Does Physics disprove the existence of free will?

[Write4U]

My decision to walk through the space was only made because the car departed (left) the space. Free-will!

You decided to take the Path of least resistance! But is that freely chosen?

 

[Write4U]

In my thread where I assume that the conscious mind would be the state of a group of neurons, he claimed that the same state of a group of neurons at two different times might not necessarily result in the same outcome, outcome that could be for example what a person does.

I see nothing controversial in that statement. Key-word: "at two different times" (including the potential implications of that qualification).

The real question is if one could have done differently, ever, if the state of a group of neurons and the times were the same, IOW, "could have done different".

IMO, the answer to that is "no" as it can never be proven that someone did other than what they would always do, without the introduction of a variable.
Introducing a variable results in a variable answer, but does not prove that one could have done different than what they did, at another time.

 

[Baldeee]

I have made no other argument than my postings include, and they include no such idiotic "conclusions", or any reasoning that would lead to them. You are not paying attention.

I am paying attention, iceaura, and you're starting to sound like Jan Ardena.
Just because you don't explicitly set out a conclusion does not mean that there are not other logical conclusions to what you have said.
You are responsible for the logical implications of what you say, whether you explicitly say them or not.

Your "original formulation" (early posts? whatever) contained no situation, example, or hypothetical, that was not physically deterministic.

But it didn't specifically exclude them, did it.
Unless one makes the premise that everything is deterministic then it allows for the non-deterministic.
If you wish to work from the assumption that everything is deterministic, that is an added assumption by you.

You have alluded to their existence, but presented none - possibly for the very good reason that they are irrelevant here.

They are certainly irrelevant to the case of the strictly deterministic universe that the discussion then went on to specifically consider.
But not to the original formulation that I set out.
And it is not for me to provide example of them, only that the logic does not exclude their possibility.
It gives room for someone to, for example, dispute premise 3, that the will is a system built from deterministic interactions.

Your argument concerned deterministic setups only, as specified in your premises.

And you accuse me of not paying attention.
Re-read post #130, iceaura.
All the premises do is refer to deterministic interactions and systems built from them.
It does not exclude the possibility of non-deterministic interactions within the universe.
Just as the syllogism regarding Socrates does not exclude the possibility of women within the universe.

It's the OP setup, as well, and that of every single post by everyone else here. Other situations have not come up, and if they did they would be completely irrelevant to my posting and any replies to my posting.

No, the OP setup is regards the many-worlds theory, which for a given world is indeterministic, and only when considering all worlds can it be considered deterministic.
Again, you accuse me of not paying attention.

Now you are being silly: The degrees of freedom are observed - not "felt" or "thought". If you leave them our of your calculations you will get wrong answers even about bricks and Teslas, let alone more complex systems, as even the most elementary of educations in statistics will teach you.

I don't disagree that the degrees of freedom are observed, and can be detailed.
But our interpretation of what is observed as being an actual ability to do otherwise is indeed a "thought" or a "feeling".
Just as when we see a magician perform a trick, we think we are observing something impossible rather than actually observing something impossible.

Yes. If you don't, you will say very stupid things - such as that the ability to make decisions based on criteria is an illusion that humans have.

You are now misrepresenting my position and my argument.
I do not say that the ability to make decisions is an illusion - the decision making is a process we have, this is not disputed.
What I consider illusory is that this process offers a genuine ability to do otherwise.

You are claiming, with a straight face, that decisions are never made because the universe has predetermined what they are going to be.

No, I am saying that the process of decision making is undertaken, but that it has no more a genuine ability to do otherwise than any other deterministic system ultimately has.
I.e. zero.
So please pay attention with regard what I'm saying.
I know it's easy for you to argue strawmen, but I'd appreciate it if you don't.

Slippery (remember the quantum switch - we're dealing in information, some of which is inherently unknowable),...

Now you are crossing between discussing the deterministic universe and indeterministic.
You seemed to think previously that we are merely discussing the deterministic universe, so why bring in issues of quantum indeterminism?
Please stick to one or the other.

... and remarkably arrogant about what other people feel and think...

Not at all, I'm merely stating the logical conclusion of the argument.

- but doesn't matter except as a clue to where you are about to step on your dick, which is right here:
Uh, no, it's not. It's a physical fact. A decision is a physical event that has consequences. The ability to make a decision is no more an illusion than the ability to walk.

And once again you demonstrate that you haven't been paying attention.
The argument is not that there is no process that we call "making a decision".
As you say, there is such a process.
It is a physical fact.
The same way that any computer process is a physical fact.
The process is not what is being referred to as an illusion, but the notion that the process offers the ability to do otherwise.

So?
That's irrelevant to my posting, including my objections to your arguments above.
Read carefully, please:

It is relevant because you accused that the initial formulation I presented included the assumption that freewill was supernatural.
I have on several occasions, and quite clearly, demonstrated that this is not the case.
The fact that the discussion shifted to specifically the case of the deterministic universe is irrelevant to those initial accusations, and the ongoing accusations regarding that initial formulation.

 

[Baldeee]

It's been a while, but I'll dip a toe back into this discussion. It seems that Baldeee and Sarkus both remain stuck on the same point.

Neither of us are stuck, JamesR.
We both seem to be at our destination and enjoying the view.
You seem to be assuming that our destination is elsewhere and thus see us as stuck.
That is your mistake.

Okay. Let's run with what you say. In your picture, tell me how could free could possibly be anything other than supernatural.

You've told us that you assume that you define "freedom" in this context to mean "the ability to do otherwise". You've also told us that you assume that no deterministic system can have "freedom" of this type. You've told us you assume that acts of will are deterministic. You've told us that you therefore conclude that acts of will have no "freedom" in the relevant sense. Case closed, you tell us.

So, running with your argument, there can be no free will unless one of your premises has a hole in it. Agree?

Could it be that acts of will aren't deterministic?

It could be, yes.

iceaura has all along conceded that they are (and I do too, for the purposes of this discussion).

He has said as much, but within the deterministic universe that he has been focussing on there is no indeterministic process.
Yet he still thinks that free will (or the ability to do otherwise) exists within a deterministic universe.
He wants his cake and to eat it.

Although you keep questioning him on this point, as if he had ever said anything different, it is clear that he and I both agree with you that acts of will are deterministic. So, that premise in your argument is solid (or, at least, undisputed in this discussion). Agree?

Not quite.
While he has certainly stated that they are deterministic in as much as if you reran the situation again you'd get the same outcome, he doesn't seem to comprehend the predeterministic nature of a deterministic universe.
I.e. that the outcome of the decision was set in stone at the outset of time (assuming a universe that was always deterministic).

Your only other premise...
...
The only puzzle that remains is why both of you keep denying that you regard the supernatural as the only possible way the will could be free.

You'll excuse me for snipping out the bulk of your post... lack of time on my part... and I may get back to it.
However, this last question is important.
My answer is categorical that in a deterministic universe the only way the will could be free is via supernatural means.
This has never been disputed by me, by Sarkus, by DaveC etc.
What has been disputed is that we assume it from the outset, as iceaura accused.
We don't.
It is the conclusion of the logical argument.
The premises are accepted, the logic valid, and thus we conclude that the ability to do otherwise in a deterministic system must either not exist or it must exist via the supernatural.
That it is a conclusion is not disputed.
That it is an assumption from the outset is.

 

[TheFrogger]

If free-will is supernatural, then how is it originally formed, if not by the subject???

 

[James R]

Baldeee:

Just to be clear, I'm in complete agreement with iceaura in this discussion. That is, I agree that his assessment of your stance and that of Sarkus in this discussion is correct.

It is unfortunate that you chose to ignore the vast majority of my last post to you at this stage, since what I wrote there is really the crux of the dispute. Nevertheless, what you've written in reply is useful, so let's see where that gets us.

It could be, yes.

Okay, so the focus of much of the argument to this point has been on what you have labelled the "argument from determinism" (or was that Sarkus's label?). But now you're saying that maybe the will isn't deterministic after all. If that's the case, then your argument from determinism becomes irrelevant and a new question arises: is there any mechanism in the universe that would allow the will to act non-deterministically, other than a supernatural one? Got any suggestions? Bear in mind that we've already decided that quantum indeterminacy, being essentially random, won't allow free choice, because a random selection among alternatives is not an exercise of will.

He has said as much, but within the deterministic universe that he has been focussing on there is no indeterministic process.

iceaura has been discussing only deterministic processes because you and Sarkus have been arguing with him only about your Argument from Determinism. In the context of that argument, as set out by you in syllogistic form, non-deterministic processes are irrelevant. Why would iceaura want to discuss something that is irrelevant to the point of dispute you have with him?

Yet he still thinks that free will (or the ability to do otherwise) exists within a deterministic universe.

As do I. This is the point of contention. You and Sarkus claim that there can be no free will in a deterministic universe. iceaura and I claim there can be. Non-deterministic universes are a separate topic that is probably best discussed in detail after we sort you and Sarkus out regarding the deterministic case.

He wants his cake and to eat it.

You and Sarkus are arguing that determinism and free will are incompatible. iceaura and I hold that they are compatible. iceaura has spent a lot of time trying to show the two of you that the unstated assumption you and Sarkus share is that an act of will can only be free if it breaks the laws of physics (i.e. is supernatural). Your justification for incompatibilism in a deterministic universe is only to be found in the assumption that true "freedom" of the will would require breaking the laws of physics so as to cause a different output for identical inputs, as you put it.

It sounds like your fall-back position is that, maybe different outputs (decisions by a human being) might be possible for identical inputs if there is some kind of unspecified natural non-deterministic process in play, and that might save free will. The challenge for you, in that case, is to suggest a natural non-deterministic process that would enable the required behaviour. If there isn't one, then we're back to supernatural processes if we are to have any free will.

While he has certainly stated that they are deterministic in as much as if you reran the situation again you'd get the same outcome, he doesn't seem to comprehend the predeterministic nature of a deterministic universe.
I.e. that the outcome of the decision was set in stone at the outset of time (assuming a universe that was always deterministic).

I think iceaura comprends that just fine, as do I. You're confusing the question of the "ability to do otherwise" of the universe as a whole with the "ability to do otherwise" of the human about to make a decision whether to stop at the traffic light. These are abilities that are acting at different levels of abstraction and complexity.

This is something I discussed at length in the part of my previous post that you ignored. Rather than repeat it, I'll give you a chance to digest it and to respond.

My answer is categorical that in a deterministic universe the only way the will could be free is via supernatural means.

It seems to me that this is an observation that iceaura has been making over and over about your deterministic argument, but which you and Sarkus have kept denying. But now you admit that, according to you, there's no free will in a deterministic universe except via the supernatural. In other words, free will is incompatible with determinism, according to you.

iceaura and I both hold the position, in contrast, that free is entirely compatible with determinism. We do not feel that we need to resort to the assertion of a non-deterministic universe in order to account for the "apparent" free will we all feel. We say that we have free will, despite the deterministic universe. In all the ways that it matters for the will to be free, our will is free. The fact that it is determined doesn't remove the relevant freedom. The questions of determinism and freedom are two different questions. You and Sarkus, on the other hand, conclude that determinism is equivalent to non-freedom of the will. This is because the only possible freedom you will allow in your deterministic universe is supernatural freedom. No other kind of freedom counts, for you.

What has been disputed is that we assume it from the outset, as iceaura accused.

It's the only way you can get to the conclusion of "no free will" from your deterministic argument - to assume that freedom in a deterministic universe requires the supernatural. That's an assumption. Unstated, but it's there. If you leave out that assumption, you can only conclude that a person has no "ability to do otherwise" in a deterministic universe, and the question of freedom of the will isn't even addressed.

It is the conclusion of the logical argument.
The premises are accepted, the logic valid, and thus we conclude that the ability to do otherwise in a deterministic system must either not exist or it must exist via the supernatural.

See what I mean? How do you get from "there is no ability to do otherwise in a deterministic universe" to "there's no free will in a deterministic universe"? The answer lies in your description of free will, which is an unstated premise of your argument. Everything that you and Sarkus have said implies that your definition of "free will" requires the supernatural, working in the deterministic universe framework.

If we're clear on this point now, then we can move on to discussing your non-deterministic universe suggestion, and whether natural free will might be possible in such a universe, according to you.

 

[Baldeee]

Right, back to tackle part 2...

Your only other premise is that no deterministic system ever displays "the ability to do otherwise". This would therefore appear to be the point of contention in the debate. So, we need to carefully unpack what you mean by "the ability to do otherwise". Relevant questions include:

• When, exactly, does the "ability to do otherwise" become relevant in an act of will? Before the decision is taken (and, if so, how long before)? During the making of the decision? Once the consequences of the decision have become apparent?
• How are we to distinguish a real "ability to do otherwise" from merely an apparent "ability to do otherwise"? After all, we all apparently think we can either stop at a traffic light or drive through it.
• Would the "ability to do otherwise" require that the laws of physics be broken?

Taking them in turn:
1. The ability to do otherwise is relevant throughout the process.
Just as a train can move one way or another if that is the way the tracks go, it is still on the tracks, and still not free to move off them.
The fact that you can look ahead and see it moving one way or another doesn't change that.

The argument that you (Baldeee and Sarkus) have been running in this thread is that a person deciding (carrying out an act of will) whether to stop at a traffic light or drive through it never has "the ability to do otherwise" at any relevant time.

Correct.
They have the belief / feeling / sense that they do.
But every moment (in a deterministic universe) is predetermined, including every moment of the decision making process.

Let's look at the timing issue. Before the decision, you would presumably tell us that the atoms in the person, the electrical impulses in the brain, the atoms in the traffic light and so on, are all inevitably rushing towards the point where they "make" the person choose either to stop or go.

Yes, but each moment is like that, not just the decision making "moment" but every moment leading up to it and every moment beyond that.

This is dictated by the laws of physics. At the point of decision, the worldlines of all the relevant particles converge to produce a mental state in the human driver that is totally determined by the past configurations of the relevant particles. After that time, the particles continue their merry dance, as dictated by the physics, and the driver inevitably either hits the brake or the accelerator. During this whole process, the driver's mind is inevitably reconfigured so that he believes, after the event, that he made a "free" choice to stop the car (or not).

I wouldn't say it is reconfigured as that implies that it was a different way beforehand.
I would simply say that during the process the conscious mind has the sense that it is "free".

We might ask the following question of the driver: "What caused you to stop the car?" He would tell us a rationalisation of the sequence of events that would somewhere, no doubt, include words like "... and then I decided to stop" or whatever. Are we to take this at face value, being the smart people we are? No! Pull out the electrotrodes and fetch the machine that goes "ping" to measure his brain waves as the decision is made. Oh look! The brain analysis shows the act of making a decision. How about that? His brain actually made a decision.

No one disputes that the brain went through the process of making a decision.
A computer does just that as well - and it can be monitored, recorded, observed as well.
The question, for the umpteenth time, is not whether there was a process we call "making a decision" but whether that decision is actually free.
If you can't stick to that, and feel the need to keep confusing the issue with whether the process of making a decision occurs or not, then you're being irrelevant.
And I've gotten more than enough of that from iceaura.

But was that the "real" cause of stopping the car? How about the following explanation instead: "In the beginning, there was a big bang, then came recombination, and ...[insert billions of years of detailed specifications of particle behaviour] ... and then the car stopped."? What happened to the act of will in that explanation? Where did it go? Are we still talking about the will at all, in this explanation?

Of course we're still talking about the will.
But it gets you no nearer to showing how the will is actually "free".

Let's not confuse freedom of the "universe" to do other than it must with freedom of an individual human being to make a choice. We need to discuss this at the right level.

I am discussing at the right level, James.
From the outset it has been accepted that if you/others simply want to talk about the sensation of freedom that we experience, go ahead, noone is stopping you.
I, Sarkus, and presumably others, are more interested in whether that sensation is more than just the sensation of being free but is actually free.
And per the logic, it isn't.
It would seem, in a deterministic universe at least, to be just a sensation.
That is the level I'm discussing.
If you don't want to, and you want to ignore this level, you know where the door is.

This brings us to the second issue: in making his choice to stop the car, was the driver making a "real" choice, or was he under some kind of mistaken impression, due to an illusion created by all those dancing particles, that he was making a choice? Did he have a real "ability to choose to stop", or merely an apparent ability to choose to stop? If his stopping the car was not due to his actual choice, whose choice was it? Was there any choice at all?

Of course there was a choice.
In as much as his brain went through a process that we refer to as "making a decision" or "choosing".
In the predetermined nature of the deterministic universe, if you throw a black box over a chunk of the interactions and call it "choice" you don't change the nature of the universe, or the fact that everything is predetermined.
If you also only consider part of the overall system, as Sarkus was at pains to explain to iceaura, you can even get what appears to be an indeterministic system in a deterministic universe.
But this would be only an illusion, due to not considering all the relevant elements.

It seems to me that it is meaningless to talk about the driver's decision in any way other than saying he made a choice. If that was not what was happening there, at the relevant high level of description, then what was happening? It would make a mockery of the language to say that the driver did not choose what action to take, in my opinion. All the relevant evidence - the only available evidence - says that the driver made a choice, or else the word "choice" itself is meaningless.

I don't dispute what you say in any other context than when discussing the philosophy of it.
Pragmatically one can only go by what we experience, and not even look under the hood, so to speak.
Our language is based upon that.
But that doesn't stop us, or at least shouldn't stop us, examining what is under the hood.
And if our experience suggests we are "free" but the workings under the hood say otherwise... then we have discussions such as this, where some are content with the experience, and some lift the hood.

At this stage, the questions are as follows:
1. Do you (Baldeee and Sarkus) agree that the driver made a choice to stop (or not to stop)?
2. Do you agree that the car's stopping (or not) was a direct result of the choice that the driver made?
3. Would it be fair to describe the driver's will (as expressed through his choice) as a proximate cause of the car's stopping (or not)?
4. Do you agree that, if the driver had made the "opposite" choice, the outcome would have been the opposite to the one that was actually observed?

Bear in mind that we could repeat this experiment many times and ask the same questions.

I can of course only speak for myself, but to answer:
1. Yes
2. Yes
3. Yes
4. "If", yes, but the question is whether he was free to make such a choice other than the one he did at the time he made it.
And that includes all the moments previously when he made similar choices not to stop.

To be continued....

 

[Baldeee]

Part 3...

I would like you to answer all four questions. I would like to assume that your answers to all of them would be "yes", but you never know. If you answer "yes" to all four questions, then we can move on to the final step.

Then let's move on.

The third and final question is whether actually having the "ability to do otherwise" would require the driver to break the laws of physics. Notice, by the way, that question 4, above, says nothing about breaking the laws of physics. It speaks only to outcomes.

It also speaks to having a possibility of making the "opposite" choice.
That is rather begging the question.
While I have no doubt we can imagine a future where that opposite decision is taken, the question is whether at the time of making that decision the driver could have done anything else other than what they did.
They will likely have the sensation that they could have done something else.

Let's say that, in one observed instance of this experiment, the driver chose to stop the car at the light. If you hold that he could not conceivably have chosen to go through the light, other than by breaking the laws of physics, then it would seem obvious that you hold the opinion that the "ability to do otherwise" would require a supernatural intervention.

There are many issues with this set up of the experiment, as each time you run it you will not be starting with the exact same setup.
You might think you are: after all you have can have the same driver, same lights, same speed, same timings... but the starting conditions will still be different each time.
If you did start with the exact same starting conditions then the deterministic nature of things would mean that the same outcome would be achieved.
But if you don't start with the exact same starting conditions then the outcome might not be the same.
And yes, in a deterministic universe to do so would require a supernatural intervention.
Thus it doesn't happen as far as I am concerned, as I don't consider the supernatural.

The rest I have answered previously.

 

[Baldeee]

Just to be clear, I'm in complete agreement with iceaura in this discussion. That is, I agree that his assessment of your stance and that of Sarkus in this discussion is correct.

Then you are mistaken as well, but never mind.

It is unfortunate that you chose to ignore the vast majority of my last post to you at this stage, since what I wrote there is really the crux of the dispute. Nevertheless, what you've written in reply is useful, so let's see where that gets us.

As said at the time, I would try to get round to it, and I have. So no, I didn't ignore it then, nor have I since.

Okay, so the focus of much of the argument to this point has been on what you have labelled the "argument from determinism" (or was that Sarkus's label?). But now you're saying that maybe the will isn't deterministic after all.

The argument premises that it is, but someone can happily challenge that premise.
Do you want to?

If that's the case, then your argument from determinism becomes irrelevant...

No, it is relevant as long as one considers the premises sound.
If you don't then the argument, no matter how valid, is unsound.
Whether you then wish to consider an unsound argument as irrelevant is up to you.

... and a new question arises: is there any mechanism in the universe that would allow the will to act non-deterministically, other than a supernatural one? Got any suggestions?

QM is non-deterministic, at least in most interpretations, for example.
As for others, I am not aware of any but I don't know for sure whether might be or not.

Bear in mind that we've already decided that quantum indeterminacy, being essentially random, won't allow free choice, because a random selection among alternatives is not an exercise of will.

Yes, I would agree, but others might not.
But note that me not being able to provide examples of non-deterministic (or probabilistic) mechanisms does not mean that I assume that there are none.

iceaura has been discussing only deterministic processes because you and Sarkus have been arguing with him only about your Argument from Determinism.

Yet in his discussions he arrives at indeterministic processes: the ability for the same initial conditions to lead to different outcomes.
That this is where his comments and argument lead is something he seems to be struggling with.
In a deterministic universe, if you think you have the same initial conditions but a different output then you are not talking about the same conditions initial conditions, but rather just a sub-set of the conditions.
And if the sub-set of the conditions are not determining the outcome (i.e. are not always leading to the same outcome) then something else is that is not being considered.

In the context of that argument, as set out by you in syllogistic form, non-deterministic processes are irrelevant. Why would iceaura want to discuss something that is irrelevant to the point of dispute you have with him?

I have no issue with the fact that he wants to only discuss the case of the deterministic universe.
The issue was with regard the accusation that the argument itself assumed the supernatural nature of "free".
It didn't.
The supernatural nature of "free" would be a conclusion, not an assumption.
There's only so many ways that I, or Sarkus, or anyone else, can explain that to you/him before it becomes obvious that your blockage in this regard is outside our ability to clear.
I think I'm well past that stage with iceaura.

As do I. This is the point of contention. You and Sarkus claim that there can be no free will in a deterministic universe. iceaura and I claim there can be. Non-deterministic universes are a separate topic that is probably best discussed in detail after we sort you and Sarkus out regarding the deterministic case.

Wow, the hubris is deafening, JamesR.
Sort us out?
Really?
And I agree, non-deterministic universes are a separate topic entirely.

You and Sarkus are arguing that determinism and free will are incompatible. iceaura and I hold that they are compatible. iceaura has spent a lot of time trying to show the two of you that the unstated assumption you and Sarkus share is that an act of will can only be free if it breaks the laws of physics (i.e. is supernatural).

And both Sarkus and I have shown you quite unequivocally that there is no such assumption, any more than there is the assumption that Socrates is mortal.
There is the conclusion, at least in a deterministic universe - where all processes are deterministic.

Your justification for incompatibilism in a deterministic universe is only to be found in the assumption that true "freedom" of the will would require breaking the laws of physics so as to cause a different output for identical inputs, as you put it.

Again, there is no such assumption.
What you refer to is the conclusion!

It sounds like your fall-back position is that, maybe different outputs (decisions by a human being) might be possible for identical inputs if there is some kind of unspecified natural non-deterministic process in play, and that might save free will.

Yes, it might.

The challenge for you, in that case, is to suggest a natural non-deterministic process that would enable the required behaviour.

No, that would be the challenge of anyone who wishes to argue that, and question the soundness of the premise that the will is a deteremined process.

If there isn't one, then we're back to supernatural processes if we are to have any free will.

Indeed, that is the conclusion of the argument.
Please do not refer to it as an assumption.

I think iceaura comprends that just fine, as do I. You're confusing the question of the "ability to do otherwise" of the universe as a whole with the "ability to do otherwise" of the human about to make a decision whether to stop at the traffic light.

No, I'm not.
For you to even talk about "the universe as a whole" suggests that you believe small pockets of indeterminism can arise within the deterministic universe.
Is this what you believe?
Otherwise, for any deterministic system, whether that is the universe as a whole or any other deterministic process, the conclusion is the same.

These are abilities that are acting at different levels of abstraction and complexity.

Nice handwaving, JamesR.
Unfortunately it doesn't get you past the issue that any deterministic system lacks the ability to do otherwise.
If you accept that this is true of the universe (as a system) then on what grounds do you deny it of any other deterministic system?

It seems to me that this is an observation that iceaura has been making over and over about your deterministic argument, but which you and Sarkus have kept denying. But now you admit that, according to you, there's no free will in a deterministic universe except via the supernatural. In other words, free will is incompatible with determinism, according to you.

Do you understand the difference between an assumption and a conclusion?
It doesn't seem like it at the moment.
I have been quite clear that the conclusion is that the ability to do otherwise ("free") is incompatible with determinism, and thus to be "free" must be supernatural.
Iceaura's "observation" is that the argument assumes that to be free must be supernatural.
Do you see the difference?

iceaura and I both hold the position, in contrast, that free is entirely compatible with determinism. We do not feel that we need to resort to the assertion of a non-deterministic universe in order to account for the "apparent" free will we all feel. We say that we have free will, despite the deterministic universe.

We all say we have "free will" but the question is whether it is actually free, or whether that is an illusion.

In all the ways that it matters for the will to be free, our will is free.

Noone disputes that.
Because it doesn't matter to us (practically speaking) that our will is not actually free.

The fact that it is determined doesn't remove the relevant freedom.

Agreed, that "relevant freedom" being the mere sensation of it.

The questions of determinism and freedom are two different questions.

You mean other than determinism meaning a universe that is entirely predetermined?
Where our every action is set out in stone, unchangeable?
Yep, nothing to do with freedom at all.

You and Sarkus, on the other hand, conclude that determinism is equivalent to non-freedom of the will. This is because the only possible freedom you will allow in your deterministic universe is supernatural freedom. No other kind of freedom counts, for you.

It's not that no other counts but that, when looking at "the ability to do otherwise", how else would you describe a predetermined path as being one where you have no ability to do otherwise?
Oh, unless you go merely by the sensation that we are able to.
Which is what we do on a day-to-day basis.

To be continued...

 

[Baldeee]

Part 2... of this one, anyway.

It's the only way you can get to the conclusion of "no free will" from your deterministic argument - to assume that freedom in a deterministic universe requires the supernatural.

That's an assumption. Unstated, but it's there. If you leave out that assumption, you can only conclude that a person has no "ability to do otherwise" in a deterministic universe, and the question of freedom of the will isn't even addressed.

???
The "ability to do otherwise" is what has been considered "freedom".
So if you accept that without the so-called assumption that all I can do is conclude that a person has no freedom in a deterministic universe, and I am telling you that what I am doing is concluding that in a deterministic universe a person has no freedom... what is your issue, and why are you trying to insert the additional assumption?

See what I mean? How do you get from "there is no ability to do otherwise in a deterministic universe" to "there's no free will in a deterministic universe"?

Noone disputes the existence of a process of "free will", or "choice" etc.
The issue has always been one of whether that process is free, i.e. whether the process offers an "ability to do otherwise".
You have agreed just above that without the so-called assumption I can only conclude that a person has no "ability to do otherwise".
Well, whodathunkit!
That's exactly what I've been concluding all along.
Not the non-existence of a process but the non-existence of that process granting us an ability to do otherwise.

The answer lies in your description of free will, which is an unstated premise of your argument. Everything that you and Sarkus have said implies that your definition of "free will" requires the supernatural, working in the deterministic universe framework.

No, it doesn't.
You are simply confusing the process called "free will" with that process being "free".
But hopefully now that you have, finally, accepted that all the logic can conclude is that a person has no such ability to otherwise, this matter (regarding the so-called assumption) is now closed?
Or is that just too much to hope for?

If we're clear on this point now, then we can move on to discussing your non-deterministic universe suggestion, and whether natural free will might be possible in such a universe, according to you.

Oh, we're far from clear, JamesR.
First question for you, for the sake of clarity: do you accept that in a deterministic universe, as argued, the conclusion is that a person has no "ability to do otherwise"?

 

[Write4U]

Question: Is "choosing the least of two evils" a free will choice? The ability exists, no?

If so: Is "choosing the least of two goods" a free will choice? The ability exists, no?

 

[iceaura]

You are responsible for the logical implications of what you say, whether you explicitly say them or not.

I'm not responsible for anything you decide to claim is a logical implication of my posts.

Just because you don't explicitly set out a conclusion does not mean that there are not other logical conclusions to what you have said.

And it doesn't mean there are.
Meanwhile: if you haven't dealt with or even recognized the conclusions that were explicitly set out, the arguments that were made, you haven't actually replied to the post.

QM is non-deterministic, at least in most interpretations, for example.
As for others, I am not aware of any but I don't know for sure whether might be or not.

As stipulated repeatedly over many pages here, both explicitly and by direct implication, the kind of "indeterminacy" supposedly introduced by quantum and chaos theory is not relevant here. No one - least of all you - has presented any physical loopholes through which human mental behaviors - macroscopic and slow and brief as they are - can escape being physically deterministic. So there is no loss in stipulating to the circumstance, and the entire thread has, throughout.

It also speaks to having a possibility of making the "opposite" choice.

Not "possibility" from an omniscient view of the entire lifespan of the entire universe (that's not at issue): "Ability" , from current observation of the deciding entity. Degrees of freedom in its action (decision making), which it possesses at the moment.

That is rather begging the question.

Yes. Quit doing that.

In the predetermined nature of the deterministic universe, if you throw a black box over a chunk of the interactions and call it "choice" you don't change the nature of the universe, or the fact that everything is predetermined.

But you do observe the physical nature of the entity that the universe - not you - has thrown that "black box" (human finite lifespan and knowledge) over. This nature is not an illusion. It is intersubjectively verifiable, theoretically describable, repeatably demonstrable, scientific fact.
The freedom of will of the universe entire is not the matter at hand. Consider the analogy with the 2nd Law.

 

[Quantum Quack]

Every thing a human does is about determining his own future. He is an organic determining machine evolved to be that determining machine by a deterministic universe.
What is so hard to accept about that?

 

[James R]

Baldeee:

Thanks for your detailed replies. It seems you're still not quite getting the point, so I'll try again. I'll start at the end and then try to go back to tie up some loose ends.

It's the only way you can get to the conclusion of "no free will" from your deterministic argument - to assume that freedom in a deterministic universe requires the supernatural.

That's an assumption. Unstated, but it's there. If you leave out that assumption, you can only conclude that a person has no "ability to do otherwise" in a deterministic universe, and the question of freedom of the will isn't even addressed.

???
The "ability to do otherwise" is what has been considered "freedom".

Here's how you originally put your premises:

P1: if something is determined then it can not do other than it must.
P2: systems built from determined interactions are themselves determined.
P3: the mind and will are systems built from determined interactions.

Conclusion [C1:] the mind and will can not do other than they must.

First thing to realise is that none of this is disputed. As far as this goes, it is fine. But notice that the words "free will" don't appear anywhere in the premises or conclusion. And that's what we're supposed to be talking about, right?

If you want to draw the additional conclusion that "there is no free will in a deterministic universe" you need some additional premises.

One possible premise might be:
P0a: Something is not free if it is determined.

Then we could conclude:
C2a: The mind and will are determined (follows from P1 to P3).
C3a: The will is not free (follows from P0a and C2).

That would be a bad argument, though, P0a begs the question. We're trying to establish whether there is free will in a deterministic universe. We can't start with the supposed conclusion as an assumption.

You therefore suggest the premise:
P0b: Something is free if it has the ability to do otherwise.

With this premise, you would presumably like to draw the conclusion:
C2b: The will has no ability to do otherwise.
C3b: The will is not free (follows from C1 and C2).

But you can't get to C2b from premises P1 to P3, since those premises make no mention of any "ability to do otherwise", which is about choice (an "ability") and not (as in P1) about a system doing as it must. You need another premise, or another argument. The additional argument you're now running looks something like this:

P4b: If a system is built from determined interactions, then it has no ability to do otherwise.
C2b: The will has no ability to do otherwise (follows from P4b and P3).
C3b: The will is not free (follows from P0b, C1 and C2b).

We have previously touched on two ways in which we agree that argument (which includes the added premises P0b and P4b) could fail, both of which occur when P3 turns out to be false, after all. That is, the conclusion that there is no free will would not follow if it turns out that the will is a system built from indeterminate natural interactions, or if the will is a system built on supernatural interactions (also undetermined). We agree that in both cases the argument would then collapse and we would be unable to draw conclusion C3b.

What you continue to refuse to examine is the possible failure of premise P4b, and it seems to me that this is the crux of the dispute that you are having with iceaura and myself. So, let's discuss that.

What might it mean for something to "have the ability to do otherwise"?

You and Sarkus hold that the only possible meaning of this phrase is that the thing in question is not a system built from determined interactions - that's premise P4b, explicitly set out above. But if the phrase has another meaning, then P4b is invalid, and your argument against free will collapses.

So, let's consider some examples. Start with a train approaching a switch in the track. It might take the left fork or the right fork in the track. Suppose we observe it takes the left fork. After the event, does the train have the "ability to do otherwise" - to take the right fork instead? The obvious answer would be no, it doesn't. During the event, then, as it goes through the switch? Again, no - by the time it is there it is committed to going one way.

How about before the event? Is it conceivable that the train could ever take the right fork instead of the left? If not, then we might ask why the right-hand track was built in the first place. It seems perfectly reasonable to say that, in the general run of things, the train has the ability to go either left or right, although in any given instance it will end up going one way or the other. Another way to express this idea is that that there is no law of physics that rules out the train taking the left fork rather than the right fork. It is not the deterministic laws of physics that determine, in any given experiment, whether the train goes right or left. The laws of physics are the same every time. What's different at different times are what you'd call the relevant "inputs". In particular, the state of the switch at the relevant time will determine which track the train ends up on.

Would it make a mockery of the language in these circumstances to say that, prior to approaching the switch, the train has the "ability to go left or right"? I don't think so. On the contrary, I think this is a perfectly natural way of describing the situation of the train approaching the switch: "It could go left or right."

If your objection to this is that the convergence of atomic trajectories since the big bang, in the deterministic universe, inevitably leads to the railway switch being in one position or the other when the train arrives, and therefore the train has no "ability to do otherwise", then all you're doing is asserting premise P4b, above. But - and I'll highlight this - that's an just assumption you're making - choosing to use language in a particular way, when another way is equally valid.

Here's how iceaura put the same point when you talked about the "possibility of making the 'opposite' choice":

Not "possibility" from an omniscient view of the entire lifespan of the entire universe (that's not at issue): "Ability" , from current observation of the deciding entity. Degrees of freedom in its action (decision making), which it possesses at the moment.
​

iceaura's point is a bit more forceful than my one about the train. Why? Because he's talking about a human being making a choice using the will, and that's the end-point we need always to keep in mind in this discussion. With this in mind, modify my train example just a bit. Consider the human in charge of setting that railway switch so the train goes left or right.

Relevant questions to consider:
1. Does the human being make a choice as to which way the train goes? Answer: clearly, yes.
2. Does an act of will occur in making the choice? Answer: clearly, yes.
3. Does it mangle the language to say that, before the event, the switch man could choose to set the switch either to the left or to the right? Answer: clearly, no.

So, did the switch guy have the "ability to do otherwise" prior to setting the switch one way or the other, according to his current observation in the deciding moment? Was there more than one "degree of freedom" in the action he could conceivably take at that time? Answer: yes (whether this is clear to you is another matter).

Again, you probably want to object "But the atoms since the big bang made it inevitable that the switch guy would, on that particular occasion, decide to make the train go left rather than right, so there was no 'real' ability to do otherwise, just the illusion of an ability." But that would just be you asserting premise P4b, again, which is an assumption, being your preferred definition of the phrase "ability to do otherwise".

If you insist on keeping P4b, then it follows from the rest of your argument that free will is only possible if the will is a system that is not built on determined interactions. That is, free will is only possible in P3 fails instead of P4b.

Do you agree with this, or do you take issue with it?

 

[James R]

Baldeee:

Going back to respond to some questions and points you raised...

Noone disputes the existence of a process of "free will", or "choice" etc. ....

That's exactly what I've been concluding all along.
Not the non-existence of a process but the non-existence of that process granting us an ability to do otherwise.

What does the word "choice" mean, if not an ability to do otherwise? On the one hand, you're saying that people can make choices, but in the next breath you're saying that these choices that happen are illusory - not "real" choices at all. Which prompts the question: what would a "real" choice look like, then? The only possible answer from you would seem to be that the choice would need to be one that takes place in a non-deterministic setting, such as a supernatural choice or a choice determined by some unspecified indeterminate natural process.

Doesn't it strike you as odd that we all walk around every day, never once making a real choice about anything we do, but all the time thinking that we're doing exactly that?

Of course it is open to you to say that we all suffer from a delusion about the real nature of the universe and ourselves. But the alternative viewpoint is that we can and do make real choices that have real, ongoing effects in the world. We make things happen by choosing this or that. What's delusional about that?

You are simply confusing the process called "free will" with that process being "free".

No. I'm pointing out that your definition of what it means to be free is not the only possible one, and in my opinion is actually an inferior one to the alternative.

Oh, we're far from clear, JamesR.
First question for you, for the sake of clarity: do you accept that in a deterministic universe, as argued, the conclusion is that a person has no "ability to do otherwise"?

No, I don't accept that. See my previous post.

 

[James R]

Just as a train can move one way or another if that is the way the tracks go, it is still on the tracks, and still not free to move off them.

Freedom need not imply a total absence of constraints. There are degrees of freedom, as previously discussed.

The question, for the umpteenth time, is not whether there was a process we call "making a decision" but whether that decision is actually free.

If you can't stick to that, and feel the need to keep confusing the issue with whether the process of making a decision occurs or not, then you're being irrelevant.

You agree that people make choices between alternatives. They make decisions. Are these "real" choices and decisions, or "illusory" choices or decisions?
I would say that, even in your deterministic picture, when a person makes a choice she really makes it. That is, the process of coming to a decision is observable and repeatable. It would appear you agree with this.

That is, you agree that people don't have an "illusion of making a choice". They really do make choices. It's good to put that possible point of contention to bed, then. The discussion then is also about whether the real choices that people actually make are "free" or not. Right?

I see why you think it is irrelevant, but it's good to be aware that there are those who say things like "choice is an illusion". We won't be hearing imprecise statements of that kind from you, I trust.

I am discussing at the right level, James.
From the outset it has been accepted that if you/others simply want to talk about the sensation of freedom that we experience, go ahead, noone is stopping you.
I, Sarkus, and presumably others, are more interested in whether that sensation is more than just the sensation of being free but is actually free.

It's a side question, but I might point out that you face an uphill battle in explaining why anybody has this sensation of being free in the first place. Do you have any thoughts on that? For me, it's easy: we have the sensation of being free because we're free.

It would seem, in a deterministic universe at least, to be just a sensation.

I don't think it seems like "just a sensation" to anyone, yourself included.

I mean, discussions about how many angels can dance on a pin head are all well and good, but it's useful if philosophy can connect with the real world once in a while, don't you think? We should at least try to discuss how things are, not how we imagine they might be.

In the predetermined nature of the deterministic universe, if you throw a black box over a chunk of the interactions and call it "choice" you don't change the nature of the universe, or the fact that everything is predetermined.

You just agreed that it's not just a matter of calling it choice. You agreed that people really make choices. Didn't you? The deterministic nature of these choices is not a point of dispute.

If you also only consider part of the overall system, as Sarkus was at pains to explain to iceaura, you can even get what appears to be an indeterministic system in a deterministic universe.

In exercises of choice made by individual human beings, we're only ever dealing with the only part of the overall universe. But iceaura's issue with Sarkus (and yourself) is not about determinism. It is with your assumption that true freedom can only come from true indeterminism (either supernatural or of an unspecified and possibly imaginary natural kind).

I don't dispute what you say in any other context than when discussing the philosophy of it.

We are discussing the philosophy of it. But it appears you now accept the point that people really make choices, so let's move on.

I can of course only speak for myself, but to answer:
1. Yes
2. Yes
3. Yes
4. "If", yes, but the question is whether he was free to make such a choice other than the one he did at the time he made it.
And that includes all the moments previously when he made similar choices not to stop.

Regarding (4), the question had nothing to do with whether he was free to make the choice. As I said, that question was only about outcomes in a deterministic universe.

 

[James R]

The argument premises that it is, but someone can happily challenge that premise.
Do you want to?

Do I want to challenge the premise (P3, above) that the will is deterministic?

Not at this stage. I don't see the need for that, given that I hold that we can have free will even in a deterministic universe.

QM is non-deterministic, at least in most interpretations, for example.

Only in the sense of random outcomes when the state collapses due to a measurement. I don't see how this would enable free will, as I have discussed previously.

As for others, I am not aware of any but I don't know for sure whether might be or not.

In other words, for now, you can't come up with any candidate non-deterministic processes that might permit free will. Okay.

But note that me not being able to provide examples of non-deterministic (or probabilistic) mechanisms does not mean that I assume that there are none.

No more than my not being able to show you an invisible dragon in my garage means that I assume there isn't one.

Yet in his discussions [iceaura] arrives at indeterministic processes: the ability for the same initial conditions to lead to different outcomes.

Where did he say that? Got a link? Or could this be a misreading of his posts?

He can respond to this himself, of course, so I won't presume to speak for him. My personal assessment, at this point, is that he has only been discussing the matter in the context of determinism.

The supernatural nature of "free" would be a conclusion, not an assumption.

As I have shown above, that is not the case.

There's only so many ways that I, or Sarkus, or anyone else, can explain that to you/him before it becomes obvious that your blockage in this regard is outside our ability to clear.
I think I'm well past that stage with iceaura.

Let's look at this objectively. On one side of this little disagreement, there's iceaura and myself; on the other side there's you and Sarkus. We're all at least moderately intelligent guys, I think you'll agree. It follows that we ought to be able to talk it through until we reach a mutual understanding of the position of other, don't you think?

Wow, the hubris is deafening, JamesR.
Sort us out?
Really?

And the following is not hubris?

There's only so many ways that I, or Sarkus, or anyone else, can explain that to you/him before it becomes obvious that your blockage in this regard is outside our ability to clear.

Hmm... something about glass houses goes here.

For you to even talk about "the universe as a whole" suggests that you believe small pockets of indeterminism can arise within the deterministic universe.
Is this what you believe?

See, this is why I think you're probably reading what you want to see into iceaura's posts, when it isn't there. I have nowhere written anything to suggest I believe there are small pockets of indeterminism in the deterministic universe. And I don't believe iceaura has, either.

Nice handwaving, JamesR.

It's not handwaving to point out that the degrees of freedom that go into any human decision process are far more numerous than the degrees of freedom of a proton or a brick in space. If you try to talk about the human being merely as a collection of X million billion atoms (a vast underestimate) then you lose sight of the individual human making a decision.

Do you understand the difference between an assumption and a conclusion?

Yeah. There's no hubris here. Nothing to see, people. Move along.

Because it doesn't matter to us (practically speaking) that our will is not actually free.

That's a strange thing to say. People fight for freedom. What does that suggest to you, in terms of it mattering?

"Oh, don't worry yourselves, prisoners! Freedom is only an illusion, after all!"

 

[Baldeee]

I'm not responsible for anything you decide to claim is a logical implication of my posts.

I don't just claim it, iceaura, I argue it.
If you disagree, you'll need to rebut it with more than "oh, I didn't say that".
And you are responsible for getting your message across, are you not?
If you think I have misunderstood you, or drawn the wrong conclusion, it is for you to show where the error is, not simply say "you're wrong".
That's the way of discussion, is it not?

And it doesn't mean there are.

Which is why I explain why they are there.

Meanwhile: if you haven't dealt with or even recognized the conclusions that were explicitly set out, the arguments that were made, you haven't actually replied to the post.

I have dealt with those.
And with those that weren't explicitly stated.

As stipulated repeatedly over many pages here, both explicitly and by direct implication, the kind of "indeterminacy" supposedly introduced by quantum and chaos theory is not relevant here. No one - least of all you - has presented any physical loopholes through which human mental behaviors - macroscopic and slow and brief as they are - can escape being physically deterministic. So there is no loss in stipulating to the circumstance, and the entire thread has, throughout.

Sure, that's a reason enough to focus on the deterministic universe, but that is beside the point when it comes to whether the original formulation made the assumption that free will requires the supernatural.

Not "possibility" from an omniscient view of the entire lifespan of the entire universe (that's not at issue): "Ability" , from current observation of the deciding entity. Degrees of freedom in its action (decision making), which it possesses at the moment.

So "ability" as judged by observation and sensation, rather than as judged by the predetermined nature of the deterministic universe.
I get that, and I have no issue with it.
It's what I've been saying you judge "free" by all along.
Every time you try to argue against my position you just reconfirm that this is your stance.

Yes. Quit doing that.

I'm not, but JamesR did.

But you do observe the physical nature of the entity that the universe - not you - has thrown that "black box" (human finite lifespan and knowledge) over.

Yes.
It is as deterministic and thus as predetermined as the rest of the deterministic universe.
We do not sit outside of that, regardless of what we might call a sub-process, or regardless of how we might observe of sense such a process to be indeterministic or otherwise "free".
If you throw a black box over a train on a line, is it suddenly able to move off the tracks?
No, all the black box does is provide room for the appearance of local indeterminism within a deterministic universe by looking only at part of the picture.
But everything still works the same way: deterministically, and thus predetermined.

This nature is not an illusion. It is intersubjectively verifiable, theoretically describable, repeatably demonstrable, scientific fact.

The process is a scientific fact, sure.
Not disputed.
Science has never once conducted an experiment to assess the deterministic nature of its reality other than as judged by our conscious sensation of it, or by looking at the incomplete set of inputs (i.e. only those we are consciously aware of - or in some cases perhaps one of the many we are not subconsciously aware of).

The freedom of will of the universe entire is not the matter at hand. Consider the analogy with the 2nd Law.

More handwaving.
Please offer more than that.
"Oh, because the second Law of Thermodynamics allows localised decreases in entropy, surely the deterministic universe can allow localised pockets of indeterminism!"
Is that your argument?
Is that really what you're suggesting?
If it is then you are not referring to a deterministic universe.
Yet you claim to be.
For a universe to be deterministic, as we're discussing, then every interaction is deterministic.
Your handwaving is summarily dismissed.

 

[arfa brane]

Why it doesn't matter if the universe is deterministic, or not, unless you're a theoretical physicist:

We "have" free will or at least we all believe we do. We do because evolution happened; an evolved species without this important adaptation probably would not keep evolving. Free will is an instinct all animals (maybe even bacteria) have evolved. It just doesn't make sense that life can't make choices.

Suppose one day we find out the universe is deterministic, there is absolutely no freedom to choose any action. What would we do (or, not do) if we found that out? Would that discovery really change anything?

 

[Baldeee]

Part the First...

Thanks for your detailed replies. It seems you're still not quite getting the point, so I'll try again. I'll start at the end and then try to go back to tie up some loose ends.

No, I get the point of what you're trying to argue.
I don't think you get my point, nor do I think you actually fully understand your own point.
But there you go.

Here's how you originally put your premises:

First thing to realise is that none of this is disputed. As far as this goes, it is fine. But notice that the words "free will" don't appear anywhere in the premises or conclusion. And that's what we're supposed to be talking about, right?

If you want to draw the additional conclusion that "there is no free will in a deterministic universe" you need some additional premises.

No, you don't.
The term "do other than it must" is another way of saying "able to do otherwise" - which is the notion of "free" that philosophers debate with regard this topic.
As such the argument is about whether or not "free" exists.
And as such there can be no will that is "free".
Is there the process of "free will" - i.e. the process of "making a choice"?
Yes, that is not disputed.
It is the "free" that is disputed.
The argument sees nothing "free" in a deterministic system.
The argument does not limit itself to a deterministic universe, only to deterministic systems.
Thus there is no assumption that to be "free" is to be supernatural.
If one limits the discussion subsequently to that of a deterministic universe then one is introducing an additional premise that the universe is a deterministic system.
Thus an additional conclusion would be that there is no "free" in the universe, just like concluding that there is no "free" in the will.
I.e. it is still a conclusion, not an assumption.

One possible premise might be:
P0a: Something is not free if it is determined.

Already stated - premise 1.

Then we could conclude:
C2a: The mind and will are determined (follows from P1 to P3).
C3a: The will is not free (follows from P0a and C2).

That would be a bad argument, though, P0a begs the question. We're trying to establish whether there is free will in a deterministic universe. We can't start with the supposed conclusion as an assumption.

First, the original argument did NOT assume that the universe is deterministic.
Thus it is not begging the question with regard the original scope of the argument, for that reason alone.
If you want to limit the scope to the deterministic universe (I have had no issues with that, and find it simpler so as to avoid issues of QM etc), then it is still no more begging the question.
One simply adds another assumption that the universe is itself a deterministic system.
One then concludes that the universe is not free, just the same as any other system that is deterministic.

You therefore suggest the premise:
P0b: Something is free if it has the ability to do otherwise.

This was a given, the "do other than it must" (reworded to the more usual "able to do otherwise") being what philosphers have always taken to be what it means to be "free".
If we can not start from that...?

With this premise, you would presumably like to draw the conclusion:
C2b: The will has no ability to do otherwise.
C3b: The will is not free (follows from C1 and C2).

But you can't get to C2b from premises P1 to P3, since those premises make no mention of any "ability to do otherwise", which is about choice (an "ability") and not (as in P1) about a system doing as it must. You need another premise, or another argument. The additional argument you're now running looks something like this:

P4b: If a system is built from determined interactions, then it has no ability to do otherwise.
C2b: The will has no ability to do otherwise (follows from P4b and P3).
C3b: The will is not free (follows from P0b, C1 and C2b).

You're over complicating things, JamesR, simply because you're not seeing "do other than it must" as "ability to do otherwise".
Those two are synonymous.
If you had read through the thread as you claimed you would have seen me explain this previously.
Post #188: "Free: able to do other than it must" - i.e. "able to do otherwise".

We have previously touched on two ways in which we agree that argument (which includes the added premises P0b and P4b) could fail, both of which occur when P3 turns out to be false, after all. That is, the conclusion that there is no free will would not follow if it turns out that the will is a system built from indeterminate natural interactions, or if the will is a system built on supernatural interactions (also undetermined). We agree that in both cases the argument would then collapse and we would be unable to draw conclusion C3b.

P0b and P4b are not new premises but already within the argument - notably P1 and P2 respectively.
And still no question begging, any more than Socrates being mortal is question-begging through the premise that he is a man.

As for P3 being false, this is possible - IF you aren't talking about a deterministic universe.
If you are then every system within that universe is deterministic, otherwise the universe is not deterministic.
Now you could describe a system that is open, where only certain elements of the system are identified and considered, and that could give the appearance of being an indeterministic system (same initial conditions of those elements yet a different output) but the actual closed system governing that outcome is still deterministic, the outcomes still predetermined, and all you have is the appearance of being able to do otherwise.

What you continue to refuse to examine is the possible failure of premise P4b, and it seems to me that this is the crux of the dispute that you are having with iceaura and myself. So, let's discuss that.

Premise 4b is otherwise referred to as premise 1.
No need to add it in again.
But yes, this is the crux of the issue.
And this is where both I and, more explicitly Sarkus, has been pretty vocal in that if you have a different understanding of the phrase then you can reach different conclusions.
I, for one, have no issue with that at all.
Do you?

What might it mean for something to "have the ability to do otherwise"?

You and Sarkus hold that the only possible meaning of this phrase is that the thing in question is not a system built from determined interactions - that's premise P4b, explicitly set out above. But if the phrase has another meaning, then P4b is invalid, and your argument against free will collapses.

It doesn't collapse, as it remains applicable to that notion of "free" / "ability to do otherwise".
This is what has been stated all along.

So, let's consider some examples. Start with a train approaching a switch in the track. It might take the left fork or the right fork in the track. Suppose we observe it takes the left fork. After the event, does the train have the "ability to do otherwise" - to take the right fork instead? The obvious answer would be no, it doesn't. During the event, then, as it goes through the switch? Again, no - by the time it is there it is committed to going one way.

How about before the event? Is it conceivable that the train could ever take the right fork instead of the left? If not, then we might ask why the right-hand track was built in the first place.

But the right hand fork never was built in the first place.
The only thing that was built was an imagination of the right hand fork.
It was never actually there.
Of course we don't know that it was never there, consciously speaking, but that's what the argument concludes.

It seems perfectly reasonable to say that, in the general run of things, the train has the ability to go either left or right, although in any given instance it will end up going one way or the other. Another way to express this idea is that that there is no law of physics that rules out the train taking the left fork rather than the right fork. It is not the deterministic laws of physics that determine, in any given experiment, whether the train goes right or left.

Um, yes it is - unless we only consider certain elements of the system.
In which case we can get the appearance of indeterminism (same initial set up of those conditions yet different outcomes).
In such instances it is necessarily true that something other than the considered elements was determining the outcome.
And unless you consider all the elements that determine the outcome, you're not considering the actual system behind experiment.
At least not in a deterministic universe.

The laws of physics are the same every time. What's different at different times are what you'd call the relevant "inputs". In particular, the state of the switch at the relevant time will determine which track the train ends up on.

Yes.

Would it make a mockery of the language in these circumstances to say that, prior to approaching the switch, the train has the "ability to go left or right"? I don't think so. On the contrary, I think this is a perfectly natural way of describing the situation of the train approaching the switch: "It could go left or right."

I don't disagree.
From a pragmatic point of view.
But this is a philosophy forum, and if we can't reach conclusions here that make a mockery of our language, where can we?
Language is driven by how things appear.
Philosophy, at least here, goes deeper than that.