Zombies Philosophy of Mind BRENT SILBY Unlimited (UPT)

What is a Zombie? Brainstorm definition…

What is a Zombie? A philosophers zombie is identical to a person Only difference is it has no conscious experiences. Can we imagine what that is like to be a Zombie?

What is a Zombie? What is a conscious experience? Experience of blueness when looking at blue. The experience of pain. Its the essence of any experience. It is the thing that is hard to define and track down. e.g. The experience of pain--where is the pain? Not in the pin, Not in the finger, cant find the feeling in the brain (just neural activity there). e.g. The experience of blue--where is the blue color? Its not In the world (just EM Radiation), not in eyes or brain (just Nerve, electrical activity there) Remember Mary the colorblind scientist

If brains are like computers, pain might work like this BUT WHERE IS THE FEELING ???

What is it like to be a Zombie? Try to remember a time when youve walked home and not remembered the walk. You get home and when you think back, you cant actually remember much of the journey. Its a blank. This happens from time to time. You get home and cant remember the trip. But you know that during the trip you were thinking about crossing the street, moving passed people, etc. You were making decisions about which way to go. You were no doubt having experiences, but they were not Conscious experiences because when you try to remember its all blank. That non-conscious time is what it is like for a zombie.

Logical possibility of Zombies? The difference between physical possibility and logical possibility If something is physically possible, then it can happen in this world (or universe). For example, it is physically possible for cars to travel 700 kph. It is physically possible for a star system to contain 20 planets. It is physically impossible to escape from a black hole. It is physically impossible for anything to travel faster than light.

Logical possibility of Zombies? Something is logically possible if you can imagine a possible world in which it is true. For example: it is logically possible to escape a black hole. Its not physically possible because it cant happen in our universe. But it is logically possible because another possible universe may have different laws of physics. Lots of things are logically possible. In fact almost everything is logically possible. If you can imagine something without contradiction, then it is logically possible.

Logical possibility of Zombies? Something is logically impossible if it yields contradiction Examples of logical impossibilities: * a square circle * 1+1=3 * For an object to not be identical to itself

Logical possibility of Zombies? Imagine that you have a Zombie Twin * Your zombie twin looks identical to you. * Your zombie twins brain is exactly the same as yours. * Your zombie twin has the same psychology as you. * It has the same thoughts as you. * The only difference is that it doesnt have Conscious experiences. Its forever like the time you walked home and cant remember the experience. Since you can have those non-conscious experiences, it shows that non-conscious experiences are possible. It follows that zombies are logically possible.

So What? Heres the argument 1 Zombie brains are identical to human brains 2 Zombie brains work exactly the same as human brains 3 Zombies do not have conscious experiences Therefore Conscious experiences are not dependent on brains Therefore Conscious experiences cannot be explained by brain science Does it follow that conscious experience can exist without brains? Can a person be conscious without a brain? Perhaps as a soul? DISCUSS… Why/Why not?

PROBLEMS The example about walking home and not having conscious experiences does not work. Try to think of another explanation for this experience… Heres a possible explanation… e.g. it could be that you simply dont remember walking home. Perhaps you had conscious experiences, but they were not encoded in memory.

But… Some people may be partial zombies… BLINDSIGHT: (diagram on board) * But.. When asked to GUESS where the spot was flashed, the patients get it right…[NEXT SLIDE…] * People who suffer from a particular neurological condition have a blindspot in their visual field. * They are entirely unaware of anything that is in their blindspot. * They have no conscious experience of items in their blind spot. * Scientists do experiments. They flash a pinpoint of light into a random spot in the patients visual field. The patient says they dont know where the spot was flashed.

So what? Well, this is an example of someone who is perceiving but is not conscious of the perception. Is this person a partial zombie? Does this mean that complete zombies are possible? (they act like us, but are non-conscious) Perhaps the person sitting next to you is a zombie ! How would you know? Discuss…

Does all this show us that consciousness is something extra to the brain? Perhaps some non-physical part of the brain? Or does science simply not yet know how a brain produces conscious experiences?

Powerpoint by BRENT SILBY Produced at UPT Christchurch, New Zealand