Property Dualism Flashcards
Property dualism theory
Property dualism is the view that, although there is just one kind of substance, physical substance, at least some mental properties are not physical properties (as type identity theory claims) nor functional properties (as functionalism claims), nor are they behavioural dispositions (as philosophical behaviourism claims). Instead, they are properties that do not supervene on physical properties in the way that physicalism claims. While mental properties are possessed by physical substances, they are a fundamentally different kind of property from physical properties.
Property dualism most often defends this claim for phenomenal properties of consciousness. Consciousness, especially the sort of consciousness involved in perception, sensation and emotion, has a ‘feel’ to it, a distinctive ‘experiential quality’. The phrase often used to try to capture this experiential quality is ‘what it is like’. There is something it is like to taste beer, to see a red rose, to feel sad. These properties can’t be reduced to physical, behavioural or functional properties. These properties, at least, are a completely new type of property. (For more on phenomenal properties, see the handout ‘What do we mean by mind?’.)
Rejects physicalism
Property dualism rejects physicalism, and claims that there are some mental properties that exist that are neither physical nor do they supervene on physical properties. It argues that the properties identified by physics do not form the complete fundamental nature of the universe, because in addition, there are properties of consciousness. Physics misses something fundamental. When all the physical properties of the world are finalised, this does not fix or determine the properties of consciousness the way distributing paint on a canvas determines its aesthetic properties.
Property dualists are happy to allow that there may be correlations, even natural (though not physical) laws, that connect particular physical and mental properties. So it may be a law of nature that when a creature has a certain neurological property, it has a certain conscious experience. But it is metaphysically possible for these correlations to be different, for the properties of consciousness to come apart from any physical properties with which they are correlated. Mental properties are an entirely new kind of property in the world, and do not supervene on physical properties in the way that physicalism claims.
Some property dualists argue that these mental properties have their own causal powers, which can affect physical events. This is a second way in which property dualism may reject physicalism, in rejecting physicalism’s claim that non-physical causes do not contribute to the way the physical world changes over time.
The ‘philosophical zombies’ argument for property dualism (David Chalmers).
Property dualism claims that phenomenal properties (which many property dualists claim are qualia) are not physical properties, nor do they supervene on physical properties. It rejects physicalism. But how can a property dualist show this? In ‘Consciousness and its place in nature’, David Chalmers uses the idea of possible worlds to make the argument.
According to physicalism, everything that exists is either physical or depends on what is physical. So if physicalism is true, a possible world that is an exact physical duplicate of our world (the actual world) will be an exact duplicate of our world in all respects. This is just the claim of supervenience, but at the level of the world. Consider: a painting that is an exact physical duplicate of another painting has all the same aesthetic properties as that painting. So a whole world that is an exact physical duplicate of another world also has all the same aesthetic properties. But what goes for aesthetic properties goes for all properties, according to physicalism. There can be no difference in, say, mental properties without a difference in physical properties. In other words, it is metaphysically impossible, says physicalism, for two worlds to have the same physical properties and different mental properties, because the physical properties determine the mental properties.
Therefore, if there is a possible world that is an exact physical duplicate of our world but is different in any way, e.g. it has different phenomenal properties, then physicalism is false. If two physically identical worlds have different properties of consciousness, those properties of consciousness don’t depend on physical properties. This is what Chalmers tries to show with the idea of a philosophical zombie.
Chalmers Zombie arg
First, it seems that zombies are at least conceivable. I’ve just described them, and there isn’t an obvious contradiction in the idea. Second, given their conceivability, we may argue that zombies are therefore metaphysically possible. There is a possible world which has all the same physical properties as the actual world, but has no properties of consciousness.
Now, if consciousness were identical with physical properties, it would be impossible for a creature to have the same physical properties as you but not have consciousness. This is Leibniz’s principle of the indiscernibility of identicals. As we saw with water and H2O, if A is identical to B – if A is B – then you can’t have A without B or vice versa; they are the same thing. So if zombies are possible – if a creature could be physically identical to you but not have consciousness – then consciousness is not identical to any physical properties. So, if zombies are metaphysically possible, then consciousness is not identical to any physical properties. Furthermore, if zombies are metaphysically possible, consciousness doesn’t supervene on physical properties either, because you and your zombie ‘twin’ have identical physical properties, but different phenomenal properties. And so property dualism is true: phenomenal properties are neither reducible to nor supervenient upon physical properties.
Chalmers arg-formal arg
P1.It is conceivable that there are zombies.
P2.If it is conceivable that there are zombies, it is metaphysically possible that there are zombies.
C1. Therefore, it is metaphysically possible that there are zombies.
P3.If it is metaphysically possible that there are zombies, then phenomenal properties of consciousness are neither physical properties nor supervene on physical properties.
C2. Therefore, phenomenal properties of consciousness are neither physical properties nor supervene on physical properties.
C3.Therefore, physicalism is false and property dualism is true.
Property dualism objection
Epiphenomenalist property dualism
If the knowledge and zombie arguments work, then property dualism is true, it seems. On the other hand, Chalmers argues, the claims of physicalism that physical laws govern all events in space-time and that every physical event has a sufficient physical cause seem appealing in light of the success of empirical science. Epiphenomenal property dualism allows both sets of claims to be true. Some mental properties are neither physical nor supervenient on physical properties, but they don’t make any causal difference to the world. Physicalism is right about causation, it just isn’t right about what exists.
The phenomenology of our mental life
We can object, however, that epiphenomenalism is very counter-intuitive. It is part of our experience of having mental states that our mental states, e.g. feeling pain or wanting chocolate or believing that Paris is the capital of France, cause other mental and physical states and events. Most obviously, mental states can cause our behaviour, such as wincing or going to the food cupboard, and they can be part of a causal mental process, such as thinking about how to get to Paris. The ‘phenomenology of our mental life’ involves experience of such causal connections, doesn’t it?
The epiphenomenalist property dualist replies first, that it is only those mental properties that they are dualist about that are epiphenomenal. So, for Chalmers, it is only phenomenal properties of consciousness that are epiphenomenal. We can say that beliefs and desires have causal powers, since we can analyse these states in terms of physical properties and functions. Nevertheless, that the feeling of pain or longing of love is epiphenomenal is still counter-intuitive. So, second, the epiphenomenalist property dualist offers an alternative explanation of why it seems this way to us, even though such mental properties never cause anything.
The physical process in the brain with which phenomenal properties are correlated causes both the phenomenal property, e.g. the painful experience, and the behaviour which we think is caused by the phenomenal property, e.g. jumping up and down. So the experience and the behaviour are correlated because they are both effects of the same cause. It is this correlation that makes us think that the experience causes the behaviour. But it doesn’t.
This may be counter-intuitive, but that is not sufficient reason to reject epiphenomenalism.
Natural selection epiphenomenalist property dualism objection
The property dualist believes that mental properties are properties of physical objects, namely certain living creatures. Suppose that Darwin’s theory of evolution by natural selection is true. According to this theory, millions of genetic alterations randomly take place. Most disappear without a trace. But some that coincidentally help a creature to survive and reproduce slowly spread. That creature and its descendants reproduce more than others without those traits, so more and more creatures end up with them. The features enables the creature to reproduce more, so its descendants also have that feature and they reproduce more and so on.
So, according to the theory of evolution, the traits that evolve over time are ones that causally contribute to the survival and reproduction of the creature. We can assume that mental properties, including qualia, evolved. But how, if they make no difference to what creatures do and so whether they survive and reproduce? Epiphenomenalism conflicts with our best account of the origin of consciousness.
In ‘Epiphenomenal qualia’, Frank Jackson considers this objection and replies that natural selection is more complicated than just described. In fact, there are lots of traits that have evolved that don’t contribute to survival or reproduction, but are instead by-products of traits that do contribute. For instance, polar bears have thick, warm coats which help them survive in the Arctic. A thick coat is a heavy coat. But having a heavy coat doesn’t contribute to the polar bear’s survival, because it makes the bear slower. However, it is better to have a thick, warm and heavy coat than a thin, cool and light coat. Having a heavy coat is a by-product of having a thick, warm coat, and having a thick, warm coat contributes to survival.
Likewise, there are brain processes that make a difference to how a creature behaves and which are very conducive to survival. Consciousness, according to epiphenomenalism, is simply a by-product of these brain processes. It just happens to be a fundamental law of nature that these physical properties are correlated with certain properties of consciousness.
We can object that this response presents us with a very divided picture of the world. Consciousness sits entirely outside the rest of the natural world, and has no effect on it.
Jackson accepts this: we shouldn’t expect to understand the world. Our abilities to understand the world themselves relate to survival. As a result of evolution, we are equipped to learn about and understand what we need to know in order to survive. Consciousness doesn’t make any difference to this, so it is no surprise that we can’t understand it well.
Epiphenomenalist objection introspective self-knowledge
Epiphenomenalism makes it hard to understand how we have knowledge of our own mental states. How do I know that I am in pain when I am? The obvious answer is that my belief that I am in pain is caused by my pain itself. I can tell that I am in pain just from introspection. But if epiphenomenalism is true, pain doesn’t cause anything, even my belief that I am in pain. This threatens a natural account of our knowledge of our mental states. If my thoughts and feelings don’t cause my beliefs about my mind, then I could have those beliefs whatever my mental states, just as long as the causes of my beliefs (whatever they are – perhaps brain processes, perhaps God) operate in the same way. In other words, whatever causes me to belief that I am in pain could cause me to have this belief even when I am not in pain. And so my beliefs about my mind, therefore, are unjustified and unreliable. So I can’t know my own mind.
Epiphenomenalists can reply that knowledge of something doesn’t always require that thing to cause one’s belief. I can know that I am in pain without the painful experience causing this knowledge. For instance, suppose the brain state that my belief that I am in pain is also the same brain state that causes my pain. In this case, I wouldn’t, under normal circumstances, have the belief that I am in pain unless I was in pain – the same brain state causes both. So even though my belief that I am in pain isn’t caused by the painful experience, I can know that I am in pain because my belief is caused by a reliable mechanism.
Chalmers gives a different response. Knowledge of my experiences is knowledge by acquaintance. I am directly aware of my experiences, but this is not a causal relation. My belief that I am in pain is partly constituted, not caused, by this direct awareness. My being in pain makes my belief the belief that it is. So my knowledge that I am in pain depends on my being in pain, but is not caused by it.
Issues facing dualism- category mistake
Gilbert Ryle calls substance dualism ‘the dogma of the Ghost in the Machine’. The mistake that it makes, he argues, is a ‘category mistake’. What does that mean? Suppose someone is shown around Oxford University – they see the colleges, the buildings with the different faculties and departments, the administrative buildings. But then they ask, ‘I’ve seen the colleges, the faculties, the administration. But where is the university?’ They have misunderstood the concept of ‘university’, thinking that the university is another thing, alongside the colleges, faculties and administration. The person has made a category mistake. The university is not like this; it is how everything that the person has seen is organised.
Concepts belong to different logical categories – different ways in which it makes sense to use a concept. A category mistake is to treat a concept as belonging to a different logical category from the one it actually belongs to. According to Ryle, substance dualism makes the category mistake of thinking that the mind is like the body – another ‘thing’, a distinct, complex, organised unit subject to distinct relations of cause and effect. The mistake is to think that physical and mental concepts operate in the same way, in the same logical framework of ‘things’ and ‘causes’, ‘substances’ and ‘properties’.
We can apply his objection just as easily to property dualism. While property dualism doesn’t claim that the mind is a distinct substance, it does think of mental properties – or at least phenomenal properties of consciousness – as part of the same metaphysical framework as physical and functional properties, only not physical.
Ryle would argue that the concept of phenomenal properties (let alone qualia) misunderstands our talk of sensations, feelings, images, and so on. These are not each a ‘something’ that has peculiar properties of ‘what it is like’. The whole metaphysical picture here is wrong.
So how should we understand our talk about conscious experiences? On Ryle’s behalf, we could argue that when we express our experiences, we use words that derive their meaning from describing physical objects. To say ‘what it is like’ to see red is simply to describe what we see when attending to the colour of a red object, or if it is not in front of us, we give a report of our memory of seeing it. The redness that we experience is the redness of the rose, not a property of our experience of it.
People don’t normally talk about ‘sensations’ or ‘what it is like’ in the sense of qualia in everyday language, before being exposed to some theory. If you ask someone ‘what it is like’ to see a rose, they will usually respond evaluatively, e.g. ‘it’s wonderful’ or ‘it’s calming’. Of course, experiences differ from each other. But this isn’t because what each experience ‘is like’ differs. We can express the difference between what experiences ‘are like’ in terms of what the experience is of (red roses look different from yellow roses – this is a difference between roses, not between experiences of roses), and how we evaluate experiences, e.g. whether we enjoy one and find another boring. The property dualist has misunderstood our mental concepts.
For example, in response to the knowledge argument, what we should say is this. In knowing all the physical facts, Mary can’t yet understand our normal way of talking about experiences. She has no experiences of coloured objects that she can express and report, and as a result, she has only a limited understanding of our discussions of them. But none of this has to do with knowledge of facts, either facts about some ‘inner’ conscious experience or facts about the brain. To think otherwise is a category mistake.
The knowledge arg
THE KNOWLEDGE ARGUMENT
In ‘Epiphenomenal qualia’, Frank Jackson defends property dualism on the basis of his ‘knowledge argument’. He describes the following scenario. Suppose there is a neuroscientist, Mary, who has lived all her life in a room in which everything is black and white. She has never seen any colour other than black, white and shades of grey. However, she has specialised in the science of vision, and through textbooks and black-and-white TV, she has come to know every physical fact there is to know about colour vision – everything about the properties of light, everything about the eye, everything about the nerves and the brain related to vision. So, Mary knows all the physical information there is to know about what happens when we see a ripe tomato. She is then let out of the black-and-white room, and comes to see something red for the first time. Does she learn something new?
Jackson claims that ‘it seems just obvious’ that she will. She will learn about what it is like to see the colour red. And so she learns something new about our visual experience of the world. However, we said that she knew all the physical facts while she was in the room. So not all the facts are physical facts. It is possible to know all about the physical properties of the brain involved in having an experience and yet not know about the qualia.
Knowledge formal arg
P1.Mary knows all the physical facts about seeing colours before being released from her black-and-white room.
P2.On being released, she learns new facts about seeing colours.
C1.Therefore, not all facts are physical facts, e.g. some facts about colours are not.
C2.Therefore, phenomenal properties are non-physical and physicalism is false.
By ‘all the physical facts’, Jackson means not only what we already know about physics and neurophysiology. Mary knows all the physical facts as discovered by a completed physics and neuroscience. Furthermore, she has worked out all the causal and functional facts that are entailed by these facts. Because physicalism claims that the world is entirely physical (if we include causal and functional properties), it must claim that to have complete physical knowledge is to have complete knowledge. But no amount of physical information can enable Mary to know what it is like to see a ripe tomato.
Responses to the knowledge arg
Physicalist responses to Jackson’s argument point out that there is more than one meaning of ‘to know’, more than one kind of knowledge. We can and should accept that Mary gains new knowledge when she sees red for the first time. But this doesn’t mean that she gains knowledge of some new fact. We will look at three different responses offering alternative accounts of just what Mary learns.
Mary does not gain new propositional knowledge, but does gain ability knowledge
The first response argues that instead of gaining knowledge of a fact, described by a proposition (e.g. ‘that red looks like this’), Mary gains know-how – the knowledge involved in certain abilities. For instance, to see red for the first time is to gain the ability to know how to imagine or recognise red. So Jackson hasn’t shown that there are any facts that are not physical facts.
We can challenge this objection as follows. Suppose that seeing red gives us these new abilities. Are such abilities all that is involved in knowing what it is like to see red? Suppose Mary wonders whether what it is like for others to see red is the same as what it is like for her. She isn’t wondering about her abilities to imagine and recognise red. She is wondering about the truth of a proposition. So when Mary first learns what it is like to see red, she does gain knowledge of a new fact.
Is the objection even right to think that knowing what it is like to see red involves knowing how to imagine red? Suppose there is someone who (for whatever reason) has no ability to imagine seeing red. Now suppose this person looks attentively at something red. While they look at red, they know what is it like to see red. And yet they cannot imagine seeing red. This shows that the ability to imagine is not necessary for knowing what it is like to see red. Now suppose someone else has the most amazing ability to imagine seeing colours. They are told that there is a shade of red, e.g. burgundy, that is between plum red and tomato red. They are now able to imagine burgundy, but as long as they don’t actually imagine burgundy, they still don’t know what it is like to see burgundy. This shows that the ability to imagine a colour is not sufficient to know what it is like to see it. (We can make similar arguments for recognising colours.)
If the ability to imagine seeing red is neither necessary nor sufficient for knowing what it is like to see red, then when Mary comes to know what it is like to see red, she learns more than simply knowing how to imagine seeing red. The response fails to show that Mary does not learn a new fact. It fails to show that the knowledge argument is mistaken.
Mary does not gain new propositional knowledge, but does gain acquaintance knowledge
A second response to Jackson’s argument argues that Mary gains a different kind of knowledge again, not propositional knowledge (knowing that), but not ability knowledge (knowing how) either. Instead, she gains ‘acquaintance knowledge’ – knowledge given by direct awareness of something in experience, e.g. a person, a place, or one’s own thoughts and feelings.To see red is a direct apprehension of red, as contrasted with descriptions of seeing red. How does the objection work?
Suppose that what it is like to see red is a physical property of the visual experience, which itself is a physical process. In other words, the phenomenal property of what it is like to see red is some property of the brain (type identity). Mary can then know all about this physical property, about what it is, when it occurs, and so on, before she leaves the room. However, she is not acquainted with the property – she doesn’t have direct knowledge of it because her brain has never itself had this property. When she sees red, this property occurs in her brain and she becomes acquainted with it. She gains new knowledge, but she hasn’t learned any new fact. She already knew all about this property before she left the room. (Compare: a friend describes someone you have never met. When you first meet the person and become acquainted with them, you think of them in a new way. But the person you meet was someone you already knew about.)
In Brainwise, Patricia Churchland puts the two responses together. Knowing the neuroscience won’t help you experience or identify phenomenal properties in consciousness. For this, the theory needs to be true of your brain, i.e. your brain needs to undergo the processes that the theory describes as constituting colour experience. This fact doesn’t mean that there is something that the theory misses out. When Mary’s brain actually undergoes the processes that she knows all about, then she will be acquainted with colour and gain abilities of recognition etc. But that is all the colour experience is. Nothing in addition to the physical processes is needed or occurs.
There are two possible responses to this objection. First, we can argue that acquaintance knowledge involves propositional knowledge. What it is to be acquainted with red is to know that seeing red is like this (having the experience). Becoming acquainted with red involves learning some new fact. So Mary does learn a new, and therefore non-physical, fact when she becomes acquainted with red. So what it is like to experience red can’t simply be a physical property of the brain.
Second, we can argue that the objection misunderstands the argument. The knowledge argument isn’t about Mary’s experience. The argument is that Mary didn’t know everything about other people’s experiences before she left the room, even though she knew everything physical about their experiences. Mary doesn’t know what it is like for anyone to experience red. This is a fact about experiences that Mary doesn’t know. When Mary leaves the room, she realises how impoverished her conception of people’s colour experiences has been. So there are facts about other people’s experiences of seeing red that Mary learns.
