Announcements A draft of the review sheet is online. Check back on Friday for the complete version. The final exam is Wednesday June 10 th from 4-7 PM. Bring a blue book! Papers handed back on Friday.

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

The Problem of Consciousness There is a special character, a “what it’s like” to be in certain kinds of mental states: 1. Seeing red 2. Being in pain 3. Getting tickled Nagel calls this the subjective character of experience.

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

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.

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.

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: 1. Distance 2. Size 3. Shape 4. Motion 5. Even texture

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)

What It’s Like to Be a Bat We know alot about bat echolocation: 1. We know the principle behind it. 2. We know nearly everything about bat brains. 3. We know about their auditory systems and why they are so sensitive.

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

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.

What It’s Like to Be a Bat “Suppose that we could somehow peek inside a bat’s mind and find out what it is like to be a bat…Would that help us derive or otherwise acquire, or to build an objective physical account of bat consciousness? The answer must be a clear no.” (Kim)

What It’s Like to Be a Bat Kim thinks that the problem goes in both directions. 1. You can’t derive all the facts about consciousness from physical facts 2. You (clearly) can’t derive the physical facts just from feeling what its like to be a bat!

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)

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

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.

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?

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

Mary and The Knowledge Argument If this is so, we have a powerful argument against physicalism of any kind: Mary Argument (1) Before leaving her room, Mary knew all the physical facts having to do with seeing the color red. (2) When Mary sees the apple she learns something new: namely what it is like to see red. (3) Therefore, what it is like to see red is not a physical fact, or something that can be learned by studying merely physical facts.

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.

Announcements The final exam is Wednesday June 10 th from 4-7 PM in this room. Augi will hand back your papers after you complete your course evals.

Recap from Last Time Two Cases (1) Nagel’s Bat (2) Mary the Neuroscientist Both cases seemed to show that even you have all the physical, functional and computational information about certain mental states you still need not know what it is like to be in them.

The Hard Problem of Consciousness This is what David Chalmers calls The Hard Problem of Consciousness. The Easy Problem is to explain how a physical system could believe, remember, perceive, think, and so on. Most people think functionalist and computational/functional stories do a pretty good job here. (Enough to move forward on anyways) The Hard Problem of Consciousness is to explain how qualia depend on physical states and processes.

The Explanatory Gap At the heart of the problem are some seemingly simple questions: 1. Why does a particular neural firing feel this way? 2. Couldn’t it feel another way? 3. Why does pain feel the way it does? 4. Couldn’t a state play the same functional role as pain but feel different? Without answers to questions like these, physicalist accounts like CTM and functionalism seem incomplete.

Inverted Spectrum (Again) Invert Nonvert

The Explanatory Gap Why couldn’t pain feel different to someone else but still play the same functional role? Suppose what they call “pain” feels to them like a strong itch feels to you. They hate it and avoid it as much as you do, and it bears the same relation to all their other states.

The Explanatory Gap Is this case impossible?  Why?  What reason besides simply endorsing functionalism would we have to rule it out?

The Explanatory Gap This deficiency of physicalist explanations to explain qualia is sometimes called The Explanatory Gap.  Physicalist theories have the resources to explain almost everything in the natural world including most of the features of the mind (of course we still have a lot to learn even here)  But no one has a very convincing story to tell about how qualia fit into this picture.  Some people (Dan Dennett) are willing to bite the bullet and deny that qualia exist  Others try to deny the possibility of cases like the Inverted Spectrum  None of this is terribly satisfying

The Explanatory Gap The problem is so hard that it has led some philosophers (David Chalmers) back to something like dualism!  This is usually not substance dualism  In Chalmers’ view (for instance) basic particles of matter have some non-physical properties.  In other words, atoms, electrons, everything has mental (or proto-mental) properties  It is only when you gather them all together in a certain way that you get minds like ours

The Explanatory Gap It is possible that some satisfactory physicalist explanation will eventually be offered. But it is almost impossible to imagine what one would look like given what we currently know.

The Explanatory Gap “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.” ( )