Imagining Determinism

[David Gould]

Must Y necessarily follow from X and not just "X must preceed Y"?

If it is a cause, preceeding something is not sufficient. However, this ties in with locality below.

Well, support then

What about locality? Would you have to study all agents anywhere in the universe?

Fortunately, the speed of light seems to allow us to discard a large number of agents. However, even if that were not so, the r squared law seems to enable us to discard many agents.

Of course, this depends on precisely what you are looking for. If you are looking for every single influence, no matter how small, you will certainly have to look at a very large number of agents.

However, much of the study of causes involves us looking for primary causes (the ones that have the largest impact) and immediate causes (the ones closest in time to the event).

Must there be some mechanism for A to influence B? Some interaction?

Force seems to be the way that this is described in science. Yes.

Ahh... I see. So when you say 'first cause', you don't mean First Cause (the universe), but rather you mean many effects which, themselves, do not have a cause. Is that about right?

Yes.

When I look up 'determinism' in Wikipedia, it just paints it as the opposite of Free Will, but it sounds like you're describing it as the theory that the universe is like clockwork, mechanical and predictable. But one of my problems is that, by acknowledging that the universe is not like clockwork because of QM, we have said nothing about Free Will, and so there must be more than simply this clockwork determanism and Free Will. What other philosophical options are there?

There is indeterminism.

I would go much further and observe that, in general, the universe is nothing like a clock in either the micro or macro scales. It is more like a waterfall, chaotic and roiling and predictable only only in terms of attractors and generalities.

I guess it depends on what you mean by 'nothing like a clock'. It also depends on where you are looking and what you are looking for.

For example if you are asking whether the universe is in general predictable in its behaviour, it is like a clock - science is all about predicting how the universe will behave.

However, I understand that not everything about the universe is predictable, even in a deterministic universe. There are emergent properties, for example. And there are practical limits on predictability, as you mention.

That is why I would suggest that determinism is most easily understood as the statement that there is only one cause that itself does not have cause (an alternative might be that there are no causes that do not have a cause - there is an infinite chain of causes).

However, indeterminism might be what you are after.

Practical determinism is what I accept.

 

[michabo]

Fortunately, the speed of light seems to allow us to discard a large number of agents. However, even if that were not so, the r squared law seems to enable us to discard many agents.

Interestingly, we know that entangled particles influence each other instantaneously across distance. The quantum world is unfortunately non-local.

There is indeterminism.

I guess that's a start, thanks.

I guess it depends on what you mean by 'nothing like a clock'. It also depends on where you are looking and what you are looking for.

I mean that the interesting parts of our universe are not predictable. That is, if everything lines up and goes through the same motions as before, the outcome will be different. If we can't predict outcomes, to what extent can we support causality?

Practical determinism is what I accept.

What's that?

 

[David Gould]

Interestingly, we know that entangled particles influence each other instantaneously across distance. The quantum world is unfortunately non-local.

Yes, I accept that. But in the vast majority of cases influences like that are extremely limited, if they exist at all.

I guess that's a start, thanks.

I mean that the interesting parts of our universe are not predictable. That is, if everything lines up and goes through the same motions as before, the outcome will be different. If we can't predict outcomes, to what extent can we support causality?

But we can predict outcomes - perhaps not exactly, but that is simply a practical limit.

In other words, we can predict many, many things about our universe. Even with regard to quantum mechanical interactions, we can make statistical predictions that are 100 per cent accurate - we can predict the spread of data exactly.

Can we 100 per cent support causality? No. However, the fact that we can predict anything at all gives us reason to believe that causality operates in the universe.

What's that?

That while the universe is not actually deterministic if you operate as if it does you will not go too far wrong. (I accept that if you are working in the field of quantum mechanics this might not be too useful a maxim to follow, but you get the idea )

 

[levi501]

The double slit experiment is not the end of QM. There is much more to it than that. It has been demonstrated mathematically that QM behaviour is not caused.

Can you link me to anything that might explain this, because honestly it sounds illogical to me and I understand that this is due in part to my ignorance on the topic. It baffles my mind to consider that if time was rewound something else could occur.

 

[David Gould]

http://www.ncsu.edu/felder-public/kenny/papers/bell.html

This does not discuss randomness directly, but it shows why quantum mechanics destroys locality, damages the notion of causality and relys on randomness to make its predictions. Bell's inequality is the most famous and disturbing aspect of quantum mechanics.

Einstein was completely against the randomness idea of quantum mechanics - 'God does not play dice!'. He published a paper - the famous EPR paper (Einstein, Podolsky, and Rosen - the authors) - that showed that quantum mechanics was incomplete (ie, must have hidden causation).

Bell's theorem, and the experiments which tested it, showed that Einstein was wrong.


This is the EPR paper:
http://www.drchinese.com/David/EPR.pdf

This is where I got it from:
http://www.drchinese.com/David/EPR_Bell_Aspect.htm

Aspect was the guy who did the experiments to prove Einstein wrong.

The reason that non-locality proves Einstein wrong is basically because locality was the key assumption that Einstein made to demonstrate that QM had to have hidden variables and be caused, not random.

There have been and still are attempts to get rid of non-locality, but none have been able to get round Bell's theorem.

 

[David Gould]

http://math.ucr.edu/home/baez/physics/Quantum/bells_inequality.html

This is an interesting paper from that same page - it is suggesting that the issue is not completely dead as yet.