One says that things are physical, the other that things are mental. It's a disagreement on the nature of the fundamental substance. It's not a disagreement on whether or not there are parts of the world that are not me. That would be solipsism vs non-solipsism.

All I'm saying is that idealism doesn't entail solipsism. There can be mental phenomena that isn't me. The Cartesian dualist says as much. — Michael

That isn't all you are saying. You philosophers don't seem to realize the implications of what you are saying. There is always more to what you are saying. It's just that you don't tend to think about the implications of what you are saying on the rest of your beliefs and world-view.

What you are saying is that mental stuff behaves the same way as physical stuff. What you are saying is that science can, and does, explain the behavior of mental stuff. So much for those idealist claims that science can NEVER explain the mind!

What you are saying is that mental light can be bent when passing through a mental glass of water, just as physical light can be bent when passing through a physical glass of water. Again, what is the difference between idealism and materialism, as you seem to imply that the only difference is the name of the substance? Why do we need a body if everything is mental?

There's no reason to believe that the existence of physical bodies is required to maintain this separation of minds. — Michael

Something is required to explain the separation of minds. Are mental bodies required to maintain the separation of minds? How are mental bodies different than physical bodies?

Pretty much. As Hempel's dilemma shows, there's hardly even a coherent understanding of what it even means be a physical thing. And I think the same dilemma can be used to question the notion of the mental, too (and any other monism).

Substance is a vacuous concept. — Michael

Then idealism/materialism (or any idea that says that there is substance) is an idea that is based on a vacuous concept?

I voted idealism because I think it's the best solution to the mind-body problem. Also it's a super sexy position. The metaphysical weak are those who depend on an unchanging reality to cope with the flux of existence. — darthbarracuda

What do you mean it's "the best solution" to the mind-body problem? And what does that have to do with the becoming/being dichotomy (flux)?

Something is required to explain the separation of minds. — Harry Hindu

Why? Do we require something to explain the separation of physical stuff? What separates this photon from that electron?

Then idealism/materialism (or any idea that says that there is substance) is an idea that is based on a vacuous concept? — Harry Hindu

Yes. Hempel's dilemma.

If you're a physicalist and believe that the mind is just brain processes (for example), do you understand idealism to be the claim that only brain processes exist? Or do you understand the claim "only mental phenomena exist" to be something else?

It might be worth actually looking into pluralistic idealism.

It's really quite simple. One can claim that only mental phenomena exists without claiming that only my mental phenomena exists, just as one can claim that only physical bodies exist without claiming that only my physical body exists.

I would say that, for an idealist, an event is imaginary if it was invented and narrated by somebody that had no good reason to suppose that it ever happened.

A materialist can use the same definition. — andrewk

Yes, but the difference all hinges on what the idealist means by saying that an event did or did not happen. So, it is misleading to say the materialist uses "the same definition", because when the realist or the materialist says something happened they usually mean that its happening does not depend on anyone's experiencing it happening (unless of course it was an experiential kind of event).

I am under the impression that realists interpret imagined counterfactual possibilities of perception as being *evidence for* the existence of mind independent objects.

Conversely i understand idealists as interpreting imagined counterfactual possibilities of perception as being *the definition of* "mind-independent" objects. — sime

Sure, and in that case both are acknowledging the existence of "mind independent objects". The materialist says they are independently materially existent, and an idealist (who acknowledges the existence of human mind-independent objects) says they are independently ideally existent. The latter position, to be coherent, must posit God or some kind of universal or collective mind. That is just the point I have been making.

In a sense, there's a lot more to the story of imaginary and real. E.g. are you’re perceptions, emotions, etc. imaginary or real? — javra

I can't see the "lot more", I think it is fairly simple: if I imagine something, my imagining it is real, but what is imagined may be merely imaginary, obviously.

If I experience an emotion, the emotion is real, and so is the experiencing of it. If I perceive something the perception of it is real, and so is the perceived object, at least in cases where the perception is veridical.

I can't see the "lot more", I think it is fairly simple: if I imagine something, my imagining it is real, but what is imagined may be merely imaginary, obviously.

If I experience an emotion, the emotion is real, and so is the experiencing of it. If I perceive something the perception of it is real, and so is the perceived object, at least in cases where the perception is veridical. — Janus

Given the context in which my reply to you was made:

The materialist affirms that only matter is real. The epiphenomenalist affirms likewise. Sort of self-contradictory reasoning given that this affirmation is made via means devoid of matter: e.g., thoughts, percepts, and that skeleton-in-the-closet sometimes termed one’s choice, or will, or intention (such as regarding what is in fact real).

If you would like to clarify you’re stance, what justifications do you utilize to determine which mental givens are real and which mental givens are imaginary? As a reminder, your real thoughts (as opposed to those either imagined (maybe hallucinated?) or fibbed about) are not empirical in the modern sense of the term empirical. Neither are your emotions, sensations, intentions, etc. They don’t stand outside you as something you can perceive via the physiological senses. (same could be somewhat also said of cultures, as an added example)

BTW, for the sake of philosophical rigor and verity—since this is a philosophical forum—idealists such as Plato were/are realists … only not materialist-realists.

Sort of self-contradictory reasoning given that this affirmation is made via means devoid of matter: e.g., thoughts, percepts, and that skeleton-in-the-closet sometimes termed one’s choice, or will, or intention (such as regarding what is in fact real). — javra

I think you are taking for granted what you need to demonstrate: that reasoning is "made via means devoid of matter".

In any case I am not arguing for materialism; so I think you have misunderstood "my stance". All I'm concerned with is unpacking what is logically involved in the various stances.

And for the sake of "philosophical rigor and clarity", any idealist who claims that the ultimate reality is ideal, not material, is obviously a realist about that claim, since they are saying that this is the case independently of what any human mind experiences or thinks about it. My whole point has been that the positing of a universal mind, God or "realm" of ideas is necessary to make this form of idealism coherent. I also want to say that I cannot see how any other form of idealism could be coherent. since it would fail to explain how a shared world is possible.

I agree. In fact, like this one, nearly all sentences that anybody ever utters are as meaningful to idealists as to materialists. It is only when one drills down through a long sequence of definitions from the sentence that one can start to discern any difference. That's why the simple, snappy 'refutations' of idealism like Johnson's kicking a stone or asking about fictional characters are so ineffectual.

I think you are taking for granted what you need to demonstrate: that reasoning is "made via means devoid of matter". — Janus

And I, in turn, think you are applying an all or nothing perspective to idealism that doesn’t need to be—and almost always isn’t when looking at actual idealists, be it Plato, Pierce, or others. We look at a particular concrete object over there to understand if it’s actually made up of matter or mind … and then it seems the next question is always “whose?”— but this is misplaced. The materialism/idealism debate is not one of physics. It is one of metaphysics.

I’ll try to justify “that which I need to demonstrate” more, however, only if you are polite enough to first try justify that which I previously asked you to justify regarding what is real.

We look at a particular concrete object over there to understand if it’s actually made up of matter or mind … and then it seems the next question is always “whose?”— but this is misplaced. The materialism/idealism debate is not one of physics. It is one of metaphysics.

I’ll try to justify “that which I need to demonstrate” more, however, only if you are polite enough to first try justify that which I previously asked you to justify regarding what is real. — javra

I'm not clear on what you are asking here. Objects are "made of matter" by definition. Just as thoughts and experiences "happen to minds' by definition. We know what we mean (not in the sense of being able to offer exhaustive explanations, obviously) when we say an object is made of matter, just as we do when we say that a thought occurs in a mind. Do we know what we mean when we say that objects are made of mind, or ideas occur to matter? I don't think so.

On the other hand, I believe we do have a more or less intuitively coherent notion of God (an infinite mind), and of the idea that objects might be ideas in His mind.

Objects are "made of matter" by definition. Just as thoughts and experiences "happen to minds' by definition. We know what we mean (not in the sense of being able to offer exhaustive explanations, obviously) when we say an object is made of matter, just as we do when we say that a thought occurs in a mind. — Janus

OK, but on its own this leads to the position of Cartesian Dualism. The position does hold some logical inconsistencies at a metaphysical level of contemplation.

Do we know what we mean when we say that objects are made of mind, or ideas occur to matter? I don't think so. — Janus

Its a different outlook which, in part, entails a different understand of what constitutes real causation types. Freewill being one such different form of causation - top-down causation - which, in turn, entails teleological causation(s). So, if we're to start using this language of "objects are made of mind" first and foremost--unless one chooses to irrationally go down a solipsism mindset--this "mind-stuff of objects" ought to be duly understood to be fourth-person (not pertaining any individual mind in the sense that all idealists and materialist understand "individual minds"). The question of "whose mind is it then?" holds, at minimum, two alternatives: a) somebody's, such as being the mind of God (as you've alluded to) or, else, b) nobody's, something like "the collective phenomena-endowed mind emerging from out of the collective unconscious, to which all individual minds (similar to Jung's worldview) are in their own ways partly tied into" (hence, not the mind of God). This, of course, is painted with wide brush strokes ... and the two alternatives mentioned are not exhaustive.

On the other hand, I believe we do have a more or less intuitively coherent notion of God (an infinite mind), and of the idea that objects might be ideas in His mind. — Janus

Many do. I, personally, can't claim to so hold an "intuitively coherent notion of God (an infinite mind)". With some sober humor I intend to be good natured: Do the Jews, the Christians, or the Muslims hold the same notion of God, or do they hold three different such notions vying with each other for supremacy? And of course, there are other major religions out there, such as Hinduism and Buddhism.

The latter position, to be coherent, must posit God or some kind of universal or collective mind. That is just the point I have been making. — Janus

And without some kind of universal perceiver, the idealist has no way to justify the existence of other minds. The universal perceiver plays the role of spacetime for idealists.

What do you mean it's "the best solution" to the mind-body problem? — Agustino

It's a satisfying solution to the mind-body problem because it denies the body exists in any way transcendental to the mind.

And what does that have to do with the becoming/being dichotomy (flux)? — Agustino

Nietzsche's position is that people cling to metaphysics, especially metaphysics of eternal, unchanging, present substance, as a psychological defense mechanism against the flux of existence. Under all this wild current, there "must" be some unchanging entity that is undisturbed. Lots of religious, mystical, ethical projects are aimed at achieving some kind of contact with this substance.

Isn't that also what Buddhism says?

It's a satisfying solution to the mind-body problem because it denies the body exists in any way transcendental to the mind. — darthbarracuda

Yeah, what makes it the best? Materialism for that matter is also a "satisfying" solution because it denies that the mind exists in any way transcendental to the body. And of course, then we have positions like substance dualism, or neutral monism.

Nietzsche's position is that people cling to metaphysics, especially metaphysics of eternal, unchanging, present substance, as a psychological defense mechanism against the flux of existence. — darthbarracuda

This psychological reading of philosophy is in the final analysis pathetic. The reason is that both poles of the dichotomy can be conceived as the cause of fear. Let me give the clearest example. Atheists frequently pull out the trope that the theist believes in God because they are afraid of death and non-being. The theist, can of course, always retort that the atheist doesn't believe in God because he's afraid of having to bear eternal responsibility and accountability for his actions.

So just like the metaphysics of being is a psychological defense mechanism against the flux of existence, so too the metaphysics of becoming is a psychological defense mechanism against immutable, unchanging Being. These are of course neither arguments for nor against one metaphysics or the other. They're just red herrings.

But regardless, my original question was what does idealism have to do with flux/being? :s

Why? Do we require something to explain the separation of physical stuff? — Michael

Yes.

What separates this photon from that electron? — Michael

Time and space.
What separates this mental phenomenon from that mental phenomenon?

If you're a physicalist and believe that the mind is just brain processes (for example), do you understand idealism to be the claim that only brain processes exist? Or do you understand the claim "only mental phenomena exist" to be something else? — Michael

I don't understand the question. I understand physicalism as the claim that mental processes are brain processes and they exist, but are not the only kind of processes to exist, and idealism as the claim that only mental phenomenon exist.

You haven't done anything to clarify how mental substances are different from physical substances. To say that both viewpoints have the same problems is to say that they are the same viewpoint. WHAT is different between your view of idealism that you claim doesn't allow one to fall into solipsism, and physicalism? What makes them separate ideas?

And without some kind of universal perceiver, the idealist has no way to justify the existence of other minds. The universal perceiver plays the role of spacetime for idealists. — Marchesk

But then the idealist has to explain how it is that the universal perceiver doesn't need a perceiver themselves in order to exist. It really is no different than the problem of explaining how God doesn't need a designer for itself. Idealism is really religion in different wrapping paper.

What separates this mental phenomenon from that mental phenomenon? — Harry Hindu

Time and space. Or something else. Regardless, one can claim that only mental phenomena exists without claiming that only my mental phenomena exists.

Also, multiple bosons can occupy the same space at the same time, and yet are still separate, so your answer isn't correct.

I don't understand the question. I understand physicalism as the claim that only brain processes exist and idealism as the claim that only mental phenomenon exist.

So what are mental phenomena? If you're a physicalist then you think that mental phenomena are brain processes. So you must understand the claim "only mental phenomena exist" as the claim "only brain processes exist". Does that seem right?

You haven't done anything to clarify how mental substances are different from physical substances. — Harry Hindu

I know. I explicitly said (twice, I think) that the very notion of "substance" is vacuous.

But that's besides the point I'm making, which is the logical point that one can claim that only mental phenomena exists (whatever that is), without claiming that only my mental phenomena exists. Pluralistic idealism is a thing, and so it is simply false to assert that idealism entails solipsism. It's a strawman.

Going by idealism, and keeping it consistent, there’s no difference among you and my experiences of you. (On a non-idealist account it’s impossible for me to experience your self-awareness, since then I’d be you instead.) You = my experiences of you. But I’m not omniscient, since otherwise I’d know that I were. I don’t have to experience someone else’s self-awareness to take it’s independent existence for granted, I don’t have to become the Moon to take it’s independent existence for granted — and I learn of both much the same way, by interaction, observation, coherence, whatever. Attempting to escape solipsism by declaring that others also are selves would be textbook special pleading. There’s no more experiencing some supposed “transcendent reality” of others’ self-awarenesses than of the Moon. (For that matter, you experience someone else’s body/actions, not their mind.) The non-solipsist may have no choice but to accept others’ self-awarenesses as examples of a kind of noumena or ding-an-sich (in a very broad sense), always just over the horizon. Fortunately we have language to share our poetry. — Jorndoe

I think there is a difference here, and a case can be made for 'special pleading'. We experience the world around us as a public space, in principle accessible to others inspections/senses. "Look at that!" and we point, sort of thing. We don't infer the existence of other minds through perceiving bodies in a private space around ourselves, rather the world is pre-theoretically (or, 'before inferring') lived in as a public space, inhabited always by myself and others, as the leaders of lives, rather than us being 'masses of perceptions' lost within ourselves.

I think solipsism arises from misunderstanding the way in which others actually exist for us, seeing them as bodies - objects like the moon that can be mentally 'stripped away' into nothing more than perception, rather than as a fundamental structure of the world.

I know. I explicitly said (twice, I think) that the very notion of "substance" is vacuous.

But that's besides the point I'm making, — Michael

But that's the thing - If the notion of "substance" is vacuous, then any point you attempt to make about a particular substance is vacuous (my vs. other). The claim that you are seperate from any thing is a claim about how your substance differs from other things. If it isn't then what are you actually saying? How is it that your mind isn't other minds, or how is it that other minds aren't your mind?

So what are mental phenomena? If you're a physicalist then you think that mental phenomena are brain processes. So you must understand the claim "only mental phenomena exist" as the claim "only brain processes exist". Does that seem right? — Michael

So when a doctor opens your skull and looks at your brain, then why does he only see a brain and not your mind? Why does his mind experience a brain instead of another mind? How would he get at looking at your mind?

But that's the thing - If the notion of "substance" is vacuous, then any point you attempt to make about a particular substance is vacuous (my vs. other). The claim that you are seperate from any thing is a claim about how your substance differs from other things. If it isn't then what are you actually saying? How is it that your mind isn't other minds, or how is it that other minds aren't your mind? — Harry Hindu

What I'm taking issue with is the claim "everything is physical" or "everything is mental". The point is that it isn't even clear what it means to be physical or mental, as per Hempel's dilemma.

I'm not taking issue with the claim that there exists more than one thing.

So when a doctor opens your skull and looks at your brain, then why does he only see a brain and not your mind? Why does his mind experience a brain instead of another mind? How would he get at looking at your mind? — Harry Hindu

I fail to see how this addresses my question.

What I want to know is what the physicalist thinks the idealist means when he says "only mental phenomena exists". If the physicalist believes that mental phenomena just are brain processes then he must understand the claim "only mental phenomena exists" as the claim "only brain processes exist". Is that what the idealist means?

I don't think this is right; I think the distinction is closely related to the question of idealism vs realism. The imaginary is understood by realists to be something mental (ideal) whereas the real is considered to be something material (which is to say extra-mental).

The imaginary is understood as something perceivable only by the mind imagining it, whereas the real is something perceivable by multiple minds or even something not perceivable by any mind. The real is thus understood to be materially so.

How would you say idealists make sense of the distinction between real and imaginary? — Janus

Mathematical realists are unlikely to be materialists.

What I'm taking issue with is the claim "everything is physical" or "everything is mental". The point is that it isn't even clear what it means to be physical or mental, as per Hempel's dilemma.

I'm not taking issue with the claim that there exists more than one thing. — Michael

Then why do you keep making claims about how there is a distinction between my mind and other minds (more than one mind)? You keep veering off in different directions. I wonder if you really understand what it is that you are talking about.

My point has been that if different things interact with each other, then it is pointless to call these things "physical" or "mental". They are the same "substance" if they can interact. Period. That's all we need to know. What we label the primary "substance" is irrelevant - especially if there is no difference in how it interacts, or how it behaves when compared to claims of some other "substance" behaving and interacting the same way. We can both dispense with the terms, "physical" and "mental". They aren't necessary to make yours, or my, points. Now that you understand that it isn't necessary to use these terms, now explain to me how minds interact, without using the terms, "mental" or "physical" or "substance".

Then why do you keep making claims about how there is a distinction between my mind and other minds (more than one mind)? You keep veering off in different directions. I wonder if you really understand what it is that you are talking about. — Harry Hindu

1. The claim "only mental phenomena exists" doesn't entail the claim "only my mental phenomena exists", and so idealism doesn't entail solipsism.
2. It isn't clear what it means to be either physical or mental, and so physicalism and idealism are nebulous notions.

My point has been that if different things interact with each other, then it is pointless to call these things "physical" or "mental". They are the same "substance" if they can interact. Period. That's all we need to know. What we label the primary "substance" is irrelevant - especially if there is no difference in how it interacts, or how it behaves. We can both dispense with the terms, "physical" and "mental". They aren't necessary to make yours, or my, points. — Harry Hindu

Then physicalism and idealism are identical. They both just assert "all things interact with each other".

They'd also be false, given that some things can't interact with other things (e.g. light and dark matter).

Now that you understand that it isn't necessary to use these terms, now explain to me how minds interact.

How do bodies (or at the smaller scale, particles) interact?

The question of causation is a question for everyone.

Then physicalism and idealism are identical. They both just assert "all things interact with each other". — Michael

So materialists and idealists are one and the same and have no idea that they have been arguing for the same thing all of these centuries?

They'd also be false, given that some things can't interact with other things (e.g. light and dark matter). — Michael

And that needs to be explained - why some things can interact and some things can't - again without using terms like "substance" (because, according to you, it is a vacuous term), or "physical" or "mental".