h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I have a "thought experiment" which I believe may help. Your thoughts would be welcome.....

Imagine yourself standing facing a creature, alien, god or whatever, who can tell the future with precise accuracy.

Your hand is outstretched, and in it you hold an object, say an apple.

In the next ten seconds, you may either drop the apple, or keep hold of it.

Now, this creature knows the future, and therefore knows EXACTLY what you will do.

The point is, if the future is fixed, then you can't alter it whatever you choose. So, it doesn't matter if this creature tells you what it knows......

Whatever it tells you, what is to stop you doing the opposite?

Therefore, the future cannot be fixed, therefore free will to some degree must exist.

..........or does it? I thought this one up in the bath, so the proof may not be completely watertight.....(sorry!)

Maybe you'll find that you just don't feel like doing the opposite of what you're supposed to do. Also, pigs might fly. I mean, "doing forbidden things" or "doing the opposite of what you're supposed to" is human nature, right?

Here's another way to prove the existence of free will. Suppose that there's a consciousness that can perceive things, but can't affect reality. Let's call it "the ghost". It might watch me right now as I type these words. (It's probably thinking "Hey! How come this guy knows I exist?" Well, I know everything, that's why.)

Now suppose that the whole world is somehow "reset" to ten years ago. No one would notice anything; they would just go about their own business as usual, since they've forgotten everything that's happened the last ten years. Everyone except the ghost, who remembers everything that happened in those ten years that are now non-existent and "never happened".

The ghost watches as everyone relives those ten years. It is then suddenly given a human form and can interact with us mere mortals. It could then tell us if someone made a different choice the second time around, even though everything was exactly the same up until that very moment. I say "everything" and "exactly", and I mean it, the atoms and molecules and everything. If someone did make a different choice, we have free will. Otherwise, our choices merely depend on our experience (as an individual and as a race).

The question is this: Why would anyone make a different choice the second time around? Besides, free will does seem physically impossible. How do you make your brain reach a different decision when _everything_ is _exactly_ the same (eg all the neurons are firing just like they did the first time around)?

Hi magellan...

Here's the way I'd resolve the paradox: the creature knows what you will do - therefore it knows how its words will effect you. If it knows that you will do the opposite of what it predicts, then therefore it cannot predict the future truthfully: it must lie, or remain silent.

So, if the future is fixed, then an omniscient being CANNOT predict truthfully to those who wish to do the opposite of whatever is predicted - a corrolary of this is that you can't have an omniscient, omnipotent, being.

Who cares if the future is fixed, though - as long as it's fixed BY US?

iaoth:

I still don't understand how you can equate randomness with free will. If I am certain to drop an apple I am no less 'free' than if I have a 50% chance of dropping it, and a 50% chance of keeping hold of it.

Free will is a high-level concept - it seems nonsensical that its existance or otherwise is determined solely by whether the physicists "Theory of Everything" turns out to be deterministic or not. That'd be like finding out that who my father is is determined solely by the size of the gravitational constant...

Gravitational constant, you say... Hmm, yes... Yes, that does sound plausible.

Free will isn't necessarily randomness. But what else but randomness could it be? In my example, why else would a person make a different decision the second time around? Depending on my mood, I either see the universe as one big system, ie when this happens, that happens, and so on, or I think there's "more to it than that". Right now, I believe that the notion of "more" is just silly. But that would mean no free will, since our brains would strictly follow preset laws, ie when these neurons fire, those neurons fire, and so on. So maybe there is "more". But what might that be, if not randomness?

Sure, you might argue, as Hofstadter, that the high-level concepts really "pushes around" the low-level things such as molecules and neurons. (I'm referring to "Who pushes whom around in the careenium?") However, if free will is dependant on some sort of holism, the question boils down to this: What is the Ultimate Truth, holism or reductionism?

Well, it depends what you mean by free will - end of the day, it's just words. If free will is just randomness at the most fundamental level of existance - well, then it's not a terribly relevant property, and I don't see that possessing it, or not, makes any difference to anything.

Again with an analogy: suppose you told me that I had property "wibble" if I contain more carbon atoms than oxygen atoms in my body. Now, science might tell me that I either have wibble, or I don't have wibble - but before I care whether I have wibble or not, I would be wanting to know why I should care...

I think what's important isn't whether we actually have randomness or not - what's important is that our brains fool us into believing we make things called 'choices' - and it is this self-delusion that gives us 'free will'.

Our brains fool us into thinking all kinds of things - for example, we believe that we have a unified thought, when it is experimentally clear that the two hemispheres of our brain work largely independantly. But that doesn't mean that "I" don't exist - in fact, without the self-delusion (actually, "selfs-delusion": both hemispheres get fooled), "I" wouldn't exist - it is the way we lie to ourselves that makes it so.

At a higher level - there's no such thing as "Germany" - it's a purely arbitrary line on the ground that our society fools itself into thinking is important. But because society fools itself into thinking so, it IS important - and wars have been fought over where the line is drawn.

So there you go: free will is a delusion, but a potentially useful one (or it would not have evolved). The truth is an irrelevance that can be usefully swept under the carpet and/or left to the theoretical physicists...

Yep. That post summed it up rather well, I think.

Quite right, gentlemen. I shall now demonstrate my free will by going down the pub.

MyRedDice:
"a corrolary of this is that you can't have an omniscient, omnipotent, being."

I think this should be:
"a corrolary of this is that you can't have an omniscient, omnipotent, being that tells you what's going to happen."

As long as it doesn't tell you that it knows what youre going to do, theres no problem with you always trying to do the opposite of what is predicted. It can still predict what you're going to do.

OTOH, the mere fact that it knows what youre going to do must alter some part of its brain from what it would be like if it thought you would do something else, so theoretically that knowledge could still affect you, and it couldn't know for sure that its knowledge itself might alter the future. I can think of 3 ways out of this:

1) Somehow its prediction knowledge is consistent with the prediction itself, so it doesnt matter if the fact of its knowledge 'leaks out' of its brain (but how could such a self consistent loop arise?)

2) It is outside of the universe and cannot affect you at all.

3) It is on Alpha Centauri and only predicts your future 4 years ahead (so light speed 'insulates' your actions from its knowledge of the future).

The fact that it CAN'T tell you what is going to happen means that it isn't omnipotent - it is not all-powerful: it can't even tell the truth.

1) works fine: for examples of such self-consistent loops, just read a bunch of sci-fi. It's the equivalent of the time travel problem - just as you can have a closed loop in time which is self-consistent, so you can have a closed loop in causality which works the same way.

Practically, you'd need to be able to deal with the infinite regress somehow - you're essentially finding a fixed point: if A1 is the initial prediction, and A2 is the prediction after taking into account having made A1, and A3 for A2... then you want A-infinity. This limit won't always exist, but where it does, perfect prediction is possible.

My brain hurts....

The original idea was simply that,if the future is fixed, then it doesn't matter whether you know it or not because you couldn't change it anyway.

Of course, this only holds true for your individual frame of reference. If you accept the "many worlds" theory of quantum physics, then every time you perform the experiment, the universe splits in two anyway and both outcomes happen......

(You could also say the experiment simply demonstrates how awkward and contrary human beings are!)

Lucinda - omnipotence - yeah I see what you mean. Though I've often heard omnipotence defined as being able to do anything that isn't logically impossible, and this is skirting near to logically impossible. Dunno, maybe it gets out of it by telling the truth then forcing (using omnipotence) you to do what it said you would.

1) self-consistent loops - yes they're logically possible, but you sortof need omnipotence to set them up. If all you've got control over is what the prediction is, then yeah your best hope is an infinite regress that you hope converges

And all the time while you're predicting away, time continues and new information comes in that you have to deal with. Plus is it really possible to predict (or simulate) something with perfect accuracy using less matter/energy/time than the thing you're trying to simulate? Seems unlikely to me. I.e. our simulator/predictor would have to be outside our universe anyway. (Or maybe using quantum computers? Or do you need to be simulating them also anyway?)

determinsim holds that every event is the necessary result of a chain of causes leading up to it, a chain that runs indefinately into the past. one implication of this is that everything in the universe is, in principle, completely predictable. this makes free will impossible, so which do we go for?
we could accept determinsim and reject free will:

1. every action is either caused or incaused (i.e. a random occurence)
2. if an action is caused, then it was not chosen freely and the person cannot be held morally responsible.
3. if an action is uncaused (random occurence) then the performer of the action is not morally responsbible
thus we are not morally responsible for what we do

Is the creature subject to our physical laws (his decision is predetermined)?

If so then the creatures dicision is predetermined and so your decision will be made on this basis (external input - surrounding environment down to the beat of a butterflys wings [complex non linear systems etc], your current mindset - if you are 25 years old the you have an extremly complex mindset based on 25 years of reactions to complex systems; and the decisions based on the above and what the creature says)

back to predetermined i'm afraid - (does it really matter? - i believe it is predetermined, but hey! it doesn't stop me from acting/thinking as though it isn't during my life.)

----

You could have the cartesian point of view - the only reality that is certain (to you) is your personal experience - this leads to the posibility that nothing else is real, its all an illusion, someone/thing could be rigging the whole game! - game over.

I don't know if anyone's already said this, but anyway. Everything that happens has a cause and an effect. For the most part, the cause comes first, but in this alien guy's case, the effect (What he tells you) is based on what will happen (whether you drop the object or not.) But here, the outcome of the effect depends on the outcome of the cause, which in turn decides the outcome of the effect. So the only two possibilities to end the are for it to be impossible for the alien to tell you what you're going to do (But still know what you will do), or the loop will simply 'iron itself out'. In other words, for example, the alien tells you you will hold onto the object. You drop the object, but then immediately forget he told you to hold onto it and think he said to drop it. The alien will never have told you to hold onto it, and put simply, you'd be changing history.

Actually there are 2 frames of reference (F.O.R).

in this case you've obviously taken a human F.O.R

The truth of the matter is:
Think of it like 2 clocks. In our universe there is one clock, and outside the universe there is another. If you change the future or past or both, then this clock goes backwards or forewards respectively. However the clock outside the universe is still going foreward.

My point is, the universe is a chain of events, part of a larger chain of events. There are a number of possible futures but only one of them is the right one. Which one is it?

If you had knowledge of the future and did nothing with this knowledge then that's still part of the chain of events the future will ocurr or not depending on other events in your present, or past.

If you did something with the knowledge and you think you've changed the future you are wrong because you've only stopped one possible future from happening and have still carried on into the future.

My point is whatever is going to happen will happen.

In predicting the future you have got to factor in what outcome there will be if you have knowledge of a possible future.
Changing the future means that you have failed to factor in your response to one series of events, and therfore your prediction will be wrong in the first place.

The past is fixed, the way objects change are governed by a series of laws/equations, So the future is also fixed. If you ignore one equation or don't know of it then your answer/prediction is going to be wrong.

Always remember, your thought process is part of the chain of events and can be predicted based on a number of physical factors e.g your personality, your experiences in life, your genes, your situation etc.
Nothing is random, it just appears to be that way.

The creature might know the future simply in the way that human beings know the past by using their memories. It might have some way of seeing what was going to happen. But the fact that we can remember the past and that it is, in that sense fixed, doesn't mean that we had no choice at the time of the event. Why should knowing what will happen mean that we have no free will over what we do now or in the future?