This week’s aims  To test your understanding of substance dualism through an initial assessment task  To explain and analyse the philosophical zombies and knowledge (Mary) arguments for property dualism

The indivisibility argument

The conceivability argument

5-mark questions  Briefly outline Descartes’ indivisibility argument (5 marks)  Briefly outline the conceivability argument for substance dualism (5 marks)

Mark scheme

Sample answers to 3-mark and 5-mark questions  What are qualia? (3 marks)  What is substance dualism? (3 marks)  What is property dualism? (3 marks)  Briefly outline Descartes’ indivisibility argument (5 marks)  Briefly outline the conceivability argument for substance dualism (5 marks)

Initial Assessment – 20 minutes  Define:  Mind-body problem  Qualia  Substance dualism  The indivisibility argument  The conceivability argument  How convincing are Descartes’ arguments for substance dualism?

Initial assessment  There were two marks available for each definition question  There were ten marks available for the discussion question  Did you include your own ideas / arguments? If you only listed the views philosophers without debating them, you won’t have got more than seven marks – it’s really important to say what YOU think  A*=18, A=16, B=14, C=12, D=10, E=8

Property Dualism

What is property dualism?

 Property dualism accepts only that there are physical and mental properties – it doesn’t accept that there are physical and non-physical substances.  This means that although mental properties do exist and cannot be accounted for in terms of physical properties, substances are purely physical.  In claiming this, property dualism is actually a form of monism – it claims that only one kind of substance exists.  But (unlike type-identity theory) it is also non-reductive, which means that according to property dualism mental properties are not identical with physical properties and cannot be reduced to them.

Task – 20 minutes  Groups 1&2: Explain the philosophical zombies argument and how it illustrates property dualism  Groups 3&4: Explain the knowledge / Mary argument and how it illustrates property dualism

5 mark questions  Briefly explain the philosophical zombie argument for property dualism (5 marks)  Briefly outline the ‘knowledge’ / Mary argument for property dualism (5 marks)

Philosophical zombies

What does Chalmers argue?  It is conceivable and therefore metaphysically possible for there to be a creature which is physically identical to you, and yet is totally devoid of conscious experience.  If philosophical zombies are metaphysically possible then materialism is false because it fails to recognise the existence and importance of mental properties (qualia).  The possibility of zombies means that facts about qualia are additional to the possession of physical properties – if a creature could have all those physical properties and yet lack qualia, then to have mental states involving qualia is something more than just having those physical properties.  So the mind is not merely the body or the brain, but something additional to them.

Problems with Chalmers’ ideas  A ‘zombie’ world is not conceivable  The first objection to the argument is that, despite appearances, zombies are not conceivable.  If we think they are conceivable, we are not thinking clearly or we lack some relevant information.  It is difficult to recognise that we are not thinking clearly. But we can spell out where we are going wrong in more detail:  First, if physicalism is true, something’s physical properties determine its functional properties. So a physical duplicate of you should also be a functional duplicate of you, and property dualism fails to recognise this.

Problems with Chalmers’ ideas  Second, our understanding of consciousness is still underdeveloped.  It may seem that qualia distinguish physical and mental properties, but if we understood consciousness more fully we would see that it can be completely explained in physical terms.  In that case, a physical, functional duplicate of you would also have consciousness. So to imagine a being with identical physical properties to you but without consciousness is confused. It is like accepting the premises of a deductive argument but rejecting the conclusion.  In conceiving of a ‘zombie’ as having identical physical properties, you conceive of it as having identical functions. To function in certain highly complex ways is what it means to be conscious.  So zombies – physically identical, but non-conscious beings – are inconceivable.

How convincing is this objection?

Problems with Chalmers’ ideas  What is conceivable is not possible  The fact that we can conceive of zombies doesn’t show that zombies are metaphysically possible.  If phenomenal properties are just certain physical and/or functional properties, then it isn’t possible for zombies to exist.  Given the physical properties we have, if physicalism is true, it just isn’t possible for a being with the same physical properties as us not to have consciousness as well – because consciousness is one of our physical properties.

How convincing is this objection?

Problems with Chalmers’ ideas  What is logically possible tells us nothing about reality  We might perhaps grant the idea that zombies are possible, but can we really infer that property dualism is true simply by showing that it is possible?  The zombie argument shows, at best, that in another possible world, physical properties and phenomenal properties are distinct.  But why does that entail in the actual world, they are distinct?  Couldn’t it be the case that physicalism is true in the actual world, but property dualism is true in a different possible world?

How convincing is this objection?

Knowledge / Mary

What does Jackson argue?  The knowledge argument for property dualism tries to show that knowledge of physical reality does not on its own add up to knowledge of mental reality.  Materialism claims that physical facts are all there are. But Mary, hypothetically, knew all the physical facts there were to know about perception – the sorts of facts that could be written down in neuroscience textbooks or explained in lectures.  Yet she didn’t really know all the facts there were to know about perception – she hadn’t yet learned the non-physical facts that come from actually experiencing qualia.  The knowledge argument therefore claims that phenomenal properties can’t be understood in terms of physical and functional properties. Instead, it understands phenomenal properties as qualia – intrinsic and non-representational properties of experience.

Problems with Jackson’s ideas  Mary gains no new propositional knowledge (but gains acquaintance knowledge or ability knowledge)  Although there is a sense in which Mary learns something new upon leaving the room, what she learns doesn’t really threaten materialism.  Paul Churchland argues that Mary wouldn’t actually learn any new facts – instead she would just learn, in a new way, facts she already knew.  Since she already knew all the physical facts, she gains no new propositional knowledge upon leaving the room.  It is true that she gains acquaintance knowledge – because she now becomes familiar with something that she had previously only theorised about – but this doesn’t mean she has actually learned any new facts.

How convincing is this objection?

Problems with Jackson’s ideas  All physical knowledge would include knowledge of qualia  This objection claims that there is, in principle, a complete analysis of phenomenal properties in physical and functional terms.  If Mary really did know everything about seeing red, she would not learn anything when she first sees red.  The experience of seeing red is nothing more than highly detailed knowledge of what it is to see red, and Mary already has this highly detailed knowledge.

How convincing is this objection?

Problems with Jackson’s ideas  There is more than one way of knowing the same physical fact  Before leaving the room, Mary has a concept of red in physical terms – wavelengths of light, neurons firing, and so on. Call this the ‘physical’ or ‘theoretical’ concept of red.  We can contrast this with a ‘phenomenal’ concept of red. A phenomenal concept of something is the concept by which you recognise something when you experience or perceive it. So we gain the phenomenal concept of red by seeing red.

Problems with Jackson’s ideas  When Mary comes out the room and sees red, she acquires the phenomenal concept of red for the first time. She is now able to think about red in a new way, in terms of what it is like to see red. She couldn’t know what it is like to see red before because she didn’t have the phenomenal concept.  But, we can claim, the phenomenal concept of red is a concept of the same thing that her physical concept is a concept of – they are two different concepts of a physical property of the brain

How convincing is this objection?

Problems with Jackson’s ideas  Qualia (as defined) do not exist and so Mary gains no propositional knowledge  There are no qualia.  Phenomenal properties are, instead, just physical, functional properties.  When we think through carefully just how much knowledge Mary must have in order to know everything about colour experience, is it coherent to say that she won’t know what it is like to see red before she leaves her room?

Problems with Jackson’s ideas  The property dualist has misunderstood our mental concepts.  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

How convincing is this objection?

Moodle  Frank Jackson

Homework  Make a glossary of key terms  Use your textbook to help you:  Clear and distinct ideas  Conceivability argument  Conceivable  Consciousness  Dualism – substance and property  Indivisibility argument  Knowledge / Mary argument  Philosophical zombie argument  Property  Qualia  Sensation  Substance