If the non-mental does interact with the mental however, that raises questions as to how that is even possible. — Ø implies everything

You might start with the simplified question of how any sort of interaction is possible.

Define your terms (how you intend for us to use them for the sake of this discussion): mental, non-mental, interaction, ontological idealism. This might be halpful ...

You are explaining idealism as dualistic. In your explanation the mental and the non-mental are two and thus interaction has to be explained.
As I understand idealism, all is mental. The non-mental is an expression of the mental.
Like the water surface and the ripple, the mental is the water (all there is) and the ripples are the non-mental (water excited).

Hello 0 implies everything,

I have not found any proof/argument of how it is impossible for the non-mental to interact with the mental

It sounds like you may be referring to the “problem of interaction” for substance dualists; and the argument is founded on the acceptance of substratum theory (and so is the stereotypical subtance dualist position): simply put, substratum theory is the conjecture that properties require a substance to bare them. In other words, properties are bore by a “bare particular” which is distinct from the properties themselves. For example, from a substratum theorist perspective, the properties of a chair (e.g., material, color, etc.) are bore by a bare particular which is the compresence for the chair’s properties. This is how they would explain how objects have properties which are “tied” or “glued” to themselves as opposed to being “floating” properties.

This is where the idea of a “substance” comes from in philosophy of mind: it is the ultimate substrate which bears all the properties of that “type”.

Under this substratum theory, originates the first fundamental distinction in philosophy of mind: qualitative (i.e., pertaining to “types” of substances) vs. quantitative (i.e., pertaining to “tokens”, or “how many”, compose fundamentally reality within each “type” of substance) considerations. With respect to the former, here are the basic distinctions:

Qualitative:

Monism: there is one “kind” of substance.
Pluralism: there are three or more “kinds” of substances.
Dualism: there are two “kinds” of substances.


Within the latter:

Quantitative:

Monism: there is only one “thing” within and of the “kind” of substance (in question).
Pluralism: there are three or more “things” within and of the “kind” of substance (in question).
Dualism: there are two “things” within and of the “kind” of substance (in question).

Sometimes the “thing” is referred to as a “token”.

Now, within philosophy of mind, under this substratum theory, there are five main (stereotypical) categories of views:

1. Physicalism (also sometimes used synonymously with materialism): a qualitative monist, quantitative pluralist view whereof the “kind” of substance is physical (or matter, depending on how the terms are hashed out) and there is fundamentally many of that “kind” which make up the real world.

2. Property Dualism (also sometimes called irreducable materialism/physicalism): a qualitative monist, quantitative pluralist view whereof there is one “kind” of substance which is physical but the mental is irreducable (somehow) to the physical (i.e., strong emergence) and there is fundamentally many of this “kind” which make up reality.

3. Substance Dualism: a qualitative dualist, quantitative pluralist view whereof there are two “kinds” of substances which are physical and mental and there is fundamentally many of both “kinds” which make up reality.

4. Idealism: a qualitative monist, quantitative monist view whereof there is one “kind” of substance which is mental and there is one “thing” which fundamentally constitutes reality (which is usually God).

5. Non-dualism: a qualitative pluralist, quantitative monist view whereof there are three or more “kinds” of substances which are usually mind, matter, and an unknown God-like unifying substance; and it is usually one “thing” which fundamentally constitutes reality (usually God in a pantheistic sense).

Now, I want to note that these are just stereotypical, basic definitions and many people will not fit nicely into them. For example, I am a subjective idealist (more or less), and definitely am not a quantitative monist. So do what you will with those definitions: I just thought it may be useful.

In terms of the interaction problem, by definition two substances have no communal attributes (as they are two fundamentally different “kinds” of existence): so one “kind” cannot, by definition, have any interaction with the other “kind” unless one is positing that two things can interact without sharing at least one communal property.

In terms of arguments for idealism, I will briefly elaborate on the argument from introspection and parsimony:

When one introspects upon their experience (which is consciousness), they will begin to realize that every object within their experience is wholly reducible to a collection of sensations. Now, unless there is a reason to posit conceptually external (consciousness-independent) objects to explain the data of one’s experience, then by occam’s razor one ought to hold Idealism over the other positions because it is more parsimonious (i.e., it explains the same data with less entities). The million dollar question you must ask yourself is thusly this: do you need to posit (conceptually) a consciousness-independent object to explain any data within your experience? If not, then Idealism is for you. If you do, then it is not for you.

Now, what your argument seems to be what is sometimes called a “malicious” argument (although I don’t find it such at all) that even if there was hypothetically a non-mental substance somehow, from the perspective of the subject it would still be all consciousness and they wouldn’t ever need to conceptually posit consciousness-independent objects (even if there actually were some). To some extent, I sympathize with the view because I, likewise, do not think I can rule out there being something non-mental nor that the non-mental isn’t, from a transcendent perspective, physical (or neither or what have you) because I do not subscribe to substratum theory.

Bob

I find your qualitative/quantitative typology to be a bit imprecise. For example, idealism is often a priority monism (one basic concretum, which is God), but typically not an existence monism (one concretum, i.e. it has no proper parts). Perhaps I am wrong on that, but either way, I'm sure you see the importance in differentiating between priority and existence monism.

I am familiar with the argument from parsimony, and although I find myself somewhat agreeing with it from a pragmatic point of view, I am in the enterprise of creating a theory of absolute certainty. Thus, making ontological assumptions based on pragmatic considerations is not really what I am about.

Furthermore, the argument from parsimony is not an argument for how it is impossible for the mental and non-mental to interact; instead, it is an argument for how it is unlikely and/or how it is most economical to assume they do not, one the basis of the how it is uneconomical to posit/unlikely that the non-mental exists.

You are right. I am looking into causality right now in order to construct an informed question regarding what theories regarding its fundamental nature exists.

Well, mental and non-mental are not really definable through words (even if they can be sub-divided); they are understood intuitively, via pointing. That is, to ground mental for you, I simply ask you to direct your attention to the percepts, thoughts and emotions you are feeling right now. Qualia, and the sorts. That is the mental. The non-mental is simply the negation of that; whatever that does not fall within that categorization of reality.

I used interaction in the straight-forward sense that everyone uses it; not sure there is any other way. Interaction is present if the behavior of a thing is altered by the co-existence of another thing.

Ontological idealism is the claim that all of reality consists solely of the mental, as opposed to epistemological idealism, which is the claim that all we can know of reality is (that of) the mental.

The argument regarding the problem of interaction concedes the possibility of the non-mental, yes, and thus concedes the possibility of a substance dualism of super-reality. However, the argument also argues that such a dualism is irrelevant to everything anyways, and that reality is idealist. That is, the ontology that the argument argues for would be practically identical to a purely idealist ontology.

What are some good arguments for ontological idealism? — Ø implies everything

I'm not what anyone would call an idealist in the philosophical sense, but I do see value in using that kind of approach. In order to do math or logic, you would have to be able to see the world through idealist lenses. Also, although I am mostly drawn to pragmatic approaches with a bit of materialism mixed in, I often find myself drawn to more idealist elements - honor, human rights, fairness, kindness.

Then why add to the problem of interaction in the first place? Sound like mental gymnastics.

The whole point of the argument appealing to the problem of interaction is to argue that interaction between the mental and non-mental is impossible. Thus, even if the non-mental exists, it does not affect us and could, in one sense of the word, be called unreal. The argument basically says there are two possibilities:

1. The non-mental does not exist.
2. The non-mental does exist, but it cannot interact with the mental at all.

Both of these possibilities are practically identical, but to arrive at 2., one must invoke the problem of interaction. Basically, it side-steps the issue of proving the non-mental non-existent by arguing that it does not matter whether it exists.

I understand and it's a good philosophical argument I just don't need the roundabout-ness of it.

In order to do math or logic, you would have to be able to see the world through idealist lenses. — T Clark

I would disagree. In order to do classical mathematics or certain types of logic, one has to view it through the lens of Platonic forms (or some other non-mental, non-physical substance). There is no way to experience absolute infinity, for example. We can define it, but to invoke it as an object/property without constructing it, one would have to postulate or imagine some kind of realm in which it exists merely because it was definable.

One can contrast this to constructive mathematics, in which one must use an idealist or dualist lens (probably the latter, due to them designating the aid of computers performing calculations (necessarily) outside our experience as valid).

I would disagree. In order to do classical mathematics or certain types of logic, one has to view it through the lens of Platonic forms (or some other non-mental, non-physical substance). There is no way to experience absolute infinity, for example. We can define it, but to invoke it as an object/property without constructing it, one would have to postulate or imagine some kind of realm in which it exists merely because it was definable. — Ø implies everything

I think you and I are using the term "idealism" with different meanings. When I say "idealism" I mean philosophies similar to Plato's. From Wikipedia - "In its most basic fundamentals, platonism affirms the existence of abstract objects, which are asserted to exist in a third realm distinct from both the sensible external world and from the internal world of consciousness, and is the opposite of nominalism."

Am I using the word wrong? Anyway, whatever language differences we are having, I think you and I agree that seeing the world through Platonist glasses, as described in Wikipedia, would be useful for mathematicians.

When I say "idealism" I mean philosophies similar to Plato's — T Clark

That is not the typical definition, no. Though, I feel like I have a vague memory of it being used in that way; in any case, I do believe there is a tradition of using terms Forms and Ideas interchangeably.

However, the typical definition of ontological idealism is that it is the view that all of reality consists solely of the mental. On this point, Platonism is explicitly not; take what I say with a grain of salt, but I think Platonism is a substance pluralism, in that it claims there is a mental substance, a physical substance and an abstract substance (the latter consisting of Plato's forms).

Note also that epistemological idealism is the view that we only know (of) the mental.

I find your qualitative/quantitative typology to be a bit imprecise. For example, idealism is often a priority monism (one basic concretum, which is God), but typically not an existence monism (one concretum, i.e. it has no proper parts). Perhaps I am wrong on that, but either way, I'm sure you see the importance in differentiating between priority and existence monism.

That is fair: I should have included that distinction in my synopsis.

I am familiar with the argument from parsimony, and although I find myself somewhat agreeing with it from a pragmatic point of view, I am in the enterprise of creating a theory of absolute certainty. Thus, making ontological assumptions based on pragmatic considerations is not really what I am about.

In that case, I think we are both in the same boat then: the only valid ontological position in philosophy of mind is in principle agnosticism.

I do think, however, that epistemological idealism is obtainable by the argument from parsimony.

Furthermore, the argument from parsimony is not an argument for how it is impossible for the mental and non-mental to interact; instead, it is an argument for how it is unlikely and/or how it is most economical to assume they do not, one the basis of the how it is uneconomical to posit/unlikely that the non-mental exists.

Just to clarify, I wasn’t trying to claim that the argument from parsimony is related to the problem of interaction: you are right that they are two separate things.

Bob

In that case, I think we are both in the same boat then: the only valid ontological position in philosophy of mind is in principle agnosticism. — Bob Ross

Well, I am in that boat, but only reluctantly so. I have been able to derive things from the empty set of assumptions, and as such, I might be able to derive ontological idealism. I think it might be possible via realizing restrictions on causality.

I do think, however, that epistemological idealism is obtainable by the argument from parsimony. — Bob Ross

I think epistemological idealism is obtainable through quite simple logic. All knowledge is directly derived from the mental (by definition of the mental), and in order to know that we can know of the non-mental is to know that there is a completely reliable mapping between the mental and non-mental. However, any such knowledge would be mediated by the mental. How can we know of a mapping if we do not have access to both the domain and its image?

When one introspects upon their experience (which is consciousness), they will begin to realize that every object within their experience is wholly reducible to a collection of sensations. — Bob Ross

How about judgement and reason? Is a rational judgement, like a syllogism, reducible to sensations?

However, the typical definition of ontological idealism is that it is the view that all of reality consists solely of the mental. — Ø implies everything

I think there's an unstated problem in this description, which is how to grasp 'the mental' as an object of cognition. I think this is what panpsychism does: it attempts to show that the capacity for experience is something which even the most primitive fundamental particles, such as electrons, possess, and is in that sense, an objectively existent attribute. Then this latent capacity for experience is said to account for the much more sophisticated capacities found in animals and humans.

However, panpsychism is criticized for the combination problem, i.e. what is it that enables all these micro-experiential entities to be combined into the unified whole that presents itself in experience. Many philosophers regard that as a defeater for the Strawson/Goff style of panpsychism.

Okay. No arguments come to mind (as I'm not an "idealist" of any flavor) except, of course, Bishop Berlekey's (see Kant's "Refutation ...")

There aren't any good ontological arguments. In fact all Major General Advances in Philosophy are against all idealistic principles.
i.e.
Naturalism (in the domain of metaphysics) vs. Supernaturalism
Evidentialism (in the domain of epistemology) vs. mysticism, authoritarianism, dogmatism, a priori facts, faith.
Consequentialism(in the domain of ethics) vs. authoritarianism / absolutism
Aesthetic Relativism(In the domain of aesthetics) vs. cosmic aesthetics / aesthetics as morality.

Major Specific Advances also ignore idealism all together.
• Set Theory
• Symbolic Logic
• Reduction of Mathematics to Axioms & Logic (Russell)
• Transfinite Mathematics (Cantor)
• Game Theory
• Gödel’s Incompleteness Theorems / Dan Willard's Solutions
• Modal Logic
• Bayesian Epistemology
So there is really no place for idealism in Philosophy except from Chronicling.
Idealism doesn't assist our Philosophical goals (the production of wise claims about our world and the expansion of our understanding).

I suppose one formulation of idealism would be: there are only ideas and nothing else.

So, all there is are ideas, and ideas come from minds. If this is the argument, then we cannot say that there is non-mental stuff. The interaction problem does not arise.

One problem that arises out of such a formulation is pointed out by Galen Strawson, I think correctly. If there are only ideas, then the person who has the ideas, is also an idea.

But this is a problem, because an idea is (or should be) an idea for someone, a subject. But if the subject is an idea, then who is it that has the idea? Another idea? We could say a mind has ideas. But then the mind too would be an idea. That's not too coherent.

But, that's a very vulgar and general formulation of idealism, there are many others, which are quite sensible.

I think there's an unstated problem in this description, which is how to grasp 'the mental' as an object of cognition. — Wayfarer

Well, I have many questions regarding how to grasp anything as an object of cognition, but I do not think that the category of the mental poses a lot more difficulty than any other concepts. There is some added difficulty due to its primitiveness however; it is only understood through pointing to experience, and the successful reception of that requires a non-verbal leap in the mind of the receiver. That said, all concepts derive from primitives and thus inherit this difficulty; however, the difficulty is less visible at these higher levels of conceptual aggregation, and there are also likely more sources of meaning rushing in to ground the concepts; though, that amplifies another issue, the issue of signifiers having distinct groundings between speaker and recipient.

You point to a tough challenge for idealism.

In some ontologies based on objective idealism, all thinkable, perceivable and feelable objects exist regardless of whether they are the objects of any finite subject's consciousness. Perhaps these object's intrinsic natures also exist, despite those natures being incomprehensible to said finite subjects; for example, absolute infinity is a thought/concept whose extrinsic nature is thinkable to finite subjects. For proof, see this definition; absolute infinity is a quantity of which no number could be larger. Due to its definability, it has an extrinsic nature. In an ontology based on objective idealism, there could be a "place" for its intrinsic nature to exist as well, despite perhaps our fundamental incapacity to mentally access that nature.

This brings me to subjects . In an objectively idealist reality, the intrinsic nature of subjects could, like absolute infinity, also have a place in this objectively idealist reality; it is simply that this place is not (necessarily) the theater of our experiences. Perhaps it is capable of entering the theater temporarily, though, through deep introspection/meditation. Can you bring awareness to your awareness itself? Can a subject be its own object? Even if it can, we know from experience that it is not so at all times. Thus, we need something more to explain our own existence.

Another solution is to not define the mental as the contents of mentation, but rather, the space/medium of mentation. Thus, with this definition, idealism is not postulating the sole existence of experience, but rather, only the existence of experiencer(s). However, for this to then be idealism, experience would need to be derivative from experiencer; if not, then one would not be dealing with a monism, and thus, it would not be idealism. Bernando Kastrup conceptualizes this derivativity as experience being to experiencer what waves are to water.

The last solution is to simply reject the premise that experience necessitates an experiencer. What have we to support this notion, really? If we can envision a lifeless physicalist reality, why not a lifeless idealist reality? What if it is all an illusion; what if the self is just a construct of thoughts that belong to no-one, but that insist on belonging to someone? Can I not write on a paper, "Hey, I (this paper) am alive!". Perhaps an idealist reality can have objects that falsely proclaim the existence of a self. One can summarize this view with the following:

Cogito, ergo sum? No: Cogitatio est, ergo cogitatio est.

It’s actually a very good question. Hobbes I think it was that drew a very good analogy about what you’re taking about.

An example of the mind mater duality is hitting your big toe…the signal travelled to the brain to inform of pain and avoid pain in future.

Useful to brain and body.

It’s an evolutionary trait other wise we’d be breaking hurting our body without this

Cogito, ergo sum? No: Cogitatio est, ergo cogitatio est. — Ø implies everything

:up:

It seems to me that 'ontological idealism' entails absolute (i.e. "divine") solipsism, which – though conceptually unparsimonious – is, in practice, indistinguishable from ontological naturalism (e.g. epicurean atomism or spinozist realism). I think the arguments for the latter are cogent and existential in ways the former are not.

Objective idealism, if mind is considered necessary for the mental to exist, does entail a mind at large, as Bernando Kastrup puts it. Adding a few quite sensible assumptions to objective idealism, we do arrive back at science. I assume that's what you tried to say by ontological idealism being in practice indistinguishable from naturalism. However, ontological is a bit too general for that.

I wonder, why do you find idealism conceptually unparsimonious, and why do you find naturalism more cogent?

Cogito, ergo sum? No: Cogitare, ergo cogitare.
— Ø implies everything
:up: — 180 Proof

Noticed that my Latin grammar was wrong, so I've edited the quoted text. I hope the message you received has not been affected.

Ontological naturalism, which I referred to, is the speculative generalization of "naturalism".

In some ontologies based on objective idealism, all thinkable, perceivable and feelable objects exist regardless of whether they are the objects of any finite subject's consciousness. — Ø implies everything

This sounds like a complication. An object is an idea regardless of the subjects experience? Why postulate an object which can (perhaps) never be encountered by a subject and also claim its ontological status beforehand?

There could be some phenomenon that cannot be encountered by our kind of experience.

In an ontology based on objective idealism, there could be a "place" for its intrinsic nature to exist as well, despite perhaps our fundamental incapacity to mentally access that nature. — Ø implies everything

I think that's fair.

Can you bring awareness to your awareness itself? Can a subject be its own object? Even if it can, we know from experience that it is not so at all times. — Ø implies everything

Correct. Schopenhauer addresses this point rather well, about us being both subject and object. And yes, our self-consciousness fluctuates.

However, for this to then be idealism, experience would need to be derivative from experience; if not, then one would not be dealing with a monism, and thus, it would not be idealism. Bernando Kastrup conceptualizes this derivativity as experience being to experiencer what waves are to water. — Ø implies everything

Why can't idealism be monist? One could speak of the different aspects of the mental.

Kastrup uses this analogy, and it has some force. Sure, there is only water, but the activity of waves is an attribute or property of the water: water can be wavey, given certain circumstances.

In other circumstances, water can't be wavy, for instance if it is forzen. So while we are still speaking of water, we should consider the epistemic conditions that allow us to label something as wavy, or frozen. Which takes us somewhat beyond "just" water.

What if it is all an illusion; what if the self is just a construct of thoughts that belong to no-one, but that insist on belonging to someone? Can I not write on a paper, "Hey, I (this paper) am alive!". Perhaps an idealist reality can have objects that falsely proclaim the existence of a self. — Ø implies everything

There is a sense in which the self is an illusion, or rather, a fiction, in Hume's phrase. But beyond our own conditions of having selves, to extend that to objects and attribute to them this aspect of "self", is not warranted, regardless of ones ontology.

How about judgement and reason? Is a rational judgement, like a syllogism, reducible to sensations?

I hold that awareness, will, and reason are non-physical and aren't really objects--as all three are dependent on the will or is the will itself. What I was trying to convey was that all objects (i.e., physical stuff) is reducible to sensations themselves and there is no need to posit conceptually some kind of sensation-free object.

Bob