Thursday, February 28, 2008

Free Will in the Multiverse

Consider undergoing brain surgery. During the operation you are awoken so that the brain surgeon can do tests on you to see if certain brain areas can be cut away safely. During these tests you may be able to see parts of your own brain. What a strange sight that must be! But however closely you look at your own brain, you can never see it in full detail. The reason is that everything you see must be stored in your own brain, so storing the entire state of the brain will necessarily exhaust all the available brain capacity. Note that this argument you can take "full detail" to be only the relevant information about the brain that defines you.

This means that we cannot know, even in principle, who we really are. In a multiverse setting, this in turn implies that we must always associate ourselves with ensembles of near exact copies. Assuming that each of our copies evolves deterministically, their evolution will diverge after a while. So, our future is not deterministic. And this will, of course, happen whenever we feel that we have a choice over our actions and we haven't made up our minds on what action to take.

Because the argument above shows that our consciousness should be associated with some ensemble of near exact copies and not with any particular copy, it seems that from the perspective of the conscious entity, there does exist a real free will and not just an illusion of it as is the case in single universe settings.

6 Comments:

Blogger Chuck said...

You are assuming that knowledge of who we really are requires all details and information stored in the brain. However, people with various traumatic brain injuries retain their self-identity, even if their personalities undergo what appears to their acquaintances to be a significant change.

Thu Feb 28, 05:18:00 PM PST  
Blogger Neil' said...

I don't think complete self-knowledge is essential or closely related to free will (choice), nor is relationship to copies or near copies of yourself. Choice is not being determined by your parts, of being a whole that is greater than the sum of those parts. It is a knife edge of you could do one thing, or the other, and there's something bigger than the little stimuli that breaks the tie. We don't really understand what that is.

Most reductionists (e.g. Dan Dennett) don't believe in a unified self now anyway, but it is hard to explain how a mess of little sub programs etc. can focus attention and give us the flexibility to suddenly change from one course of action to another.

Thu Feb 28, 06:03:00 PM PST  
Blogger Justin said...

rubbish. that's only a limited view of looking at it. there are many other underlying factors that could prove either there is or isn't free will.

Fri Apr 11, 08:39:00 AM PDT  
Anonymous wolfgang said...

Count,

your idea is very similar to how I am thinking about this.
But my argument is more general: Any physicist who tries to measure the exact state of your brain would necessarily disturb it.
And this disturbance can not be controlled due to the argument you make (a physicist cannot know her own state exactly).

Sun May 04, 10:04:00 AM PDT  
Anonymous wolfgang said...

Argh, the link above should be this.

Sun May 04, 10:05:00 AM PDT  
Anonymous Dani said...

I disagree with the assumption that you must know your entire brain state to make a prediction, but anyway, suppose a huge computer scans your entire brain, makes a computation and predicts what you're going to do. It prints that on paper. After 1 day you look at the papers and see that the computer predicted everything that you did. Where your free will now?

Fri Feb 22, 12:26:00 PM PST  

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