Is determinism impossible?

[partinobodycular]

A la the "Halting Problem", is it impossible for the state of any system containing conscious beings to be sufficiently knowable such that it's future is entirely predictable? Or does the ability of those conscious beings to act upon that knowledge mean that the future is fated to always be unknown, because knowing it, means that one has the option to change it, whereupon the cycle becomes unending.

Knowledge of what happens in the future changes what one does in the present, which then changes what happens in the future, and so on, and so on.

Cassandra was fated to know the future but never be able to change it. But if you could change it, then doesn't it become unknowable?

Hence the problem of determinism. It makes reality predictable... which, thanks to that knowledge, makes it unpredictable.

 

[essentialsaltes]

But if you could change it, then doesn't it become unknowable?

You're begging the question by assuming that 'free will' kills determinism.

A child dashes in front of your moving car, and you know you will hit it. So you apply the brake.

Did you choose to apply the brake and alter the future? Or was your choice determined by your nature and this new stimulus?

The future may be unpredictable (to us), but this does not imply it is undetermined.

 

[partinobodycular]

A child dashes in front of your moving car, and you know you will hit it. So you apply the brake.

This analogy isn't quite correct, because you know that you'll hit the child, only if you don't apply the brakes. So from your perspective the future has two equally viable options. But if determinism is true then you could've known a week ahead of time that you were going to hit the child. The implication being that if determinism is true then you can do absolutely nothing about it. On the other hand, if you can do something about it, then you can't know the future, and determinism can't be true.

So which is it? Could you know a week ahead of time that you were going to hit the child, and you can do nothing about it? Or you could do something about it, in which case you couldn't know what's going to happen a week ahead of time?

The ability to predict the future implies the ability to change the future, which implies the inability to predict the future.

 

[essentialsaltes]

But if determinism is true then you could've known a week ahead of time that you were going to hit the child.

Determinism doesn't imply that everyone has perfect knowledge of the future.

You might have a general knowledge that you usually drive to the store that day, but you have no knowledge of the plans of every human being on the planet, much less everything else that exists in the world.

you can't know the future, and determinism can't be true.

The fact that human knowledge is finite doesn't imply determinism can't be true.

 

[Occams Barber]

A la the "Halting Problem", is it impossible for the state of any system containing conscious beings to be sufficiently knowable such that it's future is entirely predictable? Or does the ability of those conscious beings to act upon that knowledge mean that the future is fated to always be unknown, because knowing it, means that one has the option to change it, whereupon the cycle becomes unending.

Knowledge of what happens in the future changes what one does in the present, which then changes what happens in the future, and so on, and so on.

Cassandra was fated to know the future but never be able to change it. But if you could change it, then doesn't it become unknowable?

Hence the problem of determinism. It makes reality predictable... which, thanks to that knowledge, makes it unpredictable.

Determinism does not make things predictable in the real world. While determinism implies theoretical predictability the reality is we can never know enough to guarantee complete predictability.

There are also degrees of predictability. How detailed must a prediction be to be regarded as an accurate prediction? If I release a tennis ball, I can predict it will fall vertically towards the ground. I cannot predict details of the ball's spin as it falls, nor can I predict the position and state of every atom in the ball and its environment.

OB

 

[partinobodycular]

Determinism doesn't imply that everyone has perfect knowledge of the future.

Determinism does not make things predictable in the real world. While determinism implies theoretical predictability the reality is we can never know enough to guarantee complete predictability.

This is a theoretical problem, and in theory complete knowledge is indeed possible. At least as far as proponents of determinism are concerned. Therefore, theoretically, the future should be predictable, and if it's predictable, then it's changeable, and if it's changeable, then it's not predictable.

As for the real world, how does one overcome the ever increasing n-body problem? For example, is it really possible to predict the outcome of a given set of stimuli on a system as complex as the human brain? And if you can't predict the behavior of the human brain with absolute perfection, then determinism ceases to apply.

 

[Neogaia777]

A la the "Halting Problem", is it impossible for the state of any system containing conscious beings to be sufficiently knowable such that it's future is entirely predictable? Or does the ability of those conscious beings to act upon that knowledge mean that the future is fated to always be unknown, because knowing it, means that one has the option to change it, whereupon the cycle becomes unending.

Knowledge of what happens in the future changes what one does in the present, which then changes what happens in the future, and so on, and so on.

Cassandra was fated to know the future but never be able to change it. But if you could change it, then doesn't it become unknowable?

Hence the problem of determinism. It makes reality predictable... which, thanks to that knowledge, makes it unpredictable.

If you came to 100% absolute full knowledge of how everything is caused, or is predetermined, then you would then have to also ask yourself if that was also not fated or predetermined, and if the choices you would make based on that knowledge, and when you would get it, was also not fated, or predetermined, etc.

There is no escape from determinism even if you had the full knowledge, because that also might have been fated, or predetermined, etc. You'd have to seek something outside of or beyond this reality in order to escape it, etc.

The only way to make a 100% non-determined or predetermined choice/action, is for it to be 100% totally and truly completely 100% random, which means absolutely no outside influences, or prior causes, etc, otherwise, there is no escape from it, etc.

Now, or now that that has been said, I'm absolutely dumbfounded at all the people who think this means they should not try to do or choose anything at all, etc. Absolutely dumbfounded by that, etc. Because even if there is another, or maybe several other entities with this knowledge, then how do you know it is not also your fate to do/choose/act, just as much as it may be for you to not do/choose/act in any given moment, etc. Thing is, we don't know this yet, and as deep and complex and complicated/deep that this knowledge is, we probably or maybe never will, etc. But even if we could, then you have to go right back to what I originally just said at the start of this post/reply again, and ask yourself if that was not also fated, or predetermined, etc.

None of this should change what we would normally just originally choose or do, etc. Because until we have all-knowledge, it is inconsequential, etc. And that's exactly as it should be, etc. Everything is still 50/50 in our eyes, etc. So just do what you feel is good, or what you think is good, or what comes to you that you think might be good, "whenever", or don't, etc, like I said, it's whatever is put before you, or whatever comes to you, and "the rest", "doesn't really matter", etc.

Use your brain, or be wise, but don't second guess everything to death, etc. Really "whatever is put before you", and "however you'd normally choose to do it" is really quite simple really, etc.

For us it is still unwritten, even if it has already been written, because we don't know how things are supposed to go/be either way, etc.

I recommend you just always do/choose always whatever you think is good, or is best, etc, but of course, you don't have to do/choose that way all of the time either, etc, because none of us knows our fate, or the way things are supposed to go, or should be, etc.

God Bless.

 

[essentialsaltes]

For example, is it really possible to predict the outcome of a given set of stimuli on a system as complex as the human brain?

"This is a theoretical problem, and in theory" you could. And you might discover that running over a child next Thursday was as ineluctable as the sunrise.

And if you can't predict the behavior of the human brain with absolute perfection, then determinism ceases to apply.

You can't and I can't. But that's just due to our limitations. That doesn't mean it's theoretically unpredictable. Especially when your thought experiment is presupposing determinism.

 

[Occams Barber]

This is a theoretical problem, and in theory complete knowledge is indeed possible. At least as far as proponents of determinism are concerned. Therefore, theoretically, the future should be predictable, and if it's predictable, then it's changeable, and if it's changeable, then it's not predictable.

I am a 'proponent of determinism' and I know that despite what may be theoretically possible complete predictability is actually impossible. Your theoretical problem does not exist.

As for the real world, how does one overcome the ever increasing n-body problem? For example, is it really possible to predict the outcome of a given set of stimuli on a system as complex as the human brain? And if you can't predict the behavior of the human brain with absolute perfection, then determinism ceases to apply.

Why not? There's nothing special, in a deterministic sense, about the human brain. Predictability and determinism are two different concepts. An event does not cease to be determined because I'm unable to predict it.


Determinism exists because particles and forces in the Universe act and react according to the rules (known and unknown) governing physics and chemistry. As a part of the universe the particles and forces you are made of also act according to these rules. You have no control over this since you cannot manipulate the rules of physics. It may seem as if you are in control but if you drill down to the level of basic particles it becomes obvious that your behaviour is the sum total of the action and interaction of these basic forces and particles.

OB

 

[Bradskii]

A la the "Halting Problem", is it impossible for the state of any system containing conscious beings to be sufficiently knowable such that it's future is entirely predictable?

No. Because you'd need to know all the details of every particle that is in existence. And know how each particle interacts with all other particles. If you had ten particles then the number of combinations are 10 billion (from here: Combinations and Permutations Calculator). One hundred particles and you start running out of zeroes. A universe full of particles and it's theoretically possible to check all combinations if it was static. But as it changes (every Plank unit of time?) then it's not even theoretically possible. The amount of changes occur faster than physics will allow you to calculate.

But back to more mundane scenarios...it's practically impossible. But still determinate. And as has been mentioned a couple of times, determinism and predictability are two different concepts. When an event occurs you can work back to determine some of the proximate causes. The empire fell because the war was lost. The war was lost because the battle was lost. The battle lost because the fight was lost. The fight was lost because the horse threw a shoe. But you can't predict the fall of an empire because of a loose nail.

 

[Neogaia777]

No. Because you'd need to know all the details of every particle that is in existence. And know how each particle interacts with all other particles. If you had ten particles then the number of combinations are 10 billion (from here: Combinations and Permutations Calculator). One hundred particles and you start running out of zeroes. A universe full of particles and it's theoretically possible to check all combinations if it was static. But as it changes (every Plank unit of time?) then it's not even theoretically possible. The amount of changes occur faster than physics will allow you to calculate.

But back to more mundane scenarios...it's practically impossible. But still determinate. And as has been mentioned a couple of times, determinism and predictability are two different concepts. When an event occurs you can work back to determine some of the proximate causes. The empire fell because the war was lost. The war was lost because the battle was lost. The battle lost because the fight was lost. The fight was lost because the horse threw a shoe. But you can't predict the fall of an empire because of a loose nail.

I'm guessing that you guys mean "unable to be fully predicted/known by us", I'm guessing, etc.

But my guess is is that there most definitely are stories in there of how a "loose nail led to the fall of an empire", or other things like that, etc. I bet they are most definitely in there, etc, and maybe are in there "in spades" maybe, etc. Like the butterfly effect, or chaos theory, only most definitely "not chaos theory", or something like that, etc. Anyway, I bet you a bunch of those are most definitely in there. Maybe it comes down to someone's sense of humor maybe, or something like that, etc. And maybe one day, we'll know them, and will all be let in on all the "jokes", but just not yet, etc.

Anyway,

God Bless.

 

[partinobodycular]

Because you'd need to know all the details of every particle that is in existence. And know how each particle interacts with all other particles. If you had ten particles then the number of combinations are 10 billion (from here: Combinations and Permutations Calculator). One hundred particles and you start running out of zeroes.

So you're resorting to an argument from incredulity?

You do realize that the number of particles is totally irrelevant? Because not only don't you know where all of them are... you don't know where any of them are. And it's not just that you don't know where they are, it's that nature itself doesn't know where they are. So how can reality possibly be deterministic, much less predictable, if it's impossible to know where anything is?

Generally we do this by assuming that all of those 'unknowables' average out, and that on larger scales the exact position of all of those particles doesn't matter.

But here's the weird bit, it's not really about how complicated the system is, even three measly bodies are sufficient to make a system unpredictable. It's still deterministic, it's just not predictable... supposedly, not even by God Himself. So here's a question, in a system wherein the initial conditions are insufficient to predict an outcome... aren't deterministic and unknowable the exact same thing?

 

[Neogaia777]

So you're resorting to an argument from incredulity?

You do realize that the number of particles is totally irrelevant? Because not only don't you know where all of them are... you don't know where any of them are. And it's not just that you don't know where they are, it's that nature itself doesn't know where they are. So how can reality possibly be deterministic, much less predictable, if it's impossible to know where anything is?

Generally we do this by assuming that all of those 'unknowables' average out, and that on larger scales the exact position of all of those particles doesn't matter.

But here's the weird bit, it's not really about how complicated the system is, even three measly bodies are sufficient to make a system unpredictable. It's still deterministic, it's just not predictable... supposedly, not even by God Himself. So here's a question, in a system wherein the initial conditions are insufficient to predict an outcome... aren't deterministic and unknowable the exact same thing?

It's not predictable/knowable "to us", because it's just "far too complicated", etc. But we do know, and can see, that it must act/behave deterministically, because it follows certain mathematical rules and laws that even we can see and know enough about in order to say that it must behave deterministically, etc.

With our current math, we can see that it does/must behave or act deterministically, but also with our current level of math, it is also not nearly "high enough" for us to be able to predict/know it all deterministically, etc.

Don't know if those are the exact answers you are looking for, but there it is anyway.

God Bless.

 

[Bradskii]

So you're resorting to an argument from incredulity?

No, from impossibility.

You do realize that the number of particles is totally irrelevant? Because not only don't you know where all of them are... you don't know where any of them are. And it's not just that you don't know where they are, it's that nature itself doesn't know where they are. So how can reality possibly be deterministic, much less predictable, if it's impossible to know where anything is?

That would affect predictability, not determinism. We don't need to know where two billiard balls might be for them to act deterministically when they collide.

But here's the weird bit, it's not really about how complicated the system is, even three measly bodies are sufficient to make a system unpredictable. It's still deterministic, it's just not predictable... supposedly, not even by God Himself. So here's a question, in a system wherein the initial conditions are insufficient to predict an outcome... aren't deterministic and unknowable the exact same thing?

No. They are always different concepts. Unpredictable means that from an initial state you can't determine a future state. Unknowable means that you won't know the future state from the initial one but could mean that you'll never know it. Deterministic means that the future state cannot be other than what it will be.

 

[Occams Barber]

You do realize that the number of particles is totally irrelevant? Because not only don't you know where all of them are... you don't know where any of them are.

This was an example where @Bradskii was trying to explain how a system can be deterministic but unpredictable. In this case it explained how the sheer volume of information involved makes predictability impossible.

And it's not just that you don't know where they are, it's that nature itself doesn't know where they are. So how can reality possibly be deterministic, much less predictable, if it's impossible to know where anything is?

Who or what is this 'nature'.

Imagine a world without humans around to predict stuff. Would this lack of people to predict mean that it couldn't be a deterministic world?

The most repeated words in this thread are "Determinism and predictability are not the same thing!!!!"

Generally we do this by assuming that all of those 'unknowables' average out, and that on larger scales the exact position of all of those particles doesn't matter.

For true predictability down to the lowliest sub-atomic particle , averaging won't work. You need to know about the actual state of every particle.

o here's a question, in a system wherein the initial conditions are insufficient to predict an outcome... aren't deterministic and unknowable the exact same thing?

No. Lack of knowledge affects predictability but it does not affect determinism. A system does not cease to be deterministic because there's no-one around to predict.

Once again - determinism and predictability are not the same thing.

 

[Neogaia777]

For example, we do have some powers of prediction, like with chemistry, and chemical elements, etc. We can normally predict how certain elements are going to interact/react based on a certain set of conditions, etc, conditions that we try to make happen, etc, but that are all, or can be, all expressed mathematically, etc. The only exception to "normally" is only if there was something we didn't or couldn't know yet maybe on maybe the quantum level yet maybe, but only because we didn't know the math there yet realistically, which under certain conditions, could change it maybe, etc.

But just because we don't know, or don't understand, or can't fully comprehend, all of that math yet, doesn't mean it isn't there, because we know it is there, but just that we don't fully know all of it yet, etc, but it's all just essentially "math" basically, etc, which also means "so is all the rest of it that is made up of it", etc, even if it's just far, far too complex/complicated, or we don't fully know or understand all of it yet, etc. It can all, potentially, all be expressed and calculated/known/fully predicted by a mathematical calculation/equation, and we can see that much right now, etc. It's just that, right now at least, it's just way, way too complicated for us right now currently, etc. But we can see that it works/all will/does work that way, etc. Which means it's all, potentially at least, all fully knowable/predictable/expressable using mathematics, etc. Just not by us by a long shot right now, etc. But we can clearly see that it works/operates that way, etc.

God Bless.

 

[Neogaia777]

For example, we do have some powers of prediction, like with chemistry, and chemical elements, etc. We can normally predict how certain elements are going to interact/react based on a certain set of conditions, etc, conditions that we try to make happen, etc, but that are all, or can be, all expressed mathematically, etc. The only exception to "normally" is only if there was something we didn't or couldn't know yet maybe on maybe the quantum level yet maybe, but only because we didn't know the math there yet realistically, which under certain conditions, could change it maybe, etc.

But just because we don't know, or don't understand, or can't fully comprehend, all of that math yet, doesn't mean it isn't there, because we know it is there, but just that we don't fully know all of it yet, etc, but it's all just essentially "math" basically, etc, which also means "so is all the rest of it that is made up of it", etc, even if it's just far, far too complex/complicated, or we don't fully know or understand all of it yet, etc. It can all, potentially, all be expressed and calculated/known/fully predicted by a mathematical calculation/equation, and we can see that much right now, etc. It's just that, right now at least, it's just way, way too complicated for us right now currently, etc. But we can see that it works/all will/does work that way, etc. Which means it's all, potentially at least, all fully knowable/predictable/expressable using mathematics, etc. Just not by us by a long shot right now, etc. But we can clearly see that it works/operates that way, etc.

God Bless.

I may have confused some with part of this statement maybe, etc.

For example, with chemistry, if we know that if we change of alter the conditions so that certain chemical elements will act or react this way or that way, but we can't yet explain why it does that yet exactly, then we are probably changing something on some not fully understood level yet, more than likely on the quantum level, etc. But at all levels, it all goes/operates according to mathematical rules and laws, even if we don't fully understand all of those rules or laws yet, we know they are there, etc.

And mathematics is the language of determinism/predictability, etc. At least potentially anyway, etc. And we can at least see that much of it, etc. Even if right now, we don't fully understand/know absolutely all of it yet, etc.

God Bless.

 

[essentialsaltes]

But here's the weird bit, it's not really about how complicated the system is, even three measly bodies are sufficient to make a system unpredictable. It's still deterministic, it's just not predictable... supposedly, not even by God Himself.

No, the solution cannot be written in a closed form, but it is entirely deterministic and predictable (although sensitive to initial conditions, i.e. you need perfect knowledge of the masses, positions and velocities). Once again, the problem is our knowledge, not the nature of reality.

Using a computer, the problem may be solved to arbitrarily high precision

 

[partinobodycular]

No, the solution cannot be written in a closed form, but it is entirely deterministic and predictable (although sensitive to initial conditions, i.e. you need perfect knowledge of the masses, positions and velocities). Once again, the problem is our knowledge, not the nature of reality.

Ah, but here's the thing... it's not a matter of our lack of knowledge. It's inherent in the quantum nature of reality itself. We simply can't reach an arbitrarily high degree of precision. There are certain things about those particles that we simply can't know... because no such information exists. In purely mathematical terms, yes, an arbitrarily high degree of precision is simply a matter of assuming the necessary level of precision. But we exist in the real world, and we can't do that. Instead, we rely upon the fact that for the most part... close is good enough.

But, it's a mistake to assume that close is always good enough. Here's a question: The more complex that a system gets is it true that those initial conditions become less important or more important? For example, a double pendulum is notoriously susceptible to chaos, but what about a triple pendulum? Is it more susceptible or less?

Because it seems to me that determinism relies upon the size and complexity of the macro world to cancel out the inherent uncertainty of the quantum world. But to my way of thinking that's like assuming that I have free will simply because it seems like I have free will... it's the same as assuming that determinism makes reality predictable simply because it seems like it should make it predictable. When in fact we may have absolutely no way of knowing what's going to happen in the future.

 

[essentialsaltes]

Ah, but here's the thing... it's not a matter of our lack of knowledge. It's inherent in the quantum nature of reality itself.

OK, now that's much better. Yes, the standard interpretation of Quantum Mechanics is non-deterministic. And as far as we know, that means that the universe is not deterministic.

But that has nothing to do with free will or making choices. Whether a radioactive nucleus disintegrates in this second or the following one, or whether a state collapses this way or that, is not under conscious control.