ZombiesPhilosophy of Mind

BRENT SILBYUnlimited (UPT)

What is a Zombie?

• Brainstorm definition…

What is a Zombie?

• A philosopher’s 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 ofpain. It’s the essence of any experience. It is the thing thatis hard to define and track down.

e.g. The experience of pain--where is the pain? Not in the pin,Not in the finger, can’t find the feeling in the brain (just neuralactivity there).

e.g. The experience of blue--where is the blue color? Its notIn the world (just EM Radiation), not in eyes or brain (justNerve, 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 you’ve walked home and notremembered the walk. You get home and when you thinkback, you can’t actually remember much of the journey. Itsa blank.

• This happens from time to time. You get home and can’t 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 totravel 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 possibleworld in which it is true.

For example: it is logically possible to escape a black hole. It’snot physically possible because it can’t 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 islogically possible. If you can imagine something withoutcontradiction, 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 twin’s 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 doesn’t have Conscious experiences. Its forever like the time you walked home and can’t 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?Here’s 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 brainsTherefore 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 consciousexperiences does not work.

Try to think of another explanation for this experience…

Here’s a possible explanation…e.g. it could be that you simply don’t remember walking home.

Perhaps you had conscious experiences, but they werenot 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 patient’s visual field. The patient says they don’t know where the spot was flashed.

So what?

Well, this is an example of someone who is perceiving but is notconscious 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 extrato the brain? Perhaps some non-physical part of the brain?

Or does science simply not yet know how a brain producesconscious experiences?

Powerpoint by BRENT SILBY

Produced at UPTChristchurch, New Zealand

www.unlimited.school.nz