I'd agree that idealism doesn't necessarily entail solipsism, but I don't know if I've ever seen any good reasons why it doesn't in any particuar case.

It seems like the best case for idealism that's not solipsism might simply be to partition off the stuff that realists consider mental phenomena--one's own thoughts, desires, etc., from the stuff that realists consider objective stuff--trees, rocks, other people as they appear, etc. and for the idealist to call the former "my mental phenomena" and the latter "mental phenomena that's not mine." The problem, however, arises with why the idealist would consider trees, rocks, etc. mental phenomena that's not theirs. I don't think I've ever seen a good reason for that, and I can't really manage to invent one that doesn't seem ridiculous/like the rationalizations of an isane person. Maybe someone who is an idealist and who isn't a solipsist could explain it.

Even while they had a lot wrong, like the fact that the earth orbits the sun and not the other way around, the "objectivity" of their knowledge (what they could reliably predict) was never founded on the basis of "objective fundamental truth", it was founded on "reliable truth". — VagabondSpectre

I would not say that this ability to predict was founded on a reliable truth at all, it was founded on a falsity. If ancient astrologists, cosmologists, and geometricians mapped the sun, and other planets as circling the earth, and were capable of producing predictions based on these geometrical constructs, then these predictions were derived from a fundamental falsity, not a truth.

I would not say that this ability to predict was founded on a reliable truth at all, it was founded on a falsity. If ancient astrologists, cosmologists, and geometricians mapped the sun, and other planets as circling the earth, and were capable of producing predictions based on these geometrical constructs, then these predictions were derived from a fundamental falsity, not a truth. — Metaphysician Undercover

Well they had to bend their false models to comply with observations in order to be able to make reliable predictions, but you're missing the point.

The predictions that they made were not based in essence on their false models, but instead were based on identifiable patterns in observed phenomenon. For instance, they will have noticed that the sun appears in the sky every day with cyclical regularity. They will have taken this observed pattern and done two things with it: 1, they would be able to make future predictions based on the previously observed pattern, and 2, (If they believed the sun orbited the earth) would have guessed that the day and night cycle is created by how long it takes the sun to complete one orbit around the earth.

While conclusion #2 represents falsehood, conclusion #1 is a completely rational strong cumulative argument (induction) whose strength is can be found in the reliability of the pattern that it observes and hence the predictions that it makes. "Ability to (successfully) predict" IS "reliability". The actual core foundations of their predictions were sound observations, not falsehoods. Their predictions did not work because of sheer luck, they worked because the phenomenon they observed, measured, and then predicted was reliable. Sure it was not "science" in that they were plunging the depths of the physical world in search of root causation, but as it happens their arguments, particularly about what the sun would appear to do in the sky, are in the same magnitude and order of reliability (reliability is science's version of certainty) as much of the best science that we have today.

Many people say science works because of the process of falsification, and they're right. What rigorous attempts at falsification achieves the weeding out false positions, so that the batch of ideas we're left with, while not necessarily "certain", are distinctly more reliable than whatever came before. We care so much about the repeatability of our experiements/predictions because that's what makes them safe; what makes them reliable.

The predictions that they made were not based in essence on their false models, but instead were based on identifiable patterns in observed phenomenon. — VagabondSpectre

The patterns would have been of their own creation, how they interpreted what they saw. So they would have made geometrical figures, patterns, to represent what they experienced (saw). Since the interpretations of what they saw were inaccurate, so were the patterns they created. Why not call these geometrical figures, these patterns, false representations?

The point being, that you can make adequate predictions while maintaining false representations. One could claim that a dragon takes the earth in its mouth every evening, and brings it around, through the underground, spitting it out in the morning, and still predict that the sun will rise. You seem to be questioning whether these representations are actually false. I would say that they are false. How then, does the ability to predict come about if the representations are false?

While conclusion #2 represents falsehood, conclusion #1 is a completely rational strong cumulative argument (induction) whose strength is can be found in the reliability of the pattern that it observes and hence the predictions that it makes. "Ability to (successfully) predict" IS "reliability". The actual core foundations of their predictions were sound observations, not falsehoods. — VagabondSpectre

The problem with #1 is that it refers to patterns. The patterns which are created by the observers, is where the falsehood lies. So it cannot be the patterns which gives the ability to predict, it must be something else. I would say that it is in the numbers. Suppose the ancient people marked an observation point, then they marked the point where the sun would rise each day, from that observation
point. By numbering the days they could have the capacity to predict how many days until the sun rises at a certain point. I suggest that the creation of patterns comes following this ability to predict using numbers, as speculation into why the numbers work for prediction. The patterns are theories then, theories as to why the numbers work for prediction.

"Reliability" is produced by accuracy in the numbering system. This is where you find the value of inductive reasoning, in its relationship to numbering. We can entirely remove the pattern, and rely solely on the numbers. It has always been (infinite number of days), in the past, that the sun rises the next day, so we conclude that it will continue. We need not speculate about patterns to produce this conclusion.

Many people say science works because of the process of falsification, and they're right. What rigorous attempts at falsification achieves the weeding out false positions, so that the batch of ideas we're left with, while not necessarily "certain", are distinctly more reliable than whatever came before. We care so much about the repeatability of our experiements/predictions because that's what makes them safe; what makes them reliable. — VagabondSpectre

I would say that falsification comes about in different ways. First there is falsification with respect to the numbers themselves. Suppose the people found 365 days between when the sun came up at the same place. That's not quite right, so after a number of years, 365 days would be falsified, and they would have to adjust. Secondly, falsification also comes about in respect to the relationship between the geometrical patterns, and the numbers. That there are not precisely 365 days in a year indicates something. It indicates that the year and the day are not parts of the same phenomenon. There is incompatibility, inconsistency between the year and the day, because we cannot make a representation of a year, in which a day remains incomplete. Therefore we must have two distinct geometrical representations, one which represents the day, and one which represents the year. There is a much more evident incompatibility between the month (moon cycle) and the year.

That they refer to the same thing is not that they mean the same thing. And that "intelligent species" refers only to humans doesn't mean that there are no humans. So to say that idealism redefines awareness as reality or that if "reality" refers to awareness then there is no awareness is simply false. — Michael

Then you need to define the word "meaning". You also need to define "reality", "awareness" and "I" in such a way that they refer to the same thing but don't mean the same thing, and then you may begin to convince me.

You can't go from "only mental phenomena exists" to "only my mental phenomena exists". It simply doesn't follow. — Michael

Well maybe that's because I'm thinking of the word "my" in the way a realist does. You need to define "my" if it means something different to you or I will never understand.

Sure, but non-solipsist idealists will argue that there are good reasons to believe that other minds exist but not non-mental things. As above, the non-existence of non-mental things does not entail the non-existence of other minds, and so such reasons are not necessarily ruled out.

Again, that's simply false. "I question the existence of non-mental things" doesn't mean "only my mind exists", and neither does the latter follow from the former. — Michael

How can any idealist argue for the existence of something that they have never experienced? You have never experienced other minds, only other bodies. You infer the existence of other minds by the behavior of other bodies, just as we infer the existence of atoms through the behavior of matter. What you are saying is that you are sure that something you never experience exists, yet the things you experience don't exist when you don't experience them. You are being contradictory.

You also can't go from "only mind exists" to "only minds exist".

Then you need to define the word "meaning". You also need to define "reality", "awareness" and "I" in such a way that they refer to the same thing but don't mean the same thing, and then you may begin to convince me. — Harry Hindu

Reality is everything that exists. Awareness is thoughts and memories and sensations. Exactly as it is for the realist. It's just that whereas the realist would say that both awareness and non-awareness things exist, and so that "reality" refers to awareness and non-awareness things, the idealist would say that only awareness exists, and so that "reality" refers only to awareness.

Again compare with "intelligent species" and humanity. That the former refers only to the latter is not that they mean the same thing or that humanity doesn't exist.

Well maybe that's because I'm thinking of the word "my" in the way a realist does. You need to define "my" if it means something different to you or I will never understand.

It means what the realist means. I don't understand what's hard to understand. You can't go from "only bodies exist" to "only my body exists" and so you can't go from "only mental phenomena exists" to "only my mental phenomena exists".

How can any idealist argue for the existence of something that they have never experienced? You have never experienced other minds, only other bodies. You infer the existence of other minds by the behavior of other bodies, just as we infer the existence of atoms through the behavior of matter. What you are saying is that you are sure that something you never experience exists, yet the things you experience don't exist when you don't experience them. You are being contradictory.

Except the claim isn't "the things I experience don't exist when I don't experience them". It's "things don't exist when they're not being experienced". It doesn't matter if I experience them, only that they are experienced.

The only idealism you're even considering is a solipsistic kind. But not all idealisms are solipsistic.

While conclusion #2 represents falsehood, conclusion #1 is a completely rational strong cumulative argument (induction) whose strength is can be found in the reliability of the pattern that it observes and hence the predictions that it makes. "Ability to (successfully) predict" IS "reliability". The actual core foundations of their predictions were sound observations, not falsehoods. Their predictions did not work because of sheer luck, they worked because the phenomenon they observed, measured, and then predicted was reliable. Sure it was not "science" in that they were plunging the depths of the physical world in search of root causation, but as it happens their arguments, particularly about what the sun would appear to do in the sky, are in the same magnitude and order of reliability (reliability is science's version of certainty) as much of the best science that we have today. — VagabondSpectre

I think you might be missing something here. #2 is the conjectured *explanation* of #1. The reason that certain regularities exist is that the sun orbits the earth, and you cannot, via any logical process arrive at #2 via #1.

Now, when your table of regularities exists, you have an extremely useful tool - you have a "rule of thumb", which may prove invaluable for planting crops etc, but what you don't have is any science.

Science begins when an explanation of certain phenomena, be they regularities or irregularities, is proposed. Why does the sun orbit the earth? Why do we have seasons? Why can't Demeter and Zeus just get along?

Except the claim isn't "the things I experience don't exist when I don't experience them". It's "things don't exist when they're not being experienced". It doesn't matter if I experience them, only that they are experienced. — Michael

How do folks figure that they're experiencing other persons' experiences? (Whatever other folks are when they're just experiences)

Who says they are?

So they'd agree with "things I experience don't exist for me when I don't experience them"?

So they'd agree with "things I experience don't exist for me when I don't experience them"? — Terrapin Station

I don't understand how that follows. Like Harry you seem to be understanding idealism as the claim "X exists only if I experience X". But that's not necessarily the claim. The claim might just be "X exists only if X is experienced by someone". So other minds can exist even if I don't experience them because they are nonetheless experienced by someone (namely, themselves).

And I don't quite understand what you mean by "exists for me". Does that mean something different to "exists"? If not then surely "X doesn't exist for me" doesn't entail "X doesn't exist", and so even if one were to accept "other minds don't exist for me" one need not accept "other minds don't exist".

I don't understand how that follows. — Michael

I didn't say it follows. I asked you a question. Would idealists then say "Things I experience don't exist FOR ME when I don't experience them"? So yes or no, would they say that? There's not a correct answer. I'm just asking a question.

"For me"--"from my perspective" is one way to read it, or "insofar as I know" would be another (and "know" could be read a la acquaintance or propositional knowledge). These different readings might produce differenf answers.

"For me"--from my perspective is one way to read it, or "insofar as I know" would be another. — Terrapin Station

So you want to know if idealists would accept the truth of "the things I experience don't exist insofar as I know when I don't experience them"? Which is to accept the truth of "insofar as I know, the things I experience don't exist when I don't experience them". Which is to accept the truth of "the things I experience don't exist when I don't experience them".

Well, the solipsistic idealist would accept such a claim, but the non-solipsistic idealist wouldn't.

So some non-solipsistic idealists believe that things (can) exist insofar as they know they don't experience them.

How would they know this?

So some non-solipsistic idealists believe that things exist insofar as they know they don't experience them.

How would they know this? — Terrapin Station

They might infer it, just as the physicalist does. But unlike the physicalist they reject the claim that these things are non-mental in nature, either because such a thing is incoherent or because there's insufficient evidence.

I want to get into details though. Infer it how? Based on what?

I want to get into details though. Infer it how? Based on what? — Terrapin Station

That's a separate issue to the topic that I'm discussing, which is that idealism doesn't entail solipsism and doesn't 'define subjectivity out of existence'.

That's a separate issue to the topic that I'm discussing, — Michael

it's not separate to what I'm discussing at the moment, though. It's what I'm interested in. And it has to do with idealism entailing solipsism. To demonstrate that, you need to play along, or you'll never understand it.

And it has to do with idealism entailing solipsism. — Terrapin Station

But it doesn't. It's a straightforward semantic fact that "only mental phenomena exists" doesn't entail "only my mental phenomena exists", just as "only physical bodies exist" doesn't entail "only my physical body exists". If you want to argue that it does then show me that it does. You don't need my participation for that. You can provide the premises and the derivations all on your own.

If you want to argue that it does then show me that it does. — Michael

I just wrote "To demonstrate that, you need to play along, or you'll never understand it."

I'm not saying that in idealists' views this is the case, by the way. What I'm saying is that solipsism is logically entailed by it, and idealists are believing something incoherent if they're not solipsists.

So, we can move past the meta discussion and get into details: Infer it how? Based on what?

I'm not saying that in idealists' views this is the case, by the way. What I'm saying is that solipsism is logically entailed by it, and idealists are believing something incoherent if they're not solipsists — Terrapin Station

But it isn't. How can you derive "only my mental phenomena exists" from "only mental phenomena exists"? You can't. Just as you can't derive "only my physical body exists" from "only physical bodies exist".

In other words, you won't play along. Not surprising.

In other words, you won't play along. Not surprising. — Terrapin Station

Neither is your inability to explain how one can derive "only my mental phenomena exists" from "only mental phenomena exists".

I can't explain it to you so that you'll understand it unless you play along. Why are you against playing along? is there some moral objection to it or something? Do you feel uncomfortable with it for some reason?

I can't explain it to you so that you'll understand it unless you play along. — Terrapin Station

You should be able to. If one thing is logically entailed by another then you should simply be able to list the premises and derivations that show this. That's the beauty of logic.

So here's the starting premise: "only mental phenomena exists". Here's the conclusion: "only my mental phenomena exists". What are the additional premises that would make this a valid argument – and why must these premises be accepted by the idealist who asserts the initial premise?

And the reason that you won't just play along is?

Because I don't need to. If one statement logically follows from another then you can show this without my help. I'm not doing your work for you. You're the one claiming that idealism entails solipsism, so the burden is on you to show why this is the case. Unless you do I can simply dismiss your unjustified assertion.

So you won't play along a la a Socratic dialogue because it's "doing my work for me" in your view.

What if it turned out that you really would only be able to understand this via going through a Socratic dialogue though? You simply think that's impossible?

What if it turned out that you really would only be able to understand this via going through a Socratic dialogue though? You simply think that's impossible? — Terrapin Station

Yes I do. Given that one statement only follows from another if they mean the same thing (or if the latter contains the former), and given that "only mental phenomena exists" and "only my mental phenomena exists" do not mean the same thing (and nor does the latter contain the former) it then follows that "only my mental phenomena exists" does not follow from "only mental phenomena exists".

No Socratic dialogue can undermine straightforward logic.

Right. That sort of overconfidence in your abilities is just the problem though. There's no way to break through that via what's usually done on message boards.