Few years back I found myself working with fiesty philosophy graduate and earned some contempt when I let slip that I might be a panpsychist. "So you believe that table is sentient?" he barked in the staffroom. In reality I slunk away in embarrased silence.

These days I'd hope to at least say "Not right right now, but just wait around a bit will you?". The point being that over time pretty much all atoms will get a go as they're cycled through the system. The table-form we were looking at was just a temporal anomaly really.

So there's the time dimension to consider too.

pZombies ....It was Insane denial of the purpose of Consciousness. — SteveKlinko

Lol, my first uni study was Psychology run by a rampant B.F Skinner loving behaviourist who would have no truck with the mention of any mental states. Oddly, he was also a rampant Freudian.
Strange world this one.

Could it be the case that the so-called "hard problem of consciousness" is nothing more than a consequence of ill-conceived notions?

I think so.

"Experience" being a central one. "Consciousness" being the main one. The "subjective/objective" dichotomy being another pivotal one. All three are involved. None of them are adequate for taking account of what's going on in the minds of thinking and/or believing creatures...

By the way, if there's anyone reading this who is worried they might actually be a pZombie themselves, please don't hesitate to share your feelings about it here!

Could it be the case that the so-called "hard problem of consciousness" is nothing more than a consequence of ill-conceived notions?
"Experience" being a central one. "Consciousness" being the main one. The "subjective/objective" dichotomy being another pivotal one. All three are involved. None of them are adequate for taking account of what's going on in the minds of thinking and/or believing creatures...
— creativesoul

Yeah, that notion got kicked around a lttle yesterday I think

AFK for a time guys. Sorry for any lack of responses

You're right, I could be clearer in expressing my concerns. I think the issue I'm worried about has the principle of sufficient reason at its core. I'll have another go at explaining my confusion more clearly.

Let's suppose you believe that reality consists of two realms, we can neutrally call them realm A and realm B. If they are genuinely two distinct realms, then they are self-contained insofar as all the elements in one realm can be accounted for in terms only involving other elements of that same realm. This is real dualism about reality.

However, realm A becomes epiphenomenal with regard to realm B and vice-versa. But the principle of sufficient reason would then require us, from the perspect of realm B, to reject the existence of realm A, since realms that just "tag along for the ride" have no sufficient reason for existing. Similarly, the principle of sufficient reason would require us to reject the existence of realm B when considering things from realm A. We might want to try to take a third way, but we are assuming that reality just consists of two realms, so there is no third realm we can go to for adjudication.

So, we then suppose that realm A and realm B are not separate realms. We might think that everything we previously presumed to be in realm A can be accounted for by things in realm B, or vice-versa, but we thus eliminate one of the two realms we presumed to exist in the first place. We might want to try an approach that said that there is at least one thing in what we used to call realm A that cannot be accounted for by things in realm B, but then we are just keeping realm A as a self-contained realm, but with a shrunken domain, and once again from the perspective of the enlarged realm B, it becomes epiphenomenal and so its raison d'être is removed. And similarly, from the perspecive of this reduced realm A, realm B is redundant.

So, the principle of sufficient reason pushes us towards monism.

There might be some conceptual confusion going on in the above, maybe in my assumption that if reality consists of two realms, then the principle of sufficient reason is applicable in both realms individually. But if the alternative is to say that the principle of sufficient reason has to be applied from neither realm A nor realm B, then we seem to have two choices. First, we could suppose that the principle is to be applied from a perspective in reality. But then we have have to introduce a third realm to reality, and the same line of thought as applied above to realm A and realm B would reapply to realm A + realm B + realm C, and the pressure for monism remains. Alternatively, we could try the line that the principle of sufficient reason is not to be applied from any perspective in reality at all, but that requires that we be able to make a distinction between not applying a principle from within reality, on the one hand, and not really applying the principle at all, on the other, but that smells like a distinction without a difference.

↪Metaphysician Undercover You're right, I could be clearer in expressing my concerns. I think the issue I'm worried about has the principle of sufficient reason at its core. I'll have another go at explaining my confusion more clearly.

Let's suppose you believe that reality consists of two realms, we can neutrally call them realm A and realm B. If they are genuinely two distinct realms, then they are self-contained insofar as all the elements in one realm can be accounted for in terms only involving other elements of that same realm. This is real dualism about reality.

However, realm A becomes epiphenomenal with regard to realm B and vice-versa. But the principle of sufficient reason would then require us, from the perspect of realm B, to reject the existence of realm A, since realms that just "tag along for the ride" have no sufficient reason for existing. Similarly, the principle of sufficient reason would require us to reject the existence of realm B when considering things from realm A. We might want to try to take a third way, but we are assuming that reality just consists of two realms, so there is no third realm we can go to for adjudication.

So, we then suppose that realm A and realm B are not separate realms. We might think that everything we previously presumed to be in realm A can be accounted for by things in realm B, or vice-versa, but we thus eliminate one of the two realms we presumed to exist in the first place. We might want to try an approach that said that there is at least one thing in what we used to call realm A that cannot be accounted for by things in realm B, but then we are just keeping realm A as a self-contained realm, but with a shrunken domain, and once again from the perspective of the enlarged realm B, it becomes epiphenomenal and so its raison d'être is removed. And similarly, from the perspecive of this reduced realm A, realm B is redundant.

So, the principle of sufficient reason pushes us towards monism.

There might be some conceptual confusion going on in the above, maybe in my assumption that if reality consists of two realms, then the principle of sufficient reason is applicable in both realms individually. But if the alternative is to say that the principle of sufficient reason has to be applied from neither realm A nor realm B, then we seem to have two choices. First, we could suppose that the principle is to be applied from a perspective in reality. But then we have have to introduce a third realm to reality, and the same line of thought as applied above to realm A and realm B would reapply to realm A + realm B + realm C, and the pressure for monism remains. Alternatively, we could try the line that the principle of sufficient reason is not to be applied from any perspective in reality at all, but that requires that we be able to make a distinction between not applying a principle from within reality, on the one hand, and not really applying the principle at all, on the other, but that smells like a distinction without a difference. — jkg20

Let Realm A be the Conscious Realm where all our Conscious experiences happen. We can put all Conscious experience in it's own Realm because we don't know what Conscious experience is yet. For example Science does not say anything about what the experience of Red is. At this point it just Is. So it makes sense to put it into a separate Realm.

Let Realm B be the Scientifically known Physical World of Material, Energy, and Space. The Brain can produce Neural Activity for the color Red while we are Awake or while we are Dreaming. This Red Neural Activity can produce a Conscious Experience of Red in the Conscious Mind. This Red Neural Activity is the Neural Correlate of the Conscious experience of Red.

So we know two things:

1) Neural Activity for Red happens in Realm B.
2) A Red Conscious experience happens in Realm A.

But the obvious question jumps out at us: How does 1 lead to 2? Just because 2 is Correlated with 1 doesn't mean that they are both in the same Realm. There is a Huge Explanatory Gap between 1 and 2. This is the Hard Problem of Consciousness.

At this point the experience of Red for example is not understood by Science. In fact Science has no idea what it is. It is truly one of unsolved Mysteries of Science. The only thing that Science has come up with is that it is an Illusion. So how do we experience that Illusion? The Red experience must be explained.

But the Conscious Visual experience consists of all the Colors. These Colors are painted onto that Conscious Visual screen that is embedded in the front of your face that you probably don't even think about. But that is what you should be thinking about. If you think about the Conscious Visual experience and specifically the color Red you will eventually understand the Mystery of it and you will become a Dualist.

So look at something Red. Think about the Redness of the Red. What is that? That Redness is a Property of the Conscious experience of Red. The Redness Property only exists in Realm A. There is no Property of Redness in Realm B. All there is, is Neural Activity. But even the Physical Red Light that causes all this from Realm B does not have a Property of Redness. Realm B Red Light has Wavelength as a Property. The Conscious Red experience does not have Wavelength as a Property only Redness.

.

Let's suppose you believe that reality consists of two realms, we can neutrally call them realm A and realm B. If they are genuinely two distinct realms, then they are self-contained insofar as all the elements in one realm can be accounted for in terms only involving other elements of that same realm. This is real dualism about reality. — jkg20

To separate two things as "distinct" things, does not require that those things do not interact with each other. You and I are distinct things yet we are interacting here. So I think you are placing unnecessary restrictions on your definition of "genuinely" distinct. If that is what is required to be genuinely distinct, then absolutely nothing could be genuinely distinct from anything else, because it would have to be self-caused. So that definition of "distinct" is unreal and unacceptable. We ought to allow that distinct things may interact with each other.

But the principle of sufficient reason would then require us, from the perspect of realm B, to reject the existence of realm A, since realms that just "tag along for the ride" have no sufficient reason for existing. — jkg20

I don't see how you bring the principle of sufficient reason to bear in this way. What you have described is simple solipsism. You are suggesting that I must reject the reality which you apprehend with your mind, because my apprehended reality is the only true reality. But since I can recognize that your perspective is different from mine, there is no real reason for me to reject yours. From my perspective, you might "tag along for the ride", but from yours, I might "tag along for the ride". So you haven't given sufficient reason to reject one or the other.

So, we then suppose that realm A and realm B are not separate realms. — jkg20

It is only by your assumption of a third realm that you claim A and B are not separate. As I explained above, A and B may be distinct, and interacting. When you give reality to this "interacting", you make A and B parts of a larger whole, C, which contains this interacting. But there is no necessity to assume C. There is simply A interacting with B and the reality of the interactions is accounted for by the activities of A and the activities of B.

This is why there appears to be a "problem" of consciousness. We keep assuming that if A and B interact, the "interaction" itself ought to be evident. So we look for the interaction. But this is a mistaken procedure because the assumption of this third realm, the realm of interaction, is not supported logically. there is no need to assume a realm of interaction. We have activity occurring in A, and activity occurring in B. Some of the activity in A might be the cause of some activity in B, and vise versa. There is no need to assume C, the realm of interaction, unless your intent is to make A and B two parts of a larger whole, C. But that is simply the intent to reduce the two distinct realms to one realm, C. It is a monist intent. If the realm of interaction is not supported by evidence, then this is an incorrect procedure, and the monist intent is a misguided attempt to simplify what cannot be simplified..

To separate two things as "distinct" things, does not require that those things do not interact with each other. You and I are distinct things yet we are interacting here. So I think you are placing unnecessary restrictions on your definition of "genuinely" distinct. If that is what is required to be genuinely distinct, then absolutely nothing could be genuinely distinct from anything else, because it would have to be self-caused. So that definition of "distinct" is unreal and unacceptable. We ought to allow that distinct things may interact with each other.

The metaphysical issue concerns distinct realms, not distinct things within realms. You and I are distinct things, perhaps, but we are not in distinct realms. Metaphysical dualism requires two distinct realms, and the only way I can see of fleshing out the notion of separate realms is in terms of self-containment. That things within the same realm might interact with each other is unproblematic (or at least less problematic) but that things might interact across realms is precisely the issue I'm trying to dive into at an abstract level. Descartes, for instance, gets into trouble at this point - he believes he has established the existence of two distinct realms (he calls them "substances"), the mental and the physical, but if they are genuinely distinct, how can they possibly interact? Of course, Descartes just assumed that they did interact, rather than pursuing the idea that the very notion of two distinct metaphysical realms interacting does not make sense in the first place (which I think is one of the issues Spinoza has with Descartes).

Let Realm A be the Conscious Realm where all our Conscious experiences happen. We can put all Conscious experience in it's own Realm because we don't know what Conscious experience is yet. For example Science does not say anything about what the experience of Red is. At this point it just Is. So it makes sense to put it into a separate Realm.

I suppose I'm trying to approach the issue purely metaphysically, not epistemologically (and therein may lie my confusion). That we might not know enough about which realm a given thing should be assigned to seems to me to be a different issue from pursuing the very idea of two metaphysically distinct realms in the first place. Whilst am happy to assume that what there is might have an effect on what we can know, I'm less inclined to believe that what we can know might have an effect on what there is. But maybe I'm making the kind of mistake here that Kant thought he'd analysed and treated in his Critique of Pure Reason.

Descartes, for instance, gets into trouble at this point - he believes he has established the existence of two distinct realms (he calls them "substances"), the mental and the physical, but if they are genuinely distinct, how can they possibly interact? — jkg20

:up: Yes indeed, and oh look, is that Idealism I see entering the stage, rearing its headless Mind?

Metaphysical dualism requires two distinct realms, and the only way I can see of fleshing out the notion of separate realms is in terms of self-containment. — jkg20

I'll reiterate. This is not what "distinct" means. Your premise that distinct realms must be "self-contained" is simply designed to support your monism. It is begging the question.

There is no logical reason for you to insist that one distinct realm cannot interact with another distinct realm. It appears like you have not read my entire post.

Don't get me wrong, I'm neither a monist nor a dualist, I'm just curious. So how does one define distinctness of metaphysical realms if not in terms of self-containment of that realm? Perhaps I'm overlooking something in your post, but I don't see a definition.

... @jkg20 Perhaps the descriptor 'apparently' distinct realms would be pertinent here. The realm of mind being not other than its phenomenal, experiential appearances, in some sort of self-observing sense, echoing the revelation of Buddhism that formlessness is not other than form, but within the context of Idealism.

OK, but by introducing the notion of appearances into the definition of metaphysical realms, the suggestion appears to be that what we can know puts a limit on what there is. Is that what you intend, or have I misunderstood the suggestion?

Yes, to elaborate, it implies that what a 'finite' locus of mind can only know as experiential phenomenal appearances, by definition, is a limitation imposed upon what would be the potentially infinite emanations of Mind-at-large. As if it is the trade-off, so to speak, for the sake of this relational experience.

It is only by your assumption of a third realm that you claim A and B are not separate. As I explained above, A and B may be distinct, and interacting. When you give reality to this "interacting", you make A and B parts of a larger whole, C, which contains this interacting. But there is no necessity to assume C. There is simply A interacting with B and the reality of the interactions is accounted for by the activities of A and the activities of B.

This is why there appears to be a "problem" of consciousness. We keep assuming that if A and B interact, the "interaction" itself ought to be evident. So we look for the interaction. But this is a mistaken procedure because the assumption of this third realm, the realm of interaction, is not supported logically. there is no need to assume a realm of interaction. We have activity occurring in A, and activity occurring in B. Some of the activity in A might be the cause of some activity in B, and vise versa. There is no need to assume C, the realm of interaction, unless your intent is to make A and B two parts of a larger whole, C. But that is simply the intent to reduce the two distinct realms to one realm, C. It is a monist intent. If the realm of interaction is not supported by evidence, then this is an incorrect procedure, and the monist intent is a misguided attempt to simplify what cannot be simplified — Metaphysician Undercover

When I see that a Phenomenon in A is correlated with a Phenomenon in B I just naturally ask how does this happen? The Correlations are predictable and consistent enough that we must assume there is some kind of causal Interaction between A and B. I think we need a C Realm, at least as a place holder, for the Interaction to take place in. Obviously when we better understand what Consciousness is, Realm C will roll into the other two Realms, or the 3 Realms may all roll into one Realm. I think we really need this Realm C to keep us concentrating on what the problem really is. I think it is a Connection Problem and a Processing Problem.

So how does one define distinctness of metaphysical realms if not in terms of self-containment of that realm? Perhaps I'm overlooking something in your post, but I don't see a definition. — jkg20

I don't see how "self-containment" is even relevant. I would think that if the descriptive terms used to describe the properties or attributes of the members of one realm are distinct from, and not reducible to the descriptive terms of the other, then the two are distinct.

Perhaps the descriptor 'apparently' distinct realms would be pertinent here. The realm of mind being not other than its phenomenal, experiential appearances, in some sort of self-observing sense, echoing the revelation of Buddhism that formlessness is not other than form, but within the context of Idealism. — snowleopard

No I wouldn't agree. The whole point I am arguing is that the distinction is real, not apparent.

The Correlations are predictable and consistent enough that we must assume there is some kind of causal Interaction between A and B. I think we need a C Realm, at least as a place holder, for the Interaction to take place in. — SteveKlinko

The C realm here is completely imaginary. What is real is the activity of A and the activity of B. That there is a "causal interaction" is your description, so it is something which is completely a product of your mind, imaginary. If you want to assign "reality" to this causal interaction you would need to base it in something real, independent of your mind. You could assign reality to the passing of time, to make the causal interaction real, but this is not introducing another "realm", it is just assuming that the passing of time is real, and is common to both realms.

I think we really need this Realm C to keep us concentrating on what the problem really is. — SteveKlinko

Do you agree, that the passing of time satisfies the conditions required of the place holder (realm C)? We do not need the realm C as a place holder if the passing of time is real and common to both A and B, allowing for causal relations.

No I wouldn't agree. The whole point I am arguing is that the distinction is real, not apparent. — Metaphysician Undercover

Well then this may be one of those cases of having to agree to disagree. I fully concede that, not being a formally educated philosopher, I am coming at this more from the perspective of mysticism, via the lens of Buddhism/Taoism, that has evolved over time into this version of Idealism, perhaps akin to dual-aspect or dialetical monism, which may be a bit too numinous for some here. Nonetheless, I remain open to being otherwise enlightened -- although I may now have to shut the door on physicalism -- in this cyberspace crucible of cogent thinkers, such as @jkg20 and others, wherein I can put these ideas to the test of tenability. So far, it remains a work in progress.

I don't see how "self-containment" is even relevant. I would think that if the descriptive terms used to describe the properties or attributes of the members of one realm are distinct from, and not reducible to the descriptive terms of the other, then the two are distinct.

Doesn't that miss jkg20's point? After all, the way you make this statement assumes you've already settled that there are two realms for different attributes to apply in. Jkg20, as far as I can tell, is posing some very abstract metaphysical questions (metametaphilosophical ?) concerning making the kind of divisions that some people are kind of helping themselves to.
One approach, and perhaps this was more like what you are getting at, is to say the dualism issue isn't about two distinct realms at all, but just about two distinct kinds of attributes that are possessed by things that are in one and only one realm. You kind of cede to monism in doing that at some level, but perhaps can keep some form of dualism going at the level of properties, although perhaps even there jkg20's abstract issues about realms and epiphenomenalism/principle of sufficient reason might crop up (in a recast form perhaps).

Yes, to elaborate, it implies that what a 'finite' locus of mind can only know as experiential phenomenal appearances, by definition, is a limitation imposed upon what would be the potentially infinite emanations of Mind-at-large. As if it is the trade-off, so to speak, for the sake of this relational experience.

I've nothing against speculative philosophy, as opposed to the dry analytic kind that jkg20 seems more focussed on, but there's some terminology in what you say that does cry out for clarification before someone like me could even begin to understand what you're talking about. I suppose for "finite locus of mind" you mean something like the traditional "subject of experience"? But what is this "Mind-at-large", you mention, and what are its emanations?

Do you agree, that the passing of time satisfies the conditions required of the place holder (realm C)? We do not need the realm C as a place holder if the passing of time is real and common to both A and B, allowing for causal relations.

If the idea is that realm C contains the necessary and sufficient conditions for causal occurences, the passing of time won't cut it. Time passing might be necessary for causation, but since we can imagine nothing happening over a period of time, it is not sufficient.

Mind-at-large was coined by Aldous Huxley to refer to some unitary state of Mind, which may be made clearer in the context of this statement: "In the final stage of egolessness there is an 'obscure knowledge' that All is in all—that All is actually each. This is as near, I take it, as a finite mind can ever come to perceiving everything that is happening everywhere in the universal Mind at large" In the version of Idealism I'm pondering, Mind would be the ontological primitive. Its ideated 'emanations' (though this may not be the ideal word) would be likened to Platonic ideas/forms. So to use an analogy, such 'emanations' would not be apart from this unitary Mind, in the same sense that waves are not apart from an ocean. However, the analogy can't be extended beyond that.

The Correlations are predictable and consistent enough that we must assume there is some kind of causal Interaction between A and B. I think we need a C Realm, at least as a place holder, for the Interaction to take place in. — SteveKlinko
The C realm here is completely imaginary. What is real is the activity of A and the activity of B. That there is a "causal interaction" is your description, so it is something which is completely a product of your mind, imaginary. If you want to assign "reality" to this causal interaction you would need to base it in something real, independent of your mind. You could assign reality to the passing of time, to make the causal interaction real, but this is not introducing another "realm", it is just assuming that the passing of time is real, and is common to both realms. — Metaphysician Undercover

The Physical Realm is real and the Conscious Realm is real. The Interaction is completely real, we just don't know what it is yet.

I think we really need this Realm C to keep us concentrating on what the problem really is. — SteveKlinko
Do you agree, that the passing of time satisfies the conditions required of the place holder (realm C)? We do not need the realm C as a place holder if the passing of time is real and common to both A and B, allowing for causal relations. — Metaphysician Undercover

Just because Causal Processes can happen over time doesn't mean you don't need a C Realm. Any Causal Process of the C Realm must deal with Physical Realm Activity and translate that to Conscious Realm Activity. Maybe these Causal Processes are in Realm A and Realm B but somehow a Bridge between Realm A and B must be constructed.

One approach, and perhaps this was more like what you are getting at, is to say the dualism issue isn't about two distinct realms at all, but just about two distinct kinds of attributes that are possessed by things that are in one and only one realm. — ProcastinationTomorrow

I don't think that this really resolves the issue. The issue is not that we can make two different types of descriptions concerning the same thing, it is that some things require one type of description, and other things require another type of description. So the things get placed in different categories. Consider that there are concepts, which are immaterial objects, universals, and there are also physical things which are material objects, particulars. Do you see how it is not the case that the two different types of descriptive terms can be applied to things of both classifications, but it is the case that the things require a different type of description, and this necessitates the distinction?

If the idea is that realm C contains the necessary and sufficient conditions for causal occurences, the passing of time won't cut it. Time passing might be necessary for causation, but since we can imagine nothing happening over a period of time, it is not sufficient. — ProcastinationTomorrow

That's exactly why the argument from sufficient reason doesn't hold as a valid argument. Activities in realm A may be causing activities in realm B, but the determination that the activities in realm B are posterior in time to the activities in realm A doesn't suffice to prove that the one is the cause of the other. So it may still be the case that activities of realm A cause activities of realm B, without any realm C. The realm C is just required to prove that the one causes the other. It is the proof which requires this unity of coherency between the two realms. However, in order that activities in realm A may cause activities in realm B, the passage of time must be common to both, because "cause" implies a temporal succession

Just because Causal Processes can happen over time doesn't mean you don't need a C Realm. Any Causal Process of the C Realm must deal with Physical Realm Activity and translate that to Conscious Realm Activity. Maybe these Causal Processes are in Realm A and Realm B but somehow a Bridge between Realm A and B must be constructed. — SteveKlinko

As I explained above, the "Bridge", which is realm C is not necessary. The realm C is only required to prove a causal relation. Realm A and realm B be may be causally interactive without any realm C. The so-called "Bridge" is just needed to understand the causal relation. However, since understanding is already a property of the one realm, let's say realm A, the Bridge would be entirely within realm A, principles of understanding, and not a real bridge, nor a realm C, at all.

This is the real problem of consciousness. We assume a material, physical, world, a realm which is outside the realm of consciousness. But we have no real way to understand it because everything which we understand is within the realm of consciousness. So we poke and prod at this material world, observing how it behaves in response, but we can only make conclusions based on a supposed causal relation, because we haven't discovered any real Bridge. There may not actually be a Bridge, and any constructed Bridge would just be within realm A, and only a false Bridge

↪Metaphysician Undercover

I don't see how "self-containment" is even relevant. I would think that if the descriptive terms used to describe the properties or attributes of the members of one realm are distinct from, and not reducible to the descriptive terms of the other, then the two are distinct.

Doesn't that miss jkg20's point?

Yes, I think so - in any case I'm still waiting for a definition of distinctness of realms in terms other than self-containment. However, your point about the dualism issue possibly making sense when shifted to talk of properties rather than realms is food for thought - I'll have to think about that - but I initially I think my general point could be recast.

Assume two distinct realms, be it properties or substances or whatever: what makes them distinct? You cannot just help yourself to the fact that they are distinct (well, you could, but then you wouldn't be doing metaphysics). So, you try to move forward by providing necessary and sufficient conditions for something to be in one of the realms or the other. But, if they are not strictly logically contradictory conditions, how do you rule out the possibility of one thing meeting the necessary and sufficient conditions for being in both realms, and thus destroying their distinctness? Because, one wants to insist, precisely because the realms are distinct - but then we are back to where we began - we're just asserting and not establishing distinctness. So, we shift the abstract definition of distinctness a little more and we add the condition that the realms are self-contained - but what does that add? What it adds, at least under one expansion of the idea, is that the items in distinct realms could exist in the absence of all items in any other possible realm, which clearly excludes the idea of one thing being in two actual realms, because one thing cannot exist in its own absence. And now here comes the principle of sufficient reason (which, incidently, is not uniquely concerned with causation). The principle of sufficient reason simply states that only that exists for which there is a reason why it exists (the reason may be a cause, but it may be something other than a cause). But now suppose we adopt the perspective of one of these mooted self-contained realms. All things in it exist independently of any other realm. So, what would motivate, from the perspective of this realm, the idea that there might even be another realm at all? Since this realm is self-contained, there is no causal dependence of this realm on any external realm. Also, if we suggest that a second realm might be the causal offshoot of this realm, the principle of sufficient reason reapplies - why would there be such an offshoot if nothing within this realm requires it? We might try to look for non-causal connections between realms that could answer the demands of the principle of sufficient reason, but even though not all reasons are causes, I'm not sure whether a non-causal reason would fare any better at giving (from the perspective of one realm) a sufficient grounds for the existence of another realm. Having said that, it's entirely possible that there are options that have not crossed my mind.
So, the next move is to say that the principle of sufficient reason should not be applied from the perspective of any given realm, and so has no bite in this line of thought. But is it possible to apply that principle without applying it from some realm or another? This is a genuine question, not a rhetorical one, by the way.
Alternatively, we ditch the principle of sufficient reason entirely - but, since that is (arguably) the principle that motivates all science and philosophy (if you make a difference between the two) that seems a little drastic and possibly self-stultifying.
So, I remain currently unconvinced that dualism is a genuine alternative to monism.

So, what would motivate, from the perspective of this realm, the idea that there might even be another realm at all? — jkg20

I hope I can illustrate a slightly different perspective on this question for you. I take the sense of 'domains' when applied to this question to be in some sense allegorical. Think of 'the domain of natural numbers' or 'the domain of physical law'. The domain of natural numbers is real - 2 is part of it, the square root of two is not. But there is no literal domain in the sense of a separate realm. The reason I add that qualification, is that I think there is an overwhelming urge to ask, of a domain, 'where could it be?' But obviously such 'domains' are not spatially located.

In any case, a rough definition of what I understand as the 'intelligible domain' is precisely the domain of such things as numbers, logical laws, natural laws, conventions, and the like. There are things which can only be grasped by a rational intelligence, i,e. a mind capable of counting, reasoning and so on. So in answer to the question 'what is rational intellect?' the answer is 'the faculty which is capable of grasping such ideas.'

Now that is very different from the way 'mental substance' is usually depicted, but I think this is because the sense of 'mind-substance' is indeed fatally mistaken. It's not a ghostly ethereal stuff or protoplasmic entity. I would say the appropriate analogy is that of the relationship between words and meaning. The same idea can be expressed in any number of languages, or indeed in any number of media. So 'the idea' is nearer in meaning to 'geist' or 'spirit', than an 'ethereal thinking substance'. Or rather, it is the 'substance' in the sense of the 'substance of the idea' or 'the gist' of something.

More could be said but I will leave it there, along with a reference to a paper I have found helpful, Frege on Knowing the Third Realm, Tyler Burge

Thanks Wayfarer - I'll take a look at that paper: I've heard of Tyler Burge in other contexts (externalism in the philosophy of mind) but have not read any of his papers. However, I think even the examples you gave might run up against the principle of sufficient reason (PSR) line of thought. Let's suppose our two distinct realms are the abstract and the particular. If we apply the PSR from the point of view of the abstract realm, no need for particulars, so no particulars. If we apply the PSR from the point of view of the particulars realm, no need for abstract objects, so no abstract objects. So the pressure remains to get rid of one or both realms. I think perhaps for me the issue for dualisms of all kinds is to find some substantial notion of a connection between the two posited realms which on the one hand satisfies the PSR, showing why there must be not only one, but two, whilst at the same time not collapsing the fact that they are genuinely distinct and not really just one thing disguised as two.

Now that is very different from the way 'mental substance' is usually depicted, but I think this is because the sense of 'mind-substance' is indeed fatally mistaken. It's not a ghostly ethereal stuff or protoplasmic entity. I would say the appropriate analogy is that of the relationship between words and meaning. — Wayfarer

So, I remain currently unconvinced that dualism is a genuine alternative to monism. — jkg20

This really does speak to the most profound implication of Idealism: that there is no ethereal substrate producing any substance. That which emanates these cosmic ideas/forms, as in its sapient analog, i.e. us, is more like how one's imaginative mind conceives of a language, or even a poem -- it is an entirely cognitive event. And more and more, as I read these comments -- especially in @jkg20 's most recent reply to @ProcastinationTomorrow making the case for monism -- I can only deduce (although it's now becoming one's direct experience) that there is but one realm, one boundless 'container,' by whichever preferred name: That which emanates these cosmic ideas/forms. So to pick a name, say Awareness, everything that is conceived, imagined, perceived, experienced, without exception, is contained within that Awareness, including even the apparency of a subject/object divide. As Wheeler put it ... "There is no 'out there', out there".