Tom Nagel
The Mind-Body Problem
1. Question: What is the relationship between consciousness (mind) and the brain (body)?
2. Three answers:
a. Dualism: Two different kinds of things (consciousness/mind is mental stuff and the brain is physical stuff)
b. Physicalism: Identity; they are the same thing (only one kind of thing, physical stuff)
c. Dual aspect theory: They are two different aspects of the same thing (one thing, two properties)
3. Are there implications of physicalism for nature of God and immorality?
4. WHAT WE KNOW/BELIEVE AS A RESULT OF SCIENCE
a. Mind and brain are interdependent
5. We know that what happens in consciousness depends on what happens to the body/brain
a. That somehow your conscious experience is at least in part tied to changes in the body.
b. Examples: Stub your toe, it hurts; Close your eyes, can’t see; Bite into Hershey bar, taste chocolate; If someone conks you on head, you pass out
i. First event happens to your body, second happens to your consciousness
6. For anything to happen in your mind/consciousness, something has to happen in your brain
a. Would not feel pain from toe stub if nerves to brain cut
b. Although we don’t know exactly what it is that happens in your brain when you wonder about getting a haircut
i. We are pretty sure something electrical/chemical changes in the billions of nerve cells in your brain.
c. Questions:
i. Could science show not possible for new event in mind to occur without some change in brain?
ii. This would rule out possibility of some other being or mind putting a thought in your mind w/o affecting your brain.
7. In some cases we do know (roughly) how the brain affects the mind and how the mind affects the brain
a. Stimulation of certain brain cells at back of head produces visual experience
b. When you decide to have another piece of cake, certain other brain cells send out impulses to the muscles in your arm
8. Above is science
9. PHILOSOPHICAL QUESTIONS ABOUT CONSCIOUSNESS/BRAIN
10. Is your mind something different from your brain, though connected to it, or is it your brain
a. Are your thoughts, feelings, perceptions, sensations, and wishes things that happen in addition to all the physical processes in your brain,
b. Or are they themselves some of those physical processes
11. TASTE OF CHOCOLATE EXAMPLE IN SUPPORT OF DUALISM
12. Taste of chocolate example
a. All sorts of things happen after one bites piece of chocolate
b. Taste buds send electronic impulses to brain and further physical changes take place there
c. Finally you taste the taste of chocolate
d. Is that taste just a physical event in some brain cell
e. Or is it something of a different kind?
13. **Reason to think experience of taste is not something physical
a. Scientists who took off top of your skull and looked inside while you were eating chocolate would only see grey mass of neurons
b. Could measure electrical/chemical processes
c. Would not find/experience the taste of chocolate
14. Scientist would not observe your experience of chocolate even if she licked your brain
a. So it is not simply because the experience is a flavor experience that has to be tasted and not seen visually
b. Even if your brain tasted like chocolate, he would not have succeeded in getting into your mind and observing your experience of chocolate
c. He would have his taste of chocolate and you would have yours
15. Your experience of the taste of chocolate is locked inside your mind in a way that makes it unobservable by anyone else
a. Your experiences are inside your mind with a kind of inside-ness that is different from way your brain is inside your head
i. Someone else can open up your head and see what is inside, but they can’t cut open your mind and look into it
b. A person’s conscious experience is observable only from the inside by a person whose consciousness it is and it is not observable from the outside
16. Main argument:
a. Since mental events are not observable by everyone (and all physical things are observable by all)
b. Then our experiences and mental states can’t just be physical states of our brains
c. Then there is more to a person than her body
17. Dualism:
a. There is a soul (or some non-religious mental substance, mind) attached to your body in some way which allows them to interact
b. People made up of two very different things:
i. Physical organism
ii. Mental stuff (e.g., soul)
18. PHYSICALISM
19. Considerations against dualism (existence of soul/mental stuff)
a. Belief in a soul is old-fashioned and unscientific
b. Everything else in the world is made of physical matter (different combination of chemical elements)
c. Why shouldn’t people also be made of up of this?
d. Why can’t a complicated physical system like a human body/brain give rise to mental life?
20. How could philosophy show that people aren’t merely physical
a. Philosophy can’t tell us what stars or diamonds are made of so how can it tell us what people are made of?
21. Physicalism/materialism: People consist of nothing but physical matter
a. People’s mental states are physical states of their brains
b. Everything that exists is made of physical matter and that is all, people are no different
c. ???And hence science eventually will be able to explain everything, for science is what tells us about the physical world
22. Science will discover which states of the brain can be identified with which mental states (the experience of tasting chocolate, for example)
a. We will discover that experiences really are brain processes
b. Just as we have discovered that other familiar things have a real nature we couldn’t have guessed until revealed by science
i. E.g., Diamonds are composed of carbon, same material as coal
ii. Water is composed of hydrogen and oxygen, even though these two elements are nothing like water when taken by themselves
c. Might seem surprising that experience of tasting chocolate is nothing but complicated physical event in your brain
i. But no stranger than lots of other scientific discoveries
d. Only a matter of time before science discovers the biological nature of the mind
23. Dualist reply
a. These other discoveries where simply finding out what smaller physical things made up a physical substance
b. To analyze mental states in terms of physical states would involve analyzing an internal (and private) taste sensation by an externally observable physical substance
c. Science will never be able to show that a mental phenomenon is a physical one
24. DUAL ASPECT THEORY
25. Dual aspect theory (one thing, two properties view)
a. Dualism: you consist of a body plus soul and your mental life goes on in your soul
b. Physicalism: your mental life consists of physical processes in your brain
26. Dual aspect theory: Mental life goes on in the brain (not in your soul–so rejects dualism) but those experiences, feelings, thoughts, desires are not physical processes in your brain (rejects physicalism)
a. Our brains are not just physicals objects
b. They have lots of physical properties/processes, but also have mental processes as well
27. Brain is the seat of consciousness but its conscious states are not just physical states
28. Bite into chocolate produces a state in your brain with two aspects
a. Physical aspect involving electrical and chemical change
b. Mental aspect –the flavor experience of the chocolate
29. Scientist looking into your brain will be able to observe the physical aspect
30. You will undergo, from the inside, the mental aspect
31. Our brains have an inside that can’t be reached by outsider observer even if cut it open
32. You are not a body plus soul (dualism)
33. You are just a body, but your body (or brain) is not just a physical system
34. Object with both physical and mental aspects
35. There is something it is like from the inside to taste chocolate because there’s something it’s like from the inside to have your brain in the condition that is produced when you eat chocolate
36. PHYSICALISM (AGAIN)
37. Physicalism: Believes nothing exists but physical world studied by science, world of objective reality
a. They have to find room for feelings, desires, thoughts, and experiences (for us) in such a world
38. Functionalist defense of physicalism
a. Mental nature of mental states consists in their relation to things that cause them and things they cause
i. A mental state is anything that functions like a mental state (same inputs and outputs)
b. E.g., feeling of pain involves physical characteristic in our brain but what makes it pain is that it is the kind of state of your brain that is usually caused by injury and that usually causes you to yell and hop around and avoid the thing causing the injury
c. Pain is whatever is caused by injury and causes pain behavior
39. Nagel’s response
a. Not enough to make something pain that it causes you to yell and is usually caused by injury
b. Pains are pains also because they feel a certain way
i. And that is different from all their relations to causes and effects as well as the physical properties they have (if in fact they are events in your brain)
c. Nagel does not believe that inner aspect of pain (how it feels) and (of other conscious experiences) can be analyzed in terms of any system of causal relations to physical stimuli and behavior
40. NAGEL’S DUALISM
41. Two very different kinds of things going on in the world
a. Things belonging to physical reality which many people can observe from the outside
b. Other things belonging to mental reality which each of us experiences from the inside in his own case
i. Probably some other animals have insides like this too
42. Won’t have an adequate general conception of the world until we can explain how when physical elements put together in right way they form not just biological functioning organism but a conscious being
43. If consciousness could be identified with some kind of physical state, we could develop a unified physical theory of mind and body and perhaps unified physical theory of the universe
44. Nagel thinks that reasons against purely physical theory of consciousness so strong that likely a physical theory of the whole of reality is impossible
45. Physical science has progressed by leaving mind out of what it tries to explain, but there is more to the world than can be understood by physical science
46. ADDITIONAL CONSIDERATIONS ABOUT DUALISM VERSUS PHYSICALISM
47. Mental states do not have locations (or other physical characteristics) like physical states to so they must be different
a. It makes no sense to say of a mental states that they are at a certain location (“Where is my belief that nature has intrinsic value?” “How much does it weight and what shape is it and is it stationary or moving”)
48. If mental states are not physical it becomes a mystery how the two interact; how mental states can causally affect physical states (the brain) or how a physical state can causally affect a mental state (the mind)
a. Assumption: Only something physical can cause something else physical
b. But we know this causal interaction happens
c. Thus mental states must be physical states
Tom Nagel, The Mind-Body Problem
1. Explain what is at issue in the “mind-body problem.” Explain and compare how physicalism and the dualism understand mental states and people.
2. Explain Nagel’s main argument for accepting dualism. Why does he think the experience of the taste of chocolate is not something physical?
3. What is one consideration (reason) in support of physicalism
4. Explain the argument for dualism that claims that mental states do not have locations.
5. Explain why some think dualism has trouble explaining causation between mental and physical states.