1. The Problem of Consciousness

2. The Problem of Consciousness
However, our last puzzle about the mind is thought to be a problem for both type physicalist theories and for functionalist theories as well.

3. The Problem of Consciousness
There is a very strange quality of our mental lives that makes it very difficult to see how any version of physicalism could be true.

4. The Problem of Consciousness
There is a special character, a “what it’s like” to be in certain kinds of mental states:
Seeing red
Being in pain
Getting tickled
Having an orgasm
Nagel calls this the subjective character of experience.

5. The Problem of Consciousness
This is one of the most central and important features of our mental life. But it is also deeply mysterious.

6. Announcements
A review sheet for the final exam will be handed out on Friday. There will be a review session on Wednesday June 11 at 5-7 PM, in GIRV 1004.

7. What It’s Like to Be a Bat
Bats experience the world in a fundamentally different way than we do. Bats can see, but rely primarily on their hearing to navigate and hunt.

8. What It’s Like to Be a Bat
They do this by echolocation: emitting a sound and using the bouncing sound waves to understand things about their environment.

9. What It’s Like to Be a Bat
Using this method they can find out things about objects in their environment that we can only usually do by sight:
Distance
Size
Shape
Motion
Even texture

10. What It’s Like to Be a Bat
We know alot about bat echolocation:
We know the principle behind it.
We know nearly everything about bat brains.
We know about their auditory systems and why they are so sensitive.

11. What It’s Like to Be a Bat
We can keep studying bats until we know every physical thing about their brains and their sensory systems. But, according to Nagel, we still wouldn’t know what it is like to be a bat.

12. What It’s Like to Be a Bat
“Even without the benefit of philosophical reflection, anyone who has spent some time in an enclosed space with an excited bat knows what it is to encounter a fundamentally alien form of life…Bat sonar, though clearly a form of perception, is not similar in its operation to any sense that we possess, and there is no reason to suppose that it is subjectively like anything we can experience or imagine.” (229)

13. What It’s Like to Be a Bat
No matter how much we study the physical nature of bats, we will never get at what it is like to be one. The only way to do so is to experience things the way a bat does first-hand.

14. What It’s Like to Be a Bat
So it seems as if, no matter how advanced they get, purely physicalist explanations will always leave out something vital about minds. No physicalist explanation will provide us an understanding the subjective character of experience.
New article on what it is like to be an octopus that I have put up on the website.

15. What It’s Like to Be a Bat
Of course, we know what it is like to be a human and can study the corresponding neuroscience.
But we know what it is like to be us, not because of scientific physicalist explanations, but by experiencing it.
(e.g. explaining red to a blind person)

16. Mary and The Knowledge Argument
Frank Jackson presents another sort of case designed to establish the same conclusion.

17. Mary and The Knowledge Argument
Mary is captured as a baby and placed in an all black and white room with lighting that makes her skin and such appear similarly without color.
She becomes the most brilliant scientist in history and learns everything there is to know about color, color-vision, and how the neural system works.

18. Mary and The Knowledge Argument
In short, she knows all the physical facts having to do with seeing red.
One day Mary is released from her prison and just outside the door she finds an apple (red delicious).
Does Mary learn anything new?

19. Mary and The Knowledge Argument
Most people say yes! She has learned what it is like to see red.

20. Mary and The Knowledge Argument
If this is so, we have a powerful argument against physicalism of any kind:
Mary Argument
Before leaving her room, Mary knew all the physical facts having to do with seeing the color red.
When Mary sees the apple she learns something new: namely what it is like to see red.
Therefore, what it is like to see red is not a physical fact, or something that can be learned by studying merely physical facts.

21. Mary and The Knowledge Argument
In other words, the conscious experience of seeing red is something that the physical sciences could never explain, even in principle.

22. The Subjective Character of Experience
As a matter of fact no one has a very good idea of what this “what its like”-ness is, or how it relates to physical things.

23. The Subjective Character of Experience
Despite all of our knowledge, there still seems to be something inherently “spooky” about minds.

24. The Subjective Character of Experience
Nagel and others don’t rule out that some physicalist explanation will eventually be offered, but it is almost impossible to imagine what one would look like given what we currently know.

25. The Subjective Character of Experience
“It would be a mistake to conclude that physicalism must be false…It would be truer to say that physicalism is a position we cannot understand because we do not at present have any conception of how it might be true…At the present time the status of physicalism is similar to that which the hypothesis that matter is energy would have had if uttered by a pre-Socratic philosopher. We do not have the beginnings of a conception of how it might be true.” ( )

26. The Subjective Character of Experience
How to deal with the subjective character of experience is one of the most puzzling questions in philosophy of mind and the cognitive sciences.