Descartes

1. Meditations II & VI: Descartes’ Dualist Ontology Descartes Meditation I

2. Descartes Ontology From epistemology to ontology: discovering the essences of things

3. What is there? • Ontology: The study of what there is fundamentally--what entities or kinds of entity exist? • Abstracta: not spatio-temporal, not causally efficacious • Are there abstract entities, such as sets or numbers, in addition to concrete entities, such as people and puddles and protons? • Are there properties or universals in addition to (or instead of) the particular entities that, as we say, instantiate them? • Concrete objects • Material things? • Immaterial things?

4. Descartes’ Quest for Essence • Descartes ontological question: what is the most fundamental way of classifying objects--what are the most fundamental kinds or categories to which a thing can belong and • What is essential to being a member of one of those fundamental kinds, i.e. what properties do objects of that kind necessarily have. • Descartes argues that the most fundamental kinds are • Spiritual substance • Essence - thinking: established by reflection on what he knows for certain about himself • Material substance - essence: extension • Essence - extension: established by the Wax Example

5. Essence, Existence, and Change • Essential vs. Accidental Properties: P is an essential property of an object o just in case it is necessary that o has P, whereas P is an accidental property of an object o just in case o has P but it is possible that o lacks P. • A property is essential to a thing in virtue of the kind to which it belongs • A thing of a kind K has the properties essential to being a Knecessarily: if it didn’t have those properties it wouldn’t exist. • If a thing of a kind K loses a a property essential to being a K it ceases to exist. • Example: a table continues to exist when it loses accidental properties, e.g. when painted a different color but ceases to exist if it loses properties essential to being a table as, e.g. when burnt so a pile of ashes of ground up to leave a mound of saw dust.

6. From Epistemology to Ontology • Descartes argues for these conclusions via two thought experiments to sort out accidental from essential properties • I (a person) am essentially thinking substance • I can conceive of myself without having the properties of a body so these are accidental but not without thinking so thinking is essential to me. • Material things (if there are such) are essentially extended substance • Taking a piece of wax as a sample material object , I can conceive of it losing color, smell, etc. so these are essential properties but not without it being extended, i.e. space-occupying, so that’s an essential property. • Assumption: a property is essential an object if and only if the object and property are inseparable in though--if I can’t conceive one without the other.

8. What do I know? • Foundationalism: rebuilding from foundation of certainty (the Archimedian point) • ‘I will set aside anything that admits of the slightest doubt’ (for the time being) including • The existence of ordinary material objects (including my own body) and their properties (‘Body, shape, extension, movement, place) since sense experience is unreliable • What is certain? (i.e. Evil-Demon-Resistent?) • Cogito: I know that I exist (‘let him [the demon] deceive me all he can, he will never bring it about that I am nothing while I think I am something • ‘I am simply a thing that thinks--a mind, or soul, or intellect, or reason’

9. The Archimedian Point! Archeimedes said that if he had one firm and immovable point he could lift the world with a long enough lever; so I to can hope for great things if I manage to find just one little thing a that is solid and certain.

10. I am! I exist! • ‘I must finally conclude that this proposition, I am, I exist, is necessarily true whenever it is put forward by me or conceived in my mind.’ • First person formulation essential: I only know of my own existence. • Present tense formulation essential: I only know that I now exist • My existence is not necessary but necessarily if/when I conceive or doubt my existence I exist. • Does not assume ontological dualism or doctrine of the substantial self (to be discussed later): I don’t know what I am. • Arguably assumes point-or-view--which isn’t given in sense-experience (as Hume notes). Do I know that I exist rather than just that thinking occurs?

11. Argument: I know that I exist! • Argument: I can be certain of my own existence • If I know that thinking occurs then I know that I exist. • I know thinking occurs. • Therefore, I know that I exist • Questions: • Does knowing that thinking occurs imply that there’s something doing the thinking? Can ‘thinking occurs’ be like ‘It’s raining’ which doesn’t imply that there’s some object doing the raining? Can there be free-floating thoughts? • Do I know that thinking occurs? Even if, necessarily, whenever I think of myself it’s true that I’m thinking, does it follow that I even believe that I’m thinking? Is that demon-resistent?

12. Privileged Access • ‘I know plainly that I can achieve an easier and more evident perception of my own mind than of anything else.’ • Further questions on varieties of privileged access of the mental: • Omniscience: if I am in a mental state, S, then I believe I’m in S. (I can’t be ignorant) • Infallibility: If I believe that I’m in a mental state, S, then I am in S. (I can’t be mistaken) • And many other varieties, e.g. I know better than anyone else whether I’m in S • Varieties of mental states--’feely’ and otherwise…

13. The Subconscious? What do I know of myself?

14. I am essentially a thing that thinks • I am, I exist--that is certain. But for how long? For as long as I am thinking…What is that? A thing that doubts, understands, affirms, denies. • I can’t conceive of (i.e. think of) myself without conceiving of a thing that thinks because when I think of myself what I conceive of is a thing that’s thinking. • I can’t coherently doubt or deny that I’m thinking because doubting and denying are themselves thinkings. • What’s inconceivable is impossible so not possible that I don’t think, i.e. necessarily I exist only if I think--thinking is essential to me. • Something funny going on here: compare to Berkeley’s Master Argument: it’s unthinkable that things exist unperceived therefore necessarily they exist only if perceived--their esse is percipi.

15. Argument: thinking alone is essential to me • If I know that I exist then I know that I think. • It is not the case that if I know that I exist I know that I have any other property • A property, P, is essential to being a thing of a kind K if and only if having P is inseparable in thought from being K, i.e. if and only if I can’t conceive of a Knot having P. • I can’t conceive of myself not thinking. • I can conceive of myself not having any property other than thinking • Thinking is essential to me and no other property is essential to me • Problem: Is 3 true? Is conceivability a criterion for possibility so that if I can’t conceive of a K not having P then Ks necessarily have P (i.e. not possible for a K not to have P?

16. Is having a body an accidental property? • Recall: P is an essential property of an object o just in case it is necessary that o has P--o couldn’t exist if it didn’t have P • Does conceivability/inconceivability deliver the right kind of necessity? • Water is essentially H2O: necessarily water is H2O • There’s no possible world at which there’s water that’s not H2O • It’s not metaphysically possible that water not be H2O • But I can conceive of water without conceiving of it as H2O--people have known what water was, have been able to identify it, without knowing that it was H2O. • So, if I can conceive of myself not having a body, arguably, it doesn’t follow that having a body is an accidental property--it might be essential to me without my knowing it

17. Is thinking an essential property? • I can’t conceive of myself not thinking--or can I? • Whenever I conceive of myself what I conceive of is thinking (since conceiving is itself thinking) • But it doesn’t follow that what I conceive of couldn’t exist without its thinking. • Compare to Berkeley’s argument that since unthought-about objects are inconceivable they cannot exist apart from being throught-about: I can’t conceive of an object that’s unthought-about when I conceive of it since at any time I conceive of it it’s an unthought-about object BUT… • When I conceive of myself what I conceive of at that time is thinking BUT…this doesn’t establish that I cannot exist without thinking

18. Now what? I think,therefore I am

19. The Wax Argument

20. The Wax Thought Experiment • Preliminary: what is a thought experiment--and what can a thought experiment show? • Distinguish sense perception and judgement (compare judgement re optical illusions!) • We say that we see the wax itself, if it is there before us, not that we judge it to be there from its colour or shape; and this might lead me to conclude without more ado that knowledge of the wax comes from what the eye sees, and not from the scrutiny of the mind alone. • But then if I look out of the window and see men crossing the square, as I just happen to have done, I normally say that I see the men themselves, just as I say that I see the wax. Yet do I see any more than hats and coats which could conceal automatons? • I judge that they are men. (Intellect entertains; will judges)

21. Material objects are essentially extended • A property, P, is essential to a thing if that thing can’t lose that property without ceasing to exist • Contrapositively, if a thing can lose a property without ceasing to exist then it isn’t an essential property of the thing, i.e. is an accidental property. • The wax is a sample material object: we’ll consider what properties it can and can’t lose without ceasing to exist in order to determine which properties are essential and which accidental. • I see that the wax could lose sensible properties yet still be the same wax but understand by reason (Descartes is a rationalist) that what makes it the same wax throughout the story is spatio-temporal continuity. • Same for all material objects so I conclude that extension is essential to material objects.

22. Descartes Rationalism • Mind's immediate perception does not, strictly speaking, extend beyond itself, to external bodies. …an important basis of the mind-better-known-than-body doctrine. • But I shall let my mind run free for a while and consider what material substance would be like if it were out there… • The sensible qualities of the wax (taste, smell, color, tangible solidity, etc. are like the hats and coats on the men in the street--which don’t show what they are. • Even bodies are not strictly [proprie] perceived by the senses or the faculty of imagination but by the intellect alone, and that this perception derives not from their being touched or seen but from their being understood.

23. So, what is there? • Me…at least me now...or at least my current thoughts (e.g. my thinking, my doubting, etc. • But I still don’t know what I am other than that I am a thing that thinks (that has to wait until Meditation VI) • I know also that if there are material things out there (which I don’t yet know) then they are essentially extended substances. • So...I am a thinking thing; material things if there are such are extended substances. • But am I, this thinking thing, the Archemedian point from which I can leverage further knowledge about about the world???

24. Now what?

25. The Mind-Body Problem What is the relationship between mental properties and physical properties?

26. Meditation VI: The Program • Digging out of skepticism • I will go back over everything that I believed true before doubting • I will rehearse my reasons for doubting • I will dig myself out of skepticism • Cartesian Dualism • Mind and body are distinct and can exist independently • Mind is a substance • The self is mind: ’my mind is me’ • Mind and body interact

27. Some Questions • Are mind and body distinct?: 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? Why reject physicalism--the intuitive view that that we’re just physical things: brains, parts of brains, or living organisms in toto? • Descartes argument for mind-body dualism • The ‘hard problem of consciousness’ • Is mind a substance? Or a bundle of events/states? • The problem of the self: what is the self? Related to this (and coming up): the Problem of Personal Identity • Do mind and body interact? If so, how?

28. The Self: Bundle Theories and Substance Theories • Substance: Something that has properties. Not a property or bundle of properties or “mode” or arrangement • Is the self a substance or a bundle of psychological states? • Property Dualism vs. Substance Dualism • Substance (“Cartesian”) Dualism: the self is an immaterial substance. • Property Dualism: the self is not an immaterial substance but either • a bundle of immaterial states/events • a material thing (e.g. a living organism) that has mental states

29. Mind as a Substance • I can vividly and clearly understand myself as a whole without these faculties [of imagination, sensory perception, etc.]; but I can’t understand them without me, that is, without an intellectual substance for them to belong to…so I see that I differ from my faculties as a thing differs from its properties. • Descartes conceivability argument for a substance theory: is the analogy between self and its actions and objects and their properties any good? Can’t I conceive of a property uninstantiated? What, if anything does conceivability show anyway? • Can I even conceive of myself apart from actions and ideas? (Hume) • Or do I have some ‘notion’ of self, or require it to make sense of integrating experiences?

30. My mind is me • Compare Aristotelian/Thomistic account of persons as composites, mind as ‘form’ of the body. • Problem of personal-identity ‘through time’ • Even assuming that at any given time there is no more to a person than a spiritual substance, could different spiritual substances at different times be the same person. • Locke argues that could be • Necessity of Identity: if x and y are identical then necessarily identical so one thing can’t be identical to different things at different times. • On this account while I am at any time constituted by a spiritual substance I am not identical to it.

31. Mind-Body Interaction • Princess Elizabeth’s question: how can mind and body interact • The Old Problem: causation is mechanical--billiard balls bumping into billiard balls. So how can mind, which is not spatial interact with body, which is? • The New Problem: the closure of the physical. Every physical effect that has a sufficient cause has a sufficient physical cause. Every physical event can be explained wholly in terms of physical events, states, and physical laws. • Bodily actions therefore can be completely explained in physical terms. • Mental events aren’t needed to explain people’s behavior. • Mental causes are an extra so should be dismissed. Compare Ryle’s story of the peasants and the steam engine. (Isn’t there really a horse inside?)

32. Dualisms • Interactionism Problems: how interact & closure of the physical • Epiphenomenalist Problem: mental states are idle • Parallelism Problem: God gotta wind up the two clocks. Occasionalism also bad.

33. Dualist Theories of Mind • Predicate Dualism: psychological or mentalistic predicates are (a) essential for a full description of the world and (b) are not reducible to physicalistic predicates. • Compare to functional terms, e.g. hurricane.: irreducibly different in type but token identity between each individual hurricane and a mass of atoms. • Property Dualism: There are two essentially different kinds of properties in the world • Substance (“Cartesian”) Dualism: mental substance is distinct from material substance • Substance: the thing which possesses properties. • For substance dualists not only the properties but the substance that has them is immaterial

34. Physicalism: Isn’t it obvious? Not as obvious as you think--some arguments for dualism Cartesian and otherwise

35. Physicalism • The thesis that everything is physical, a.k.a materialism • A complete physics will explain all facts about the world • Physicalism is true at a possible world wiff any world which is a physical duplicate of w is a duplicate of w simpliciter. • Physicalism is usually taken to be a matter of contingent fact • There are worlds at which there are non-physical facts but (according to physicalists) ours isn’t one of them. • Psychological or biological or social features of the world supervene on physical facts about the world.

36. Supervenience • What these hedges are like at the leaf-and-branch level determines what the topiary looks like. • But hedges that were different at the leaf-and-branch level could have the same topiary look

37. Supervenience • A dot-matrix picture has global properties … yet all there is to the picture is dots and non-dots at each point of the matrix. The global properties are nothing but patterns in the dots. no two pictures could differ in their global properties without differing, somewhere, in whether there is or there isn't a dot.[David Lewis] • Same base properties then same supervenient properties but not vice versa. • More examples: • Moral properties supervene upon non-moral properties. • Dispositions supervene upon their ‘categorical bases’.

38. Physicalism: Pro • Closure of the physical • Even if we can’t currently explain everything in physical terms, physicalism in an aggressor hypothesis. e.g. explaining life in naturalistic terms • The reducibility of psychological, biological and other explanations to physical explanations • The elimination of irreducible agency explanations: agency explained in terms of physical causation

39. Against Physicalism • Descartes’ argument from clear and distinct conceivability • The fact that I can vividly and clearly think of one thing apart from another assures me that the two things are distinct from one another (and can exist independently--allows for post-mortem survival and free will in a deterministic physical universe. • Descartes’ argument from different properties: x = y only if they have exactly the same properties. • Bodies are essentially extended and have parts; minds are not extended and don’t have parts. • Contemporary argument for some kind of dualism--at least dualism of properties: the ‘hard problem of consciousness’

40. Physicalism: Con QUALIA!

41. Consciousness: The Hard Problem Knowing what it’s like

42. Broad’s Archangel He would know exactly what the microscopic structure of ammonia must be; but he would be totally unable to predict that a substance with this structure must smell as ammonia does when it gets into the human nose…[H]e could not possibly know that these changes would be accompanied by theappearance of a smell in generalor of the peculiar smell ofammonia in particular, unlesssomeone told him so or he hadsmelled it for himself. NH3

43. Feigl’s Martian Could a Martian, entirely without sentiments of compassion and piety, know about what is going on during a commemoration of the armistice?…[He could] predict all responses, including the linguistic utterances of the earthlings in the situations which involve their visual perceptions, their laughter about jokes, or their (solemn) behavior at the commemoration. But ex hypothesi, the Martian would be lacking completely in the sort of imagery and empathy which depends on familiarity (direct acquaintance) with the kinds of qualia to be imaged or empathized

44. What It’s Like • Qualia: the introspectively accessible, phenomenal aspects of our mental lives Thomas Nagel in “What It Is Like to Be a Bat” argues that some facts can only be captured ‘from a subjective perspective’ and uses his example of bats to illustrate the point Even if we knew everything there is to know ‘from an objective perspective’ about a bat's sonar system we still would not know ‘what it is like’ to perceive a given object with a bat's sonar system.

45. Mary and the Zombies An argument for property dualism

46. Philosophical Zombies

47. The Zombie Argument • A (philosophical) zombie is a being which is a perfect duplicate of a normal human being—including brain and neural activity—but which is not conscious. • The Zombie Argument for property dualism • Zombies are conceivable • Whatever is conceivable is logically possible • Therefore (some) mental states/properties/events are not identical to any brain states/properties/events • Note: this argument doesn’t purport to establish substance dualism or, as Descartes wished to show, that minds/persons could exist in a disembodied state!

48. The Knowledge Argument From Frank Jackson. ‘What Mary Didn’t Know’

49. What Mary doesn’t know • Mary is a brilliant scientist who is…forced to investigate the world from a black and white room via a black and white television monitor. She specializes in the neurophysiology of vision and acquires…all the physical information there is to obtain about what goes on when we see ripe tomatoes…and use terms like ‘red’… • Mary is confined to a black-and-white room, is educated through black-and-white books and through lectures relayed on black and white television…She knows all the physical facts about us and our environment, in a wide sense of ‘physical’ which includes everything in completed physics, chemistry, and neurophysiology, and all there is to know about the causal and relational facts consequent upon all this, including of course functional roles.

50. If physicalism is true, she knows all there is to know. To suppose otherwise, assumes that there is more to know than every physical fact, and that is just what physicalism denies.