Determinism

[Caecilian]

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Causal determinism is what it says it is. Its the doctrine that all phenomena are caused. In a Newtonian universe this would imply that the future is pre-determined (that there is only one future).

In both cases, 'one possible future' is incorrect, [...]

(my bolding)

What is the difference between the two boldings here? Because in the above bolding it seems that you agree with me that casual determinism means/implies that there is only one possible future. Whereas with the second bolding you seem to then contradict yourself and disagree with me.

Unless, I presume you mean that determinism itself is found to be incorrect by quantum mechanics and yet the definition (and the one I also use) of "only one possible future" is still correct?

To get more pedantic, you say that determinism ="that there is only one future", well what's the difference between that and "that there is only one possible future"? If it's the only, the one, possibility then that is the future so it's the same thing right? So I presume you agree with my definition (and I've only been arguing for the definition of determinism I've never argued for the truth of it - although I'd hope you realized that ).

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The first point that you bolded refers to the conditions in which 'one possible future' is correct. The second point draws attention to the fact that in 2 different interpretations of QM 'one possible future is false', despite one of those interpretations being deterministic.

To reiterate, there is only one possible future if:

1. Causal determinism is true

and

2. The many worlds interpretation of QM is false.

The point here is that causal determinism and 'one possible future' are separable. What the many worlds interpretation demonstrates is that its possible to have causal determinism and more than one future.

[Edwardo Piet]

Interesting how QM can change that.

I just can't understand then how a future is 100% determined and that then not be the only future. How is it 100% determined to happen if there are alternative futures? What's 100% predetermined about a future that can go many ways?

EvF

[Purple Rabbit]

To reiterate, there is only one possible future if:

1. Causal determinism is true

and

2. The many worlds interpretation of QM is false.

How do you exclude that there might be other descriptions of reality than Many Worlds that allow co-existence of causal determinism and multiple futures?

The point I was making is not about these descriptions being absolute true descriptions of reality but about logical neccessity: Many Worlds shows that there is no logical neccesity that fully deterministic descriptions imply one possible future. In other words, the very definition of determinism should not be overstated in that way.

[Caecilian]

To reiterate, there is only one possible future if:

1. Causal determinism is true

and

2. The many worlds interpretation of QM is false.

How do you exclude that there might be other descriptions of reality than Many Worlds that allow co-existence of causal determinism and multiple futures?

Good point. I'll amend that to:

2. Deterministic microphysical descriptions of reality which allow for multiple futures (such as the many worlds interpretation of QM) are false.

The point I was making is not about these descriptions being absolute true descriptions of reality but about logical neccessity: Many Worlds shows that there is no logical neccesity that fully deterministic descriptions imply one possible future. In other words, the very definition of determinism should not be overstated in that way.

Sure, your point about no logical necessity is very similar to my point about determinism and 'one possible future' being separable.

[Purple Rabbit]

I think mem is confused by all this.

[Caecilian]

I think mem is confused by all this.

Yeah, no doubt.

Unfortunately, philosophical concepts are rarely easy to explain.

And anyway, we've being talking about the philosophy of QM. Anyone who claims not to be confused by QM is lying.

[mem]

You guys are right. I am totally lost. So determinism is the theory(?) that everything that happens in the Universe is caused by all the other things that already happened and so it's like a chain of events. BUT. We don't know what the future is going to be so it's pretty useless to us unless we can understand how it works? Is that right?

[Purple Rabbit]

That's remarkably close to it considering you're just beginning the journey.

Some devils of the details:
- Determinism is not a scientific theory but a philosophical viewpoint. The difference is that determinism is not a body of scientifically coherent verifiable statements used to explain existing facts and predict new ones. Moreover determinism is a metaphysical statement about the nature of reality.
- Fortunately science gives us lots of verified theories with which we can predict quite a bit with good accuracy and understand historic facts.
- If determinism is true for the reality we live in it follows that contracausal freewill cannot exist. Since contracausal freewill is a concept that religious concepts as the soul depend on, it follows that determinism refutes religious concepts that are dependent on that.

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BTW, I think that the Reasonable Doubts podcasts are of excellent quality, especially these episodes:

rd64 - Determinator 4 - Rise of the machines
rd30 - FWvD2 - Judgement Day
rd29 - Free Willy vs The Determinator

[Caecilian]

That's remarkably close to it considering you're just beginning the journey.

Some devils of the details:
1. - Determinism is not a scientific theory but a philosophical viewpoint. The difference is that determinism is not a body of scientifically coherent verifiable statements used to explain existing facts and predict new ones. Moreover determinism is a metaphysical statement about the nature of reality.
2. - Fortunately science gives us lots of verified theories with which we can predict quite a bit with good accuracy and understand historic facts.
3. - If determinism is true for the reality we live in it follows that contracausal freewill cannot exist. Since contracausal freewill is a concept that religious concepts as the soul depend on, it follows that determinism refutes religious concepts that are dependent on that.

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Numbering added

Yeah, mem has done well. Sadly, I'm going to have to disagree with some of the above and no doubt muddy the waters again. Sorry mem.

1 and 2 are fine. 3 is problematic.

The issue for religious types isn't contracausal free will per se. Its the viability of libertarian free will, which is rather different.

Libertarian free will is the position that our conscious decisions (i) don't reduce ontologically to physical events, (ii) are causally efficacious and (iii) are somehow self-caused. Pretty clearly, libertarian free will requires an immaterial mind/ soul. I'm not sure that the reverse is true, though- which is what you appear to be saying. Since dualists need immaterial -> material causation for immaterial minds to affect the physical world, I'd assume that they also believe in immaterial -> immaterial causation. Which could be deterministic, I suppose (its all incoherent anyway, so why not?).

As I've said, the libertarian position requires that immaterial minds are somehow self-causing, or maybe not caused at all. This means that indeterminism is just as bad as determinism for the libertarian position. Mental states being the result of stochastic micro-phenomena is every bit as fatal to libertarianism as their being caused by deterministic micro-phenomena.

So why is libertarian free will so important to the christians? Not, I would say, because they need it for the soul to work. As noted above, for the soul to work you need immaterial causation (which is bad enough), but not immaterial self-causation, a concept that manages to be incoherent on two seperate counts (that takes doing). No- what they need libertarian free will for is the problem of evil.

The 'problem of evil' can be summed up like this: 'If god is so fucking benevolent, then why Auschwitz?'

The standard christian reply is: 'God gave Man free will. So he ain't responsible'.

This only works if the free will that god gave man is libertarian free will. If you don't accept libertarian free will then you get an uninterrupted chain of events that goes from god's creation to Auschwitz. The chain could be deterministic; it could be stochastic. It doesn't really matter. God gets the responsibility.

[Purple Rabbit]

You just add another religious concept, i.e. the dualistic idea that reality consists of material and immaterial or what I prefer natural and supernatural components, to the picture. But it does not change the validity of my statement. If reality (no matter whether it's the natural or the alleged supernatural component of it) is such that it does not allow contracausal free will, there is no room for a soul natural or supernatural that is uncaused.

Dualism as the dichotomy of natural and supernatural stuff is a troublesome concept for other reasons. For if the two are separate, how can they influence each other? I do contend that religious concepts that claim dualism have an additional problem. But even religions that don't claim duality and do claim independent ageny of souls have the problem I sketched above. So in fact the problem of contracausal free will in our reality is precisely the same as libertarian free will in our reality.

You seem to assume that when I speak of 'reality' I mean only the natural part of it, but that is not the case when I say "If determinism is true for the reality we live in it follows that contracausal freewill cannot exist". It's true that I can't extend a conclusion of physical determinism from the natural to the supernatural, but please observe that I haven't made such an assertion.

However if the religious assert that the supernatural is part of that reality and that souls are contracausal supernatural agents that affect the natural, it's up to the religious to show all of the following:
1) that the supernatural exists as part of reality
2) that the supernatural harbours contracausality
3) that the supernatural can affect the natural.

NB: I prefer natural vs supernatural because there indeed are things in the natural world (such as information and concepts) that are part of the natural world.