a conflict between interactionism and some basic principles of physical science. For example, if causal power was flowing in and out of the physical system, energy would not be conserved, and the conservation of energy is a fundamental scientific law.

Various responses have been made to this. One suggestion is that it might be possible for mind to influence the distribution of energy, without altering its quantity. See Averill and Keating Another response is to challenge the relevance of the conservation principle in this context. This approach has been termed conditionality , namely the view that conservation is conditional on the physical system being closed, that is, that nothing non-physical is interacting or interfering with it, and, of course, the interactionist claims that this condition is, trivially, not met.

That conditionality is the best line for the dualist to take, and that other approaches do not work, is defended in Pitts and Cucu and Pitts This, they claim, makes the plausibility of interactionism an empirical matter which only close investigation on the fine operation of the brain could hope to settle. Cucu, in a separate article , claims to find critical neuronal events which do not have sufficient physical explanation.

This claim clearly needs further investigation. Robins Collins has claimed that the appeal to conservation by opponents of interactionism is something of a red herring because conservation principles are not ubiquitous in physics. He argues that energy is not conserved in general relativity, in quantum theory, or in the universe taken as a whole. Why then, should we insist on it in mind-brain interaction?

This is a very natural assumption, but it is not justified if causal overdetermination of behaviour is possible. There could then be a complete physical cause of behaviour, and a mental one. The strongest intuitive objection against overdetermination is clearly stated by Mills , who is himself a defender of overdetermination. For X to be a cause of Y , X must contribute something to Y. The only way a purely mental event could contribute to a purely physical one would be to contribute some feature not already determined by a purely physical event.

But if physical closure is true, there is no feature of the purely physical effect that is not contributed by the purely physical cause. Hence interactionism violates physical closure after all. Mills says that this argument is invalid, because a physical event can have features not explained by the event which is its sufficient cause. The opponent of overdetermination could perhaps reply that his principle applies, not to every feature of events, but to a subgroup — say, intrinsic features, not merely relational or comparative ones.

It is this kind of feature that the mental event would have to cause, but physical closure leaves no room for this. These matters are still controversial. The problem with closure of physics may be radically altered if physical laws are indeterministic, as quantum theory seems to assert. If physical laws are deterministic, then any interference from outside would lead to a breach of those laws. But if they are indeterministic, might not interference produce a result that has a probability greater than zero, and so be consistent with the laws?

This way, one might have interaction yet preserve a kind of nomological closure, in the sense that no laws are infringed. Because it involves assessing the significance and consequences of quantum theory, this is a difficult matter for the non-physicist to assess. Some argue that indeterminacy manifests itself only on the subatomic level, being cancelled out by the time one reaches even very tiny macroscopic objects: and human behaviour is a macroscopic phenomenon. For discussion of this, see Eccles , , and Popper and Eccles Still others argue that quantum indeterminacy manifests itself directly at a high level, when acts of observation collapse the wave function, suggesting that the mind may play a direct role in affecting the state of the world Hodgson ; Stapp If the reality of property dualism is not to be denied, but the problem of how the immaterial is to affect the material is to be avoided, then epiphenomenalism may seem to be the answer.

According to this theory, mental events are caused by physical events, but have no causal influence on the physical. I have introduced this theory as if its point were to avoid the problem of how two different categories of thing might interact. In fact, it is, at best, an incomplete solution to this problem. If it is mysterious how the non-physical can have it in its nature to influence the physical, it ought to be equally mysterious how the physical can have it in its nature to produce something non-physical.

But that this latter is what occurs is an essential claim of epiphenomenalism. For development of this point, see Green , — There are at least three serious problems for epiphenomenalism. First, as I indicated in section 1 , it is profoundly counterintuitive. What could be more apparent than that it is the pain that I feel that makes me cry, or the visual experience of the boulder rolling towards me that makes me run away?

At least one can say that epiphenomenalism is a fall-back position: it tends to be adopted because other options are held to be unacceptable. The second problem is that, if mental states do nothing, there is no reason why they should have evolved. This objection ties in with the first: the intuition there was that conscious states clearly modify our behaviour in certain ways, such as avoiding danger, and it is plain that they are very useful from an evolutionary perspective.

Frank Jackson replies to this objection by saying that it is the brain state associated with pain that evolves for this reason: the sensation is a by-product. Evolution is full of useless or even harmful by-products. For example, polar bears have evolved thick coats to keep them warm, even though this has the damaging side effect that they are heavy to carry.

But with mental states, dualistically conceived, the situation is quite the opposite. The laws of physical nature which, the mechanist says, make brain states cause behaviour, in no way explain why brain states should give rise to conscious ones.

The laws linking mind and brain are what Feigl calls nomological danglers , that is, brute facts added onto the body of integrated physical law. Why there should have been by-products of that kind seems to have no evolutionary explanation. The third problem concerns the rationality of belief in epiphenomenalism, via its effect on the problem of other minds. It is natural to say that I know that I have mental states because I experience them directly.

But how can I justify my belief that others have them? I know that certain of my mental states are correlated with certain pieces of behaviour, and so I infer that similar behaviour in others is also accompanied by similar mental states. Many hold that this is a weak argument because it is induction from one instance, namely, my own.

I seem to know from my own case that mental events can be the explanation of behaviour, and I know of no other candidate explanation for typical human behaviour, so I postulate the same explanation for the behaviour of others. But if epiphenomenalism is true, my mental states do not explain my behaviour and there is a physical explanation for the behaviour of others.

It is explanatorily redundant to postulate such states for others. I know, by introspection, that I have them, but is it not just as likely that I alone am subject to this quirk of nature, rather than that everyone is? The epiphenomenalist wishes to preserve the integrity of physical science and the physical world, and appends those mental features that he cannot reduce. The parallelist preserves both realms intact, but denies all causal interaction between them. They run in harmony with each other, but not because their mutual influence keeps each other in line.

That they should behave as if they were interacting would seem to be a bizarre coincidence. This is why parallelism has tended to be adopted only by those — like Leibniz — who believe in a pre-established harmony, set in place by God. The progression of thought can be seen as follows. Descartes believes in a more or less natural form of interaction between immaterial mind and material body. Malebranche thought that this was impossible naturally, and so required God to intervene specifically on each occasion on which interaction was required.

Leibniz decided that God might as well set things up so that they always behaved as if they were interacting, without particular intervention being required. Outside such a theistic framework, the theory is incredible. One category of arguments for dualism is constituted by the standard objections against physicalism. Because this argument has its own entry see the entry qualia: the knowledge argument , I shall deal relatively briefly with it here.

One should bear in mind, however, that all arguments against physicalism are also arguments for the irreducible and hence immaterial nature of the mind and, given the existence of the material world, are thus arguments for dualism. The knowledge argument asks us to imagine a future scientist who has lacked a certain sensory modality from birth, but who has acquired a perfect scientific understanding of how this modality operates in others.

Suppose that Harpo, thanks to developments in neurosurgery, has an operation which finally enables him to hear. It is suggested that he will then learn something he did not know before, which can be expressed as what it is like to hear , or the qualitative or phenomenal nature of sound.

These qualitative features of experience are generally referred to as qualia. If Harpo learns something new, he did not know everything before. He knew all the physical facts before.

So what he learns on coming to hear — the facts about the nature of experience or the nature of qualia — are non-physical. This establishes at least a state or property dualism.

See Jackson ; Robinson There are at least two lines of response to this popular but controversial argument. This essentially behaviouristic account is exactly what the intuition behind the argument is meant to overthrow. Such appeals to intuition are always, of course, open to denial by those who claim not to share the intuition. Some ability theorists seem to blur the distinction between knowing what something is like and knowing how to do something, by saying that the ability Harpo acquires is to imagine or remember the nature of sound.

In this case, what he acquires the ability to do involves the representation to himself of what the thing is like. But this conception of representing to oneself, especially in the form of imagination, seems sufficiently close to producing in oneself something very like a sensory experience that it only defers the problem: until one has a physicalist gloss on what constitutes such representations as those involved in conscious memory and imagination, no progress has been made.

Rather, it is new way of grasping something that he already knew. Demonstrative concepts pick something out without saying anything extra about it. Similarly, the scientific knowledge that Harpo originally possessed did not enable him to anticipate what it would be like to re-express some parts of that knowledge using the demonstrative concepts that only experience can give one. The knowledge, therefore, appears to be genuinely new, whereas only the mode of conceiving it is novel.

Furthermore, experiencing does not seem to consist simply in exercising a particular kind of concept, demonstrative or not. When Harpo has his new form of experience, he does not simply exercise a new concept; he also grasps something new — the phenomenal quality — with that concept. How decisive these considerations are, remains controversial. I said above that predicate dualism might seem to have no ontological consequences, because it is concerned only with the different way things can be described within the contexts of the different sciences, not with any real difference in the things themselves.

This, however, can be disputed. The argument from predicate to property dualism moves in two steps, both controversial. The first claims that the irreducible special sciences, which are the sources of irreducible predicates, are not wholly objective in the way that physics is, but depend for their subject matter upon interest-relative perspectives on the world. This means that they, and the predicates special to them, depend on the existence of minds and mental states, for only minds have interest-relative perspectives.

The second claim is that psychology — the science of the mental — is itself an irreducible special science, and so it, too, presupposes the existence of the mental. Mental predicates therefore presuppose the mentality that creates them: mentality cannot consist simply in the applicability of the predicates themselves. First, let us consider the claim that the special sciences are not fully objective, but are interest-relative.

A mass of matter could be characterized as a hurricane, or as a collection of chemical elements, or as mass of sub-atomic particles, and there be only the one mass of matter.

But such different explanatory frameworks seem to presuppose different perspectives on that subject matter. This is where basic physics, and perhaps those sciences reducible to basic physics, differ from irreducible special sciences.

On a realist construal, the completed physics cuts physical reality up at its ultimate joints: any special science which is nomically strictly reducible to physics also, in virtue of this reduction, it could be argued, cuts reality at its joints, but not at its minutest ones.

If scientific realism is true, a completed physics will tell one how the world is, independently of any special interest or concern: it is just how the world is. It would seem that, by contrast, a science which is not nomically reducible to physics does not take its legitimation from the underlying reality in this direct way.

Rather, such a science is formed from the collaboration between, on the one hand, objective similarities in the world and, on the other, perspectives and interests of those who devise the science.

The concept of hurricane is brought to bear from the perspective of creatures concerned about the weather.