Did you happen to observe my recent demonstration, here on the forums, of how predictable people can be?
— wonderer1

No. I'll take a look if you provide a link. I'm skeptical that the level of prediction you are talking about is as rigorous as what would be required to claim strict determinism. I don't doubt that events in the past have effects in the present and future. That's different. — T Clark

I'm not claiming it "is as rigorous as what would be required to claim strict determinism", but it is a piece of evidence that I think makes the most sense on determinism.

Anyway, what I'm referring to can be found on this page starting with my post which is about the tenth one down on that page. (Sorry I don't yet know how to provide a more direct link.)

Perhaps it depends on your preferences. Few long term determinists, that I have observed, fail to recognize the monkeymindedness of retribution. I think humans recognizing their nature is a good thing.

Of course that's fallacious in all sorts of way. Not least, it's an appeal to consequences. — wonderer1

Do you mean that determinists still blame others for their actions erroneously? Assuming it is, I would say that perhaps they can't help doing that, even if there might not be any rational warrant for it.

I don't understand what you are saying in your last sentence.

Morally, I think it's misleading because it is used to justify a willingness not to hold people responsible for their actions. — T Clark

I know what you mean, but such thinking is perhaps lacking in subtlety. Society has little choice but to hold people responsible for their actions, so there is pragmatic, even if not purely rational, warrant for that. To hold people responsible is not necessarily to blame them, though, but would necessarily entail restraining them by whatever means required, in order to stop them committing further crimes, or in the case of lesser infractions, shunning them or shaming them, in the hope of discouraging them and others from committing undesirable acts. The point there of restraint and even punishment, if necessary, would be to act as an example to others, hopefully persuading them not to commit similar socially unacceptable acts. Whatever works.

Do you mean that determinists still blame others for their actions erroneously? Assuming it is, I would say that perhaps they can't help doing that, even if there might not be any rational warrant for it. — Janus

Yes, blaming reactions are naturally ocurring instinctive emotional reactions that have historically been adaptive for our species and are adaptive still. Being emotional reactions, they aren't particularly conducive to us seeing things objectively. They are evolutionarily adaptive because they are strongly motivating to action. So yes, we can't help doing that.

However, understanding the nature of blame reactions allows for nuance and skill in modulating how one behaves in response to a having a blaming state of mind - from philosophising - to unleashing the angry ape.

I don't understand what you are saying in your last sentence. — Janus

What I was trying to convey in saying, "Of course that's fallacious in all sorts of way. Not least, it's an appeal to consequences.", is that I don't expect people to see what I said prior as a rational argument. Just reinforcing that this is a matter of subjective preference on my part.

Nice video! I had heard of those kinds of experiments, but never seen them in action.

What I was trying to convey in saying, "Of course that's fallacious in all sorts of way. Not least, it's an appeal to consequences.", is that I don't expect people to see what I said prior as a rational argument. Just reinforcing that this is a matter of subjective preference on my part. — wonderer1

Right, I think I see what you are saying there now, although I can't see humans recognizing their natures as anything but a good thing, or at least a necessary prelude to good things, and I'm not sure that's merely a personal preference as opposed to an objectively good thing, socially speaking..

Anyway, what I'm referring to can be found on this page starting with my post which is about the tenth one down on that page. — wonderer1

I looked at all your posts on that page and all I saw was you trying to piss off another poster. Is that what you mean by determinism, the ability to predict what will make people angry. That's a pretty weak branch to build your tree house on.

I know what you mean, but such thinking is perhaps lacking in subtlety. Society has little choice but to hold people responsible for their actions, so there is pragmatic, even if not purely rational, warrant for that. To hold people responsible is not necessarily to blame them, though, but would necessarily entail restraining them by whatever means required, in order to stop them committing further crimes, or in the case of lesser infractions, shunning them or shaming them, in the hope of discouraging them and others from committing undesirable acts. The point there of restraint and even punishment, if necessary, would be to act as an example to others, hopefully persuading them not to commit similar socially unacceptable acts. Whatever works. — Janus

As I said previously, I know that people are affected by things that happened in their past, how they were socialized, and what they've learned. I think it makes sense to keep those things in mind when holding people responsible for the consequences of their behavior. I read that one state, I think it was Texas, doesn't allow evidence of childhood neglect or abuse to be presented during murder trials, but they do allow it to be used during the penalty phase when appropriate punishment is determined.

All that being said, I think that's a whole different thing than what I typically call determinism. I don't doubt that the upcoming events can be predicted with a certain level of accuracy. We can predict weather more or less accurately up to about a week ahead. On the other hand, you will hear squawking in my house when it rains when weather reports say it is supposed to be sunny. Even the best predictions tend to be probabilistic rather than definitive.

All that being said, I think that's a whole different thing than what I typically call determinism. — T Clark

Yeah, I know I haven't taken the time to layout the the way I'm using terms, and it's unsurprising that we are talking past each other to some extent. So as some clarification...

1. I consider it quite plausible that the world is indeterministic in light of what I know of physics.

2. I have a lot of history of arguing for 'determinism' in the context of discussing free will. Undoubtedly that is coloring the way I've approached the discussion.

The first paper that you cited makes an important point about predictability right in the abstract, by drawing a distinction between external predictability and embedded predictability: — SophistiCat

The distinction does save the logical coherence of determinism in the short term, but at what price? Does it rise above the level of an ad hoc response to the paradox of predictability? Is the determinist doing more than merely defending their theory by saying, "Oh, well in that case we stipulate that our observer is not part of the universe"?

rightly makes the claim that the demon must be "causally isolated from [our universe]." But is it really coherent to envisage a being who is outside of the causal universe in this manner? And even if it is coherent in general, upon closer inspection we find that in this case the "causal isolation" is odd, and also appears to be ad hoc. After all, knowledge is commonly understood to be causal, and therefore if the demon has knowledge of what occurs in our universe then how could he be causally isolated from it? At this point does the determinist just make another ad hoc distinction and say, "Oh, well the demon is causally isolated except for his knowledge, which is caused by the events which occur in our universe"? The demon begins to look more and more like Dickens' Ebenezer Scrooge, as he traverses time with ghosts, than the sort of thing that philosophers are concerned with.

I tend to think that predictability really is a problem for determinism, and in precisely the way that Rummens and Cuypers set out (i.e. it is a problem in principle, which remains even when the demon is granted unlimited knowledge and computational power). Theism has struggled with a similar problem for thousands of years, but in the reverse direction, where God is causally distinct except for what he causes within the universe. God has an outbox but no inbox; the demon has an inbox but no outbox. Neither thesis is easy to make sense of, but presumably the determinist will be even more bothered with paradox than the theist.

suggests that determinism without in-principle predictability is a meaningless idea. Whether or not that is right, such a form of determinism is a great deal more meaningless and toothless than the sort of determinism which brings along with it the intuitive consequence of in-principle predictability.

The Paradox is roughly this: information or knowledge of the initial conditions and laws of nature should allow a true prediction of the action of some person or subsystem with those initial conditions and that is governed by those laws of nature. Such a prediction must be true. However, if the person or subsystem in question acts in a way that falsifies the prediction, then the prediction is not true. In brief, the prediction must be true, however it is not true when the prediction is falsified by the action of the person or subsystem considered. — NotAristotle

The problem here is that we need to know, with absolute certainty that the conditions have been met, in order for the experiment to be useful. The two conditions are knowledge of the initial conditions, and accurate laws of nature. If it is not known with absolute certainty that these two conditions are met, then failure of the prediction could be the result of inadequate knowledge of the conditions. And, success of the prediction is only useful to the extent covered by Hume's induction problem. Since we cannot know the two conditions with absolute certainty, due to that induction problem, the proposed experiment is useless.

Elaborating on my first post...

It seems to me that a core issue with respect to the "paradox of predictability" is the question of whether the Laplacian demon is himself deterministic. Presumably the determinist would claim that the demon is deterministic, in which case we would have to admit the possibility that there is a third universe where a different demon is "causally isolated" from the first two universes. This demon would be able to predict the behavior of the first demon as well as everything which occurs in the first universe. And then we would need a third demon and a fourth, unto infinity.

Now perhaps this isn't a vicious infinite regress since it isn't causal in nature, but it does help reveal an incoherence in the determinist's claim. For the determinist the demon both accounts for determinism via his predictions, and is accounted for by determinism via his deterministic nature. This contradiction was already present in the human being, who in a similar way both transcends determinism in her ability to conceive and espouse it, and is contained by determinism ex hypothesi. The determinist claims that the human being who herself theorizes determinism is at the same time entirely encapsulated by determinism, and it is in this that the contradiction begins to take life. This is similar to the "Argument from reason."

"Why must the demon be deterministic?" Because the human being has already been claimed to be deterministic, and the demon is only different from the human being in accidental ways. The demon's mind is really just a human mind with additional memory and processing power. The mode of knowledge is exactly the same. If it weren't, then there would be an equivocation between the demon's 'prediction' and what we understand by 'prediction'. The key idea here is that something cannot be simultaneously predicting and predictable, and this is what gives rise to the ad hoc idea of an "embedded system." But to outsource the problem of prediction to an "external system" is no answer at all if the external system suffers from the exact same predicting-predictable problem that the embedded system suffers from. The problem arises not primarily because the system is embedded, but rather because the determinist independently claims that the system is deterministic. The idea that the system is embedded is only a consequence of the claim that the system is deterministic, and if embedded and external systems are both deterministic then such a distinction is surely in vain.

The inference to embeddedness was already problematic from the get-go. Of its very nature, the determinist's claim is not constrained. It is not limited to a subset. It is not merely a claim about "this universe." It is a radically inductive and metaphysical claim that applies to all universes and all minds. The embedded/external distinction is then a failure to understand the radicality of the determinist's claim, as though there could be some non-deterministic vantage point. In theorizing determinism,* the determinist is literally claiming to do something that they purport cannot be done, and when this is pointed out the only recourse is a string of ad hoc responses that kick the problem down the road, inch by inch.


* I submit that there is a sense in which the theorizing of determinism parallels the proving of determinism, or being able to predict everything as the demon does. Just as the hypothesis that the demon is able to predict all events brings with it the notion that the demon is not one of the things predicted, so, in a lesser sense, does the act of theorizing bring with it the notion that the theory does not encompass the theorizer. The absurd result of determinism is that the determinist is simultaneously observer and observed, predictor and predicted, theorizer and theorized, agent and patient.

Issue 1: What do you make of this thought experiment? Does it disprove determinism? — NotAristotle

In my view, no. The thought experiment is not just practically impossible, it is also in principle impossible in all conceivable deterministic universes.

I read your two objections, and I believe you rejected the objections prematurely.

The distinction does save the logical coherence of determinism in the short term, but at what price? Does it rise above the level of an ad hoc response to the paradox of predictability? Is the determinist doing more than merely defending their theory by saying, "Oh, well in that case we stipulate that our observer is not part of the universe"? — Leontiskos

Depends on what sort of determinism is at stake. The definition that I quoted from one of the papers commits only to the existence of a one-to-one mapping between states of the universe at different times. This says nothing about observers and predictability, so determinists do not need ad hoc assumptions to defend against the paradox of predictability, as long as they are willing to concede that some types of predictability are not realizable in principle in a deterministic universe. Though I am not a committed determinist myself, to me that does not seem like a high price to pay. Limited predictability certainly does not go against our experience.

↪andrewk rightly makes the claim that the demon must be "causally isolated from [our universe]." But is it really coherent to envisage a being who is outside of the causal universe in this manner? — Leontiskos

Depends on who you ask. To Laplace the demon is just a thought experiment illustrating the concept. Laplace's determinism commits to causality and computability, so it is a little stronger than the minimal determinism discussed above, but it does not depend on the existence of an omniscient observer. If instead we are talking theology - that's different, but then our starting positions going in are different as well: we are no longer bound by the assumptions of naturalism and causal closure.

↪T Clark suggests that determinism without in-principle predictability is a meaningless idea. Whether or not that is right, such a form of determinism is a great deal more meaningless and toothless than the sort of determinism which brings along with it the intuitive consequence of in-principle predictability. — Leontiskos

@T Clark throws around accusations of meaninglessness rather freely, but that's on him. I rather think that a determinism that is demonstrably incoherent is a lot less meaningful than one that does not suffer from such a defect.

I originally said that the minimal definition of determinism that does not commit to predictability of any sort is the more conventional one. That can be debated, but I would maintain that it is close to what is usually meant by determinism in the sciences, which are concerned with specific laws and theories, rather than final and absolute truths about the world. In such contexts distinguishing deterministic and indeterministic systems is meaningful and useful.


I find that people's idea of "determinism worth having" or determinism to be avoided at all costs is strongly influenced by their underlying worries going into the debate: worries about human freedom, worth and responsibility on one side, and worries about order, predictability and intelligibility on the other side. I think it is worth making explicit your stakes if you are going to argue for a particular demarcation. Why is unrestricted in-principle predictability important to you?

T Clark throws around accusations of meaninglessness rather freely — SophistiCat

Hey! I resemble that remark.

Suppose that we want to program a computer (a machine that is known to be deterministic) that would make a robotic arm to pick out a ball: red or blue. However, there is a catch: we program the machine in such a way that it examines all the states it is in, calculates the determined outcome and then does exactly the opposite. Can this be done? No, as it would require an infinite recurrence. Does it prove that computers are non-determinate? No, just that supertasks of this kind are not possible.

The problem here would seem to be that in order for a machine to be able to calculate what itself is going to do, it has to have enough memory to model it's own memory, which is inherently impossible right?

It's like... in order to have a complete model of my own brain, I have to be able to conceive of pretty much every neuron in my brain, but there's no brain design where this is possible, there's no way for a brain to mentally model all of its own neurons.

Yes, but the main problem is that the machine cannot predict an outcome that depends on that prediction. 'Pick an option opposite to what you would have picked' is unrealizable both for humans and for determinate machines: the output needs to be routed to the input, creating an infinite recursive loop.

Yes I agree with that too. It's an insurmountable recursion looking at it either way. It doesn't do anything to discount determinism in my view.

The Paradox is roughly this: information or knowledge of the initial conditions and laws of nature should allow a true prediction of the action of some person or subsystem with those initial conditions and that is governed by those laws of nature. Such a prediction must be true. However, if the person or subsystem in question acts in a way that falsifies the prediction, then the prediction is not true. In brief, the prediction must be true, however it is not true when the prediction is falsified by the action of the person or subsystem considered. — NotAristotle

Its a paradox because commits the mistake of, "We know everything, yet we do not do not know everything".

What you're doing is taking the observer outside the calculation of the system despite insisting that you have all of the information in the system. You're essentially saying, "We predict up to the moment where the observer learns, 'They will pick blue," then ignore everything after. The learning itself must be then taken into the calculation to see what the person will do next. Essentially every time the person learns what they will do next, that learning itself is a new set of parameters that need to be considered in the prediction.

This simply limits how far ahead one could know what they would do next. Its practically calculating in real time. Meaning that a viable prediction of what a person will do next may only be possible within a very small window. It is neither an argument for or against determinism, just against removing the observer's discovery as part of the "we know everything" calculation itself.

No, as it would require an infinite recurrence. — Jabberwock

'Pick an option opposite to what you would have picked' is unrealizable both for humans and for determinate machines — Jabberwock

I think these are different issues. For a libertarian, the difference between a human and a computer lies precisely in the fact that humans do possess infinite recursion. We can reflect and bend back on our own thought in a way that is not limited. The second quote here isn't as interesting, and I doubt it is even true, though this depends on definitions. A computer could be programmed to switch its output to "output = !output" as a response to an input command. But strictly speaking, counterfactuals do not exist for computers.

I think these are different issues. For a libertarian, the difference between a human and a computer lies precisely in the fact that humans do possess infinite recursion. We can reflect and bend back on our own thought in a way that is not limited. The second quote here isn't as interesting, and I doubt it is even true, though this depends on definitions. A computer could be programmed to switch its output to "output = !output" as a response to an input command. But strictly speaking, counterfactuals do not exist for computers. — Leontiskos

We can modify the description of the experiment to remove the recurrence: the printout is not read by Ned, but by his colleague, Ted. Ted reads that Ned will go for walk and Ned does not. Does it disprove determinism? No, it just assumes libertarianism, there is no paradox at all.

Thanks for your response, . I am enjoying your posts. Thanks too for your ignore extension.

...so determinists do not need ad hoc assumptions to defend against the paradox of predictability, as long as they are willing to concede that some types of predictability are not realizable in principle in a deterministic universe. — SophistiCat

Echoing my elaboration post, what justification is required to claim that a system is deterministic? Exhaustive predictability is the strongest form of justification, is it not? At least when it comes to systems which are not man-made (artificial)? And at the very least, everything in the system must at least plausibly be in-principle predictable. It's not at all clear to me that the thesis of determinism can be separated from a claim of in-principle predictability, and if this is correct then where in-principle predictability is incoherent, determinism fails.

I would want to say that no intellect which understands determinism could be deterministic. If such an intellect claims that it itself is deterministic, then either it does not understand what determinism means (and is therefore equivocating), or else it does understand what determinism means and is drawing a non-sequitur. To understand what determinism means is at the same time to place oneself outside of the deterministic paradigm. As I said in my follow-up, the theorizer can never be accounted for by his theory (at least in the way the determinist supposes he could be).

Though I am not a committed determinist myself... — SophistiCat

Right: earlier you said:

At the same time, I am not convinced that there is one true theory to rule them all at the bottom of creation. Which in turn makes it meaningless to ask whether the world is really deterministic or indeterministic. — SophistiCat

I think it is nonsensical to claim that the one true theory to rule them all, at the bottom of creation, is determinism. Even logically speaking, if determinism were true we would never be able to know and understand that fact. Supposing we had truly understood and encompassed that fact, then our mind would have transcended determinism, in which case it would not be true.

I originally said that the minimal definition of determinism that does not commit to predictability of any sort is the more conventional one. That can be debated, but I would maintain that it is close to what is usually meant by determinism in the sciences, which are concerned with specific laws and theories, rather than final and absolute truths about the world. In such contexts distinguishing deterministic and indeterministic systems is meaningful and useful. — SophistiCat

But determinism is a "final and absolute truth about the world," and even the minimal definition, provided in your very first post, is committed to in-principle predictability. Scientists predicate—and are justified in predicating—determinism of subsystems. This is meaningful and useful. But the philosophical theory of determinism does more: it predicates determinism of the set of all things, including the theorizer. This, I say, is neither meaningful nor useful.

I think it is worth making explicit your stakes if you are going to argue for a particular demarcation. Why is unrestricted in-principle predictability important to you? — SophistiCat

I am an advocate of human freedom, but more than that, I am often led to believe that determinism is just incoherent. Or more precisely, the claim of determinism is incoherent, at best involving an equivocation which invalidates it. My guess is that this rests on my conviction that true knowledge—which is different than Plato's "true opinion"—cannot be necessitated. If we had true knowledge that determinism is true, this would mean that all our knowledge is necessitated, in which case our belief regarding determinism could not be true knowledge at all. It is only coherent to claim that subsystems are deterministic.

(I realize this post involves many redundancies. In my defense, I wanted to try a few different angles because in the past the argument has been difficult to convey.)

Echoing my elaboration post, what justification is required to claim that a system is deterministic? Exhaustive predictability is the strongest form of justification, is it not? At least when it comes to systems which are not man-made (artificial)? And at the very least, everything in the system must at least plausibly be in-principle predictable. It's not at all clear to me that the thesis of determinism can be separated from a claim of in-principle predictability, and if this is correct then where in-principle predictability is incoherent, determinism fails. — Leontiskos

Predictability is the most straightforward and intuitive path towards inductive (or abductive, if you prefer) inference of determinism. But induction (abduction) is not exhaustive by its very nature. On the other hand, if you are looking at a formal model, you may be able conclude whether or not it is deterministic without demonstrating predictability, simply by analyzing its structure.

Quantum mechanics is an instructive case in point. It is often thought of as a paradigmatically indeterministic theory. Indeed, as far as its observable predictions go, it is most definitely indeterministic. And yet, there are competing indeterministic and deterministic interpretations of quantum mechanics, none of which are obviously true or false (or there would not be a competition).

In practice, we are always looking at the world through a veil of epistemic underdetermination: unknown, uncertain and/or uncontrollable factors are always in play to a greater or lesser extent. But our mental models can be either deterministic or indeterministic, as suites the occasion, or as suites your taste, if the choice is not obvious. Those models that work best (or that we like best) we hold as saying something true about the world, however provisionally.

I would want to say that no intellect which understands determinism could be deterministic. If such an intellect claims that it itself is deterministic, then either it does not understand what determinism means (and is therefore equivocating), or else it does understand what determinism means and is drawing a non-sequitur. To understand what determinism means is at the same time to place oneself outside of the deterministic paradigm. As I said in my follow-up, the theorizer can never be accounted for by his theory (at least in the way the determinist supposes he could be). — Leontiskos

Yeah, I didn't get that bit. I don't need to know everything in order to know (or have an opinion about) something. Perhaps it all just comes down to what you said later:

My guess is that this rests on my conviction that true knowledge—which is different than Plato's "true opinion"—cannot be necessitated. — Leontiskos

Well, I don't share that conviction, and neither would any determinist, obviously.

But determinism is a "final and absolute truth about the world," and even the minimal definition, provided in your very first post, is committed to in-principle predictability. — Leontiskos

No, it's really not.

Predictability is the most straightforward and intuitive path towards inductive (or abductive, if you prefer) inference of determinism. But induction (abduction) is not exhaustive by its very nature. — SophistiCat

Certainly it is true that an inductive or abductive approach would not fulfill the canon of exhaustive predictability, but this only means that the strongest form of justification is not available on an inductive (abductive) model. You could think of exhaustive predictability as an unattainable limit if you like.

On the other hand, if you are looking at a formal model, you may be able conclude whether or not it is deterministic without demonstrating predictability, simply by analyzing its structure. — SophistiCat

Yes, but this is the man-made (artificial) case that I excluded. The determinist's claim is not a claim which limits itself to artificial realities. There is no formal model to justify the determinist's claim, which is a claim about all of reality.

Yeah, I didn't get that bit. I don't need to know everything in order to know (or have an opinion about) something. — SophistiCat

Okay, fair enough. Since our approach to the act of understanding may be different, I may be begging the question here. I would want to say that an intellect which understands something transcends that thing through its act of understanding. So if I understand a Roomba vacuum in its entirety then I have, at least in some way, transcended it. I have contained it in a way that it has not contained me. A concrete example of this would be the case where I am able to predict its movements whereas it is not able to predict my movements.

From there I want to say that 1) to assert that something is deterministic is to imply exhaustive (in-principle) comprehension or standing-over or encompassment; 2) to assert that all existing things are deterministic entails asserting that I myself am deterministic; 3) to assert that I am deterministic involves applying (1) to myself; but 4) I cannot pretend to comprehend or stand over or encompass myself, for it is impossible for something to stand over itself or encompass itself. I cannot understand myself in the way I can understand the Roomba, for the act by which I understand myself can never itself be fully understood by myself. (Let me know if this reasoning is too fast or loose. Because I am largely ignorant of your views I may be shooting at the moon.)

The weak premise here is surely (1). Someone will say, "I am not claiming exhaustive comprehension, but only a probabilistic opinion." To be naively concise, my point is not that the act itself is an act of comprehensive understanding, but rather that the supposition or hunch or opinion contains within itself a failure to recognize the boundary of (4). "I have a hunch that I myself am fully explainable in terms of deterministic principles," involves the idea that a theory which came from minds itself fully explains minds. But that can't be. Just as a mind cannot comprehend itself, neither can a theory produced by a mind comprehensively explain minds. Whatever else we want to say determinism is, it is surely also a theory.

So feel free to have a go at (1), but do give me some insight into your own views in the process.

Well, I don't share that conviction, and neither would any determinist, obviously. — SophistiCat

This is a different argument. I don't want to stretch this post too long, but I want to say something about it. Would you be willing to grant that it appears that the act of understanding is neither necessitated nor inevitable? Or does it simply appear to you that an act which is accepted to be necessitated, like two billiard balls colliding, and an act of understanding, like Pythagoras' act of understanding the Pythagorean theorem, equally possess the quality of "necessitated"? It seems that we usually take necessitation to preclude knowledge, e.g., "He's just parroting the definition of the Pythagorean theorem to pass the quiz. He doesn't really understand it." (Although this example doesn't utilize strict causal necessitation, it does utilize instrumental or consequence necessitation, i.e. <It is necessary to recite this theorem in order to pass the quiz, therefore I will recite the theorem>.)

But determinism is a "final and absolute truth about the world,"... — Leontiskos

No, it's really not. — SophistiCat

Going back to the original source:

...I would maintain that it is close to what is usually meant by determinism in the sciences, which are concerned with specific laws and theories, rather than final and absolute truths about the world. — SophistiCat

A scientist who calls an arbitrary system deterministic—such as a Roomba vacuum—is not thereby a determinist. Determinism is a philosophical theory about the entirety of existence, not some subset of it:

Causal determinism is, roughly speaking, the idea that every event is necessitated by antecedent events and conditions together with the laws of nature. — Stanford Encyclopedia of Philosophy | Causal Determinism

If SEP is correct, then what is at stake is "every event," not "some events." In the argument above, then, determinism enters the stage with the antecedent of (2), "Asserting that all existing things are deterministic."

So apparently determinism is an absolute truth about the world and not a limited truth about certain parts of the world. But is it "final"? Above when you were talking about quantum mechanics you spoke of provisional theories. If you are claiming that determinism is provisional and therefore not final, I have no complaint. I would say that the certitude with which a theory is held belongs to the particular theorizer in question, not to the theory, but I don't think any of my arguments stand or fall based on the theorizer's level of certitude.

Sorry for the late response. I've been traveling and otherwise preoccupied.

Yes, but this is the man-made (artificial) case that I excluded. The determinist's claim is not a claim which limits itself to artificial realities. There is no formal model to justify the determinist's claim, which is a claim about all of reality. — Leontiskos

On the contrary, I wouldn't even know how to understand determinism other than in the context of a model (formal or informal, complete or partial). Even if we take your favored criterion of predictability, what would you make predictions from if not from a model? It's models all the way down when we talk about determinism or indeterminism.

Okay, fair enough. Since our approach to the act of understanding may be different, I may be begging the question here. I would want to say that an intellect which understands something transcends that thing through its act of understanding. So if I understand a Roomba vacuum in its entirety then I have, at least in some way, transcended it. I have contained it in a way that it has not contained me. A concrete example of this would be the case where I am able to predict its movements whereas it is not able to predict my movements.

From there I want to say that 1) to assert that something is deterministic is to imply exhaustive (in-principle) comprehension or standing-over or encompassment; 2) to assert that all existing things are deterministic entails asserting that I myself am deterministic; 3) to assert that I am deterministic involves applying (1) to myself; but 4) I cannot pretend to comprehend or stand over or encompass myself, for it is impossible for something to stand over itself or encompass itself.

The weak premise here is surely (1). Someone will say, "I am not claiming exhaustive comprehension, but only a probabilistic opinion." To be naively concise, my point is not that the act itself is an act of comprehensive understanding, but rather that the supposition or hunch or opinion contains within itself a failure to recognize the boundary of (4). "I have a hunch that I myself am fully explainable in terms of deterministic principles," involves the idea that a theory which came from minds itself fully explains minds. But that can't be. Just as a mind cannot comprehend itself, neither can a theory produced by a mind comprehensively explain minds. Whatever else we want to say determinism is, it is surely also a theory.

So feel free to have a go at (1), but do give me some insight into your own views in the process. — Leontiskos

The weak premise here is indeed (1), but not for the reason you give. As I already explained, "exhaustive (in-principle) comprehension" is not how I understand determinism, and I don't think this tracks with the general usage either.

This is a different argument. I don't want to stretch this post too long, but I want to say something about it. Would you be willing to grant that it appears that the act of understanding is neither necessitated nor inevitable? Or does it simply appear to you that an act which is accepted to be necessitated, like two billiard balls colliding, and an act of understanding, like Pythagoras' act of understanding the Pythagorean theorem, equally possess the quality of "necessitated"? It seems that we usually take necessitation to preclude knowledge, e.g., "He's just parroting the definition of the Pythagorean theorem to pass the quiz. He doesn't really understand it." (Although this example doesn't utilize strict causal necessitation, it does utilize instrumental or consequence necessitation, i.e. <It is necessary to recite this theorem in order to pass the quiz, therefore I will recite the theorem>.) — Leontiskos

Would it be preferable to acquire beliefs as a result of a deterministic or a chancy process? I don't have an intuition one way or another, and I wouldn't trust intuitions anyway - I don't think they are informative in this instance. As for the example that you give, it doesn't seem apt: it is more about demonstrating the depth of knowledge or believing things for the right reasons than about causal necessitation.

I suspect that your real concern here is not with necessitation in the sense of causal determination, but with sourcehood: being an autonomous and responsible agent, the true "owner" and originator of thought and action. Whether or not this is compatible with determinism is a matter of philosophical debate best known from the related subject of free will. It is probably best to leave that for another conversation, but I will only say that the contrary position - that the world is indeterministic - may not be of much help to you if what you really care about is sourcehood. This is something that gives incompatibilists the most difficulty.

A scientist who calls an arbitrary system deterministic—such as a Roomba vacuum—is not thereby a determinist. Determinism is a philosophical theory about the entirety of existence, not some subset of it — Leontiskos

So apparently determinism is an absolute truth about the world and not a limited truth about certain parts of the world. — Leontiskos

True, which is why I think that to be a determinist or indeterminist in the above sense you need to hold to a kind of totalizing reductionist view in which there is (in principle) one true theory that describes the world in its totality. That theory can then be either deterministic or indeterministic. If you don't hold to that view, then I don't see what the terms determinism and indeterminism could even mean to you.

Sorry for the late response. I've been traveling and otherwise preoccupied. — SophistiCat

No worries, I don't mind a slower conversation.

On the contrary, I wouldn't even know how to understand determinism other than in the context of a model (formal or informal, complete or partial). Even if we take your favored criterion of predictability, what would you make predictions from if not from a model? It's models all the way down when we talk about determinism or indeterminism. — SophistiCat

Determinism will itself utilize a model, but that is not what we were talking about. You spoke of an independent model which could then be examined to see whether it involves determinism:

On the other hand, if you are looking at a formal model, you may be able conclude whether or not it is deterministic without demonstrating predictability, simply by analyzing its structure. — SophistiCat

As I have granted, we might have an exhaustive formal model for an artificial reality. For example, we might have the schema and the code for a Roomba vacuum, and from this formal model we would be able to decide whether the vacuum is deterministic. But the determinist's claim is a claim about all of reality, and we do not have a formal model for all of reality (because it is not artificial). Because we cannot circumvent prediction without a formal (a priori) model, and there is no formal model for all of reality, therefore we cannot circumvent prediction with regard to determinism (which is concerned with all of reality). The epistemic route to claims of determinism will always, then, depend on prediction.

I suppose someone could draw up an equation that they claim formally models all of reality, but even in the rare case where we take them seriously, the equation will be accepted or rejected based on its predictive capabilities. I don't think there is the possibility of circumventing prediction when it comes to the epistemology of determinism.

The weak premise here is indeed (1), but not for the reason you give. As I already explained, "exhaustive (in-principle) comprehension" is not how I understand determinism, and I don't think this tracks with the general usage either. — SophistiCat

But you haven't provided any alternative to the objection I gave to premise (1), and that objection is based in large part on what you said against "exhaustive (in-principle) comprehension." Namely, you said earlier, "I don't need to know everything in order to know (or have an opinion about) something" ().

Again, "Just as a mind cannot comprehend itself, neither can a theory produced by a mind comprehensively explain minds." Do you deny that determinism is a theory which would comprehensively explain minds?

I suspect that your real concern here is not with necessitation in the sense of causal determination, but with sourcehood: being an autonomous and responsible agent, the true "owner" and originator of thought and action. — SophistiCat

No, that's not it, but that is another perfectly good argument and we can run with it. There is an argument which ties them together such that necessitation undermines "sourcehood." Here is a copy of an argument I gave elsewhere:

(Argument adapted from E. J. Lowe's A Survey of Metaphysics, starting on page 201):

1. Determinism is true
   
   • {Premise}
2. There are some free actions
   
   • {Premise}
3. My typing into the computer is a free action
   
   • {Premise}
4. All causation is event causation
   
   • {From 1}
5. All events have causes
   
   • {From 1}
6. My typing into the computer has an event cause, e¹
   
   • {From 3, 4, 5}
7. e¹ has an event cause, e⁰
   
   • {From 4, 5, 6}
8. e⁰ has an event cause...
   
   • {From 4, 5, 7}
9. e^-50 is an event cause prior to my birth
   
   • {Temporal reduction}
10. e^-50 is outside of my control
    
    • {From 9}
11. If x is outside of my control, and x causes y, then y is outside of my control
12. If y is outside of my control, then I do not cause it freely
13. Contradiction; 1, 2, or 3 must be false

For the purposes of our argument, (3) is outside of my control precisely because it is necessitated by (9), and therefore its source is external to me. The reason I prefer the other argument is because it cuts more directly at determinism by addressing the act of understanding or the act of theorizing, but of course it is also a more complicated argument.

Note that the first argument is based on the idea that the knowing subject transcends the known object; the second argument is based on the idea that the very act of understanding is not necessitated; and this third argument is based on the idea that the necessitation of determinism places all events outside of anyone's control.

but I will only say that the contrary position - that the world is indeterministic - may not be of much help to you — SophistiCat

The contrary position is not indeterminism (randomness), it is agent causation.

True, which is why I think that to be a determinist or indeterminist in the above sense you need to hold to a kind of totalizing reductionist view in which there is (in principle) one true theory that describes the world in its totality. That theory can then be either deterministic or indeterministic. If you don't hold to that view, then I don't see what the terms determinism and indeterminism could even mean to you. — SophistiCat

I agree with this with respect to determinism, but not with respect to indeterminism. I don't believe the two terms have parity in this context. Namely, indeterminism does not universally relate to reductionism in the same way that determinism does. (This holds whether or not you are simply equating indeterminism with randomness.)

SophistiCat, I have to admit some confusion about your position. It is as if you are saying determinism is true and untrue. Is that your view? If it is, maybe we should be discussing the meaning of a proposition being-true instead.

I am an advocate of human freedom — Leontiskos

I agree with Leontiskos. All humans have a free will and belief in that truth is what is at stake in the determinism debate.

Can't we all agree that we can all predict how the Roomba will act? But the Roomba cannot predict how we will act. Why is that? If we are both just physical systems acting in accordance with the principle of causal closure, why is there an asymmetry in predictability? If determinism is true, it seems to me that predictability should be possible with sufficient computational resources.

It may be that there are some limitations on predictability. For example, perhaps the prediction must be kept secret, lest a counterpredictor falsify the prediction. But then why couldn't we just make secret predictions about how another will act? Surely such predictions must come true if determinism is true?

But such predictions cannot reliably come true because determinism is false.