[skissane]

> “the universe is the extension of the self” is precisely the idea we are talking about.

Idealists can take several possible approaches to the issue of how many people/minds exist:

1) Solipsism: only I exist, and everyone else is a figment of my imagination

2) Many minds: only minds ultimately exist, but many distinct minds exist (George Berkeley, John McTaggart)

3) Open individualism: I exist and everyone else exists too, but we are all ultimately the same person, and the idea that we are different people is an illusion (not necessarily an idealist view, but one open to an idealist to adopt; most famous notable proponent is Daniel Kolak; but Kolak in the introduction of his book I Am You extensively quotes the physicists Freeman Dyson and Erwin Schrödinger as expressing the same view)

4) Pan(en)theism: only one mind/person ultimately exists, but we are somehow "sub-minds"/"sub-persons" of that ultimate person. One might call that single ultimate person "God", albeit it is defining the term "God" in a very different way than classical Western theism does. Or, maybe we could call it the "Universe", or borrow Plato's term "the World Soul". (Maybe there is not much difference between (3) and (4), but (4) would view the distinction between different "sub-minds"/"sub-persons" as more "real" than (3) does.)

5) Panpsychism: everything in the universe (even individual atoms) is conscious, and hence has a distinct mind. This in a sense is a variant of (2), but proposes far more minds than Berkeley or McTaggart would ever have admitted. Not all panpsychists are idealists, but you can certainly be an idealist panpsychist

Critics of idealism tend to focus on (1), but in practice (1) has never had any serious proponents. All serious idealists have espoused (2)-(5) (or maybe some other variation I've missed)

See also the philosopher David Chalmers' paper in which he proposes his own taxonomy of idealisms, different from mine: https://philpapers.org/archive/CHAIAT-11.pdf

As an idealist, my starting position is (2), although I have some sympathy for (4).

> And yes you can derive new “physics” with this idea alone.

I don't know exactly what you mean, but I'm not a fan of that kind of talk.

We have to distinguish between physics the natural science, and the philosophical discipline of the philosophy of physics, which is a sub-discipline of the philosophy of science

The idealism debate fundamentally belongs to metaphysics (although contemporary presentations often focus on it through the lens of philosophy of mind instead), but it has obvious consequences for other philosophical disciplines, including epistemology, philosophy of mind, philosophy of science, and indeed philosophy of physics

But while adopting idealism must lead us to a different philosophy of physics, the actual content of physics the natural science is unchanged. Physics the natural science is ultimately just a bunch of mathematical tools for predicting future observations. Those tools, and how you use them, are exactly the same whether you are a materialist, an idealist, a dualist, or none of the above. The only difference is your answer to the philosophical debates about what those tools ultimately are, or what they ultimately mean.

[hnfong]

I'll admit I'm not too prepared to explicitly state what I meant by the line, but I'd personally take a more nuanced approach than "Those tools, and how you use them, are exactly the same whether you are a materialist, an idealist, a dualist, or none of the above".

I'll say that under standard laboratory conditions they should probably be the same most of the time. I hope you'll agree with me that *assuming* there are divergent predictions made by the "mind-first" approaches, they should be studied together with physics. Otherwise physics would become a study of idealized systems, much like insisting on Newtonian maths when the principles of relativity and quantum mechanics were discovered.

[skissane]

> I'll say that under standard laboratory conditions they should probably be the same most of the time. I hope you'll agree with me that assuming there are divergent predictions made by the "mind-first" approaches, they should be studied together with physics.

Can you give me an example of how a "mind-first" approach might give a divergent prediction, as to the outcome of a practically feasible experiment or observation? Maybe some versions of idealism might produce divergent predictions, but I don't believe divergent predictions are necessary to idealism, and many versions of idealism intentionally eschew divergent predictions.

> Otherwise physics would become a study of idealized systems, much like insisting on Newtonian maths when the principles of relativity and quantum mechanics were discovered.

Physics is a system for predicting future observations given past observations. Relativity and QM won because they generated more accurate future predictions than their predecessors.

But what, ultimately, is it that we are observing? Do the theoretical constructs proposed by physics (particles, waves, fields, forces, strings, branes, etc) "really" exist, or are they just abstract conceptual tools for accurate prediction generation? What does "really" even mean in that question? These are all philosophical questions, and idealism is one family of possible answers to (some of those) philosophical questions–but I don't see how that makes any difference to the whole business of generating accurate predictions of future observations–which is all that physics proper actually is, has ever been, or ever will be.

[hnfong]

The reason I refrained from giving specifics is that I'm mostly trying to figure out how everything fits together in (my version of) "mind-first" concepts, so I'll try to illustrate with a grossly simplified example only for the purposes of explaining the general idea, but not as a statement of fact, nor it is intended as a serious scientific hypothesis.

Let's assume a particular universe where only minds really exist (and more than one mind). Let's further assume that the imagination of the mind can shape the physical world, and in a way that the "local" reality is more strongly influenced by the minds in the vicinity.

Let's say A and B are in an isolated room. They are into alternative medicine and strongly believe A can cure B of a disease. Because there only two minds involved, and they both believed it, B is apparently miraculously cured of the disease.

Now, let's change the setting slightly. This time, in addition to A and B, there are also C, D, and E, who are researchers trying to validate A's claims of miraculous healing. C, D, E are scientists who don't believe in such woowoo and are determined to expose A's frauds. A performs the same acts on B. This time, it does not work, because CDE did not believe in it.

---

Now, back to reality. Given how modern science operates and general disbelief that mind can influence reality, you can see that it is not hard to tweak some variants of these "mind-first" approaches to fit the vast majority of modern scientific observations (i.e. there's no magic healing). But the theories can produce divergent predictions (i.e. magic healing can work if you have enough "faith") under conditions where modern science is unwilling to collect evidence.

And I personally think there should be some way to tweak such theories in a way that first and foremost respects the observations and conclusions made by modern science, but also in a way consistent with a large portion of the religious and mystical traditions. (Did you know why Jesus requested people to have faith as a condition for performing healing? Now you have a theory to explain that. [disclaimer: I'm not remotely close to being a Christian])

I understand that some philosophers may feel content arguing whether we've made up all this and it's all in our imaginations (but not claim any predictions beyond accepted modern science), but it seems (to me at least) to defeat the whole purpose of the exercise if we're positing the universe is just a thought of our minds, and not even consider the possibility that we can imagine something other than what we are imagining right now.

Yes it sounds like quackery and the grossly simplified theories has holes in them, but that's why no self respecting person dares seriously bring up these topics (or let you fully into what they're actually trying to steer the topic towards)...

[skissane]

A lot of people connect idealism with psychic powers, and some even view that as counterargument against idealism. The basic idea seems to be this: (1) I have full control over the contents of my own mind, but very limited control over external reality; (2) but, if idealism is true, then external reality is part of my own mind, so I have full control over it too; (3) therefore, psychic/miraculous powers exist; (4) but, (3) is clearly false, therefore idealism must be false. People who want to believe in the psychic/paranormal/miraculous/etc stop the argument at (3), people who don't and are looking to use this as an anti-idealist argument go on to (4).

But, I think (1) is false. We actually have far less control over the contents of our own minds than many of us think we do. Anyone who has ever struggled with mental illness or addiction knows this fact very well. But, even for people who are thankfully unaffected by either: how much of our choices are truly "free", and how much are they predetermined by our genetics and by social/cultural influences? We don't know for sure, but probably a lot more than many people assume. And if (1) is false, the whole argument falls apart.

A lot of what you are saying seems to be rather adjacent to this line of argument. I don't agree that idealism makes the psychic/miraculous "more likely". I agree they are possible under idealism – but they are possible under materialism too. It may so happen that the laws of this universe, insofar as we know them, don't permit psychic powers or miracles – but, that's a consequence of what those laws happen to be, not of materialism in itself, and materialism could be just as true even with very different laws of physics which did permit psychic powers and miracles and magic and so forth.

Furthermore, the known laws of physics actually do permit all those things, with unimaginably low (but non-zero) probability – quantum tunnelling, quantum fluctuations, thermal fluctuations, etc, permit just about anything imaginable to happen (or at least appear to happen, in a way which nobody could distinguish from them actually happening), with unimaginably small yet still non-zero (and non-infinitesimal) probability. But, in a spatiotemporally infinite universe, any event with non-zero probability (however remote) will almost surely eventually happen, somewhere and somewhen, even an infinite number of times; indeed, in a spatially infinite universe, every non-zero probability event is almost surely happening somewhere right now, even an infinite number of times simultaneously – including your scenario. And people call idealism crazy–is materialism really any better? At least idealists can say "we have no reason to believe the universe actually exists beyond its observable limits", thereby avoiding the threat of a spatially infinite universe in which every possible event almost surely is happening somewhere right now – that way of avoiding the threat comes naturally to (some versions of) idealism, it is much more arbitrary for a materialist.

[hnfong]

Interesting you bring probability up. Nobody knows where these probabilities come from -- we know how to calculate it and make predictions for sure, but we don't know where they fundamentally come from.

That said, even though you say materialism permits pretty much anything, the probabilities are supposed to be radically different. Materialism predicts that "Jesus" is practically impossible, and some versions of idealism suggests it is a dime a dozen. It seems reality is probably somewhere in between.

My personal theory is that the universe pretends as if it is materialistic by fudging with probabilities. (and also with limits of computations in the sense that if you can't practically solve a computation problem the answer may not actually exist in the same sense as observable limits you mentioned)

[skissane]

> Materialism predicts that "Jesus" is practically impossible,

That's not a prediction of materialism itself, that's a prediction of materialism combined with natural science as we know it. In some parallel universe (a popular speculation among contemporary physicists), for all we know, the laws of physics might have been sufficiently different to make "Jesus" "practically possible". Such a universe would have rather different laws of physics to those we observe here, but if materialism is right about the nature of this universe, it would be just as right about the nature of that one too.

And, I'm not sure if "Jesus is practically impossible" is even a prediction of natural science as we know it. I mean, of course, the odds of "Jesus" happening here-and-now by science alone are hyper-astronomically low–something I doubt any Christian would deny; but just make the universe/multiverse big enough, and the odds that "Jesus" happens sometime, some place, even right now, becomes arbitrarily close to 1. "Jesus" is happening "right now" some light years away (within a googolplex or so). If many worlds is true, there are many branches of the wave function in which "Jesus" really happened, about 2000 years ago, in the ancient Roman province of Judea, even if we have to say they are vastly outnumbered by those in which it didn't but people falsely believed it did. Given materialism, and certain assumptions about parallel universes, the central claims of Christianity actually are true, somewhere, even if not here. And, that's not true of Christianity, but of every other religion too. It isn't "impossible", given those assumptions it is almost certainly true; and it isn't clear what work "practically" is doing. Claims about what happened 2000 years ago aren't "practically" anything, and what difference does it make whether it really happened in this universe or in another one?

> and some versions of idealism suggests it is a dime a dozen.

Whether "Jesus" is impossible (just "practically" or even absolutely), or "a dime a dozen"–isn't in my view anything to do with materialism or idealism in itself. There are idealisms in which "Jesus" is impossible, and there are materialisms in which "Jesus" happens, even an infinite number of times, even an infinite number of times right now (and every other moment too).

That said, most idealisms don't really have anything to say about this issue either way.

[tsimionescu]

1, solipsism, has the advantage that there is a solid argument to be made for it - I only have direct access to my own mind. That is why I am calling it coherent.

The other flavors don't have this advantage at all. It is impossible to trust my senses to arrive at the conclusion that other minds exist without first trusting them that they are correlated with features of a non-mind physical world. So, you can't use sense-based observations to claim that the world is made up of many minds.

Even in something like Hinduism, which could be called a form of idealism at a large stretch, the physical world exists as a shared mirage that our minds are made to experience, maya, but the true world is still a single thing, Brahman. And their claim is that this can be directly experienced by you through self reflection - so if we call it idealism, it's still a form of solipsism ultimately, albeit more interesting than I would normally give this credit for.

[skissane]

> 1, solipsism, has the advantage that there is a solid argument to be made for it - I only have direct access to my own mind. That is why I am calling it coherent.

In saying that, you are assuming certain standards for judging whether an argument is "solid". How do you justify those standards? Many would answer that they are axiomatic. But, if our standards for judging arguments are ultimately axiomatic, why can't the existence of other minds be axiomatic too?

By Münchhausen's trilemma, all arguments are ultimately reducible either to circularity, infinite regress, or dogma. Choose your poison, but I think dogma is least the poisonous of the three. I suppose that's another one of my axioms.

Of course, argument by axiom is sometimes very non-convincing – it can be used to defend any position whatsoever. However, most would agree that there is a big difference between defending as an axiom "1+1=2", versus papal infallibility, or the uncreatedness of the Quran, or whatever. The question is, is the axiom "other minds exist" more like the former kind of axiom or more like the latter? Surely, more like the former.

> The other flavors don't have this advantage at all. It is impossible to trust my senses to arrive at the conclusion that other minds exist without first trusting them that they are correlated with features of a non-mind physical world. So, you can't use sense-based observations to claim that the world is made up of many minds.

You can't use sense-based observations to make metaphysical claims–and materialism is just as much a metaphysical claim as idealism or dualism are. There is no possible experiment or observation that could distinguish materialism from idealism, and any possible sense data is equally explainable under other theory.

> And their claim is that this can be directly experienced by you through self reflection - so if we call it idealism, it's still a form of solipsism ultimately, albeit more interesting than I would normally give this credit for.

That Hindu position is arguably closer to my options (3) (open individualism) or (4) (pan(en)theism) than to classical solipsism (my option 1).

In classical solipsism, my mind is truly real, but yours isn't. In the Upanishads, both our minds are equally real (as Brahman), and equally unreal (as maya and karma); in their equal reality they are identical to each other, in their equal unreality they are distinct