Jackwhitlocke_005 wrote:1. We experience all things through the mind
2.Other people are experienced only through the mind
3.Other being cannot be known to exist outside the mind

Any criticism/ counter arguments are welcome. Just please don't respond with "If you are a solipsist then you don't believe I exist, so why are you asking this?" I am not a solipsist. This is simply a discussion of an argument for solipsism.

Solipsism is the philosophical idea that only one's own mind is sure to exist.

Solipsism is an incoherent theory.

"1. We experience all things through the mind "
The above presupposed 'philosophical realism'.
Philosophical realism asserts that reality is absolutely independent of mind.
Since reality (all things) are independent of mind, the only means of knowing the 'real' thing is through the mind.
This knowing is based on the correspondence theory of truth.

But philosophical realism is not tenable.
Rather reality is always inter-dependent with many minds. (many = collective minds, not just the individual mind). Note Kant's theory.

The collective* mind implied one knows other minds exist, not just one's own mind.
Therefore solipsism is incoherent.

*For example, when one is aware of teamwork and team results, each team-members are aware there are other team members.

In anycase, here is another view why solipsism is incoherent.
http://www.iep.utm.edu/solipsis/#H7

ciceronianus wrote:

Jackwhitlocke_005 wrote:So, if you claim there is a "world outside yourself" you better have good reasons for believing so. The thing is, no one has been able to do it.

God's teeth. You make my point (regarding silliness) for me, I think. Define "good reasons" for believing there is a world outside myself. I assume these cannot include the fact that you are communicating with me.

I think you are conflating the common sense/ordinary/conventional perspective with the philosophical perspective.

In the conventional perspective, the default is the existence of an independent external world and this has survival value and occupy human consciousness most of the time. But this conventional perspective of the senses, empirical evidences, reason (basic and pure) has limitations. This perspective is analogical to say, the Newtonian perspective which has limitations when dealing with relativity or QM. Due to its limitations, philosophers had ventured to explore beyond the conventional perspective, i.e. the philosophical perspective.

From the philosophical perspective, one has to discard the independent external world default of the ordinary perspective and starts afresh. This is why Kant asked for proof of the external world. So far, no one has provided convincing proofs and imo, there will never be any from the philosophical perspective.

The philosophical perspective that holds the existence of an independent external world is 'philosophical realism', objectivism, and physicalism. Note philosophers like Putnam (has since given this up) and many other analytics hold this independent external world view within the philosophical perspective.

-- Updated Mon May 07, 2012 12:09 am to add the following --

Scott wrote:In regards to solipsism specifically, if one wants to argue for that then one needs to define mind.

"1. We experience all things through the mind"

Point 1 above assumed the mind to be a closed container, e.g. in wiki,

In popular usage 'mind' is frequently synonymous with thought: the private conversation with ourselves that we carry on "inside our heads." Thus we "make up our minds," "change our minds" or are "of two minds" about something. One of the key attributes of the mind in this sense is that it is a private sphere to which no one but the owner has access. No one else can "know our mind." They can only interpret what we consciously or unconsciously communicate.

However, from the philosophical perspective, note,

The concept of mind is understood in many different ways by many different traditions, ranging from panpsychism and animism to traditional and organized religious views, as well as secular and materialist philosophies.

Theories of mind and its function are numerous. Earliest recorded speculations are from the likes of Zoroaster, the Buddha, Plato, Aristotle, and other ancient Greek, Indian and, later, Islamic and medieval European philosophers. Pre-modern understandings of the mind, such as the neoplatonic "nous" saw it as an aspect of the soul, in the sense of being both divine and immortal, linking human thinking with the unchanging ordering principle of the cosmos itself.

[/quote]In the above case, the concept of 'solipsism' is extended from a conflation of common sense with the philosophical perspective with limited critical thinking.

At present, 'mind' in the common and philosophical perspective is merely a very loose term and 'what is consciousness' is still a 'hard' problem. Since 'mind' and 'consciousness' are loose terms, 'solipsism' which relies on them should be a looser term, or better still, put in the 'recycle bin'.

Prismatic wrote:There is no logical refutation of solipsism—it's watertight. Naturally that does not prove it just as the lack of disproof of the existence of gods does not establish their existence.
It seems that infants are solipsistic and must learn through experience that there are (or to continue the solipsistic viewpoint, there appear to be) other minds with different thoughts. Solipsism doesn't fit well with the notion that as the human character matures it becomes less self-centered and grows more concerned with other people and otherness in general. Some never get beyond their own concerns despite the teachings of religion, but most people grow to have concern for others not like themselves and that is one measure of maturity.

I don't think your 'baby' example is applicable, note wiki's.

Solipsism is the philosophical idea that only one's own mind is sure to exist.

Infants do not philosophize consciously and intellectually.

Prismatic wrote:

Spectrum wrote:

Prismatic wrote:There is no logical refutation of solipsism—it's watertight. Naturally that does not prove it just as the lack of disproof of the existence of gods does not establish their existence.
It seems that infants are solipsistic and must learn through experience that there are (or to continue the solipsistic viewpoint, there appear to be) other minds with different thoughts. Solipsism doesn't fit well with the notion that as the human character matures it becomes less self-centered and grows more concerned with other people and otherness in general. Some never get beyond their own concerns despite the teachings of religion, but most people grow to have concern for others not like themselves and that is one measure of maturity.

I don't think your 'baby' example is applicable, note wiki's.

Solipsism is the philosophical idea that only one's own mind is sure to exist.

Infants do not philosophize consciously and intellectually.

I mentioned the infant mind not as any logical refutation of solipsism or even as evidence against it—that does not seem possible—but because it shows that a major intellectual advance for children occurs when they stop being solipsistic and recognize the existence of other minds. Human ability to recognize other minds, for which direct experience is lacking, appears to be unique to the human species and is one reason complex social interactions are possible. It is the best explanation of human behavior and has evolutionary value.

Rarely do we have proof beyond any possible doubt and most of our theories of how things work are simply ones that explain a great deal and predict outcomes correctly. We can adapt these to fit new circumstances and if they prove deficient in comparison with other views, we can simply abandon them.

OK, I think you are refering to "Theory of Mind" i.e.

Theory of mind (TOM) is the ability to attribute mental states—beliefs, intents, desires, pretending, knowledge, etc.—to oneself and others and to understand that others have beliefs, desires and intentions that are different from one's own.[1] Though there are philosophical approaches to issues raised in such discussions, the theory of mind as such is distinct from the philosophy of mind.

TOM is developed in children after a certain age, and deficit in TOM is due to "mind-blindness", autism, schizo and other pychological issues.

I don't think the philosophical issue of 'solipsism' is directly related to 'Theory of Mind'. 'Solipsism' is a hypothesis supported by its own specific philosophical arguments which imo, is wrongly extrapolated from the wrong interpretations of fundamental idealism, i.e. reality is all mental stuffs.

TOM with reference to child development is with reference to a very specific definitions of mind and belief. When a baby cry for attention (instinctive) from the mother, it is implied the baby is connecting with another 'mind'. The baby instintively know there is another 'mind' other than its own 'mind', if we define mind as the works of the physical brain.

-- Updated Tue May 08, 2012 2:26 am to add the following --

ciceronianus wrote:

Spectrum wrote:I think you are conflating the common sense/ordinary/conventional perspective with the philosophical perspective.

In the conventional perspective, the default is the existence of an independent external world and this has survival value and occupy human consciousness most of the time. But this conventional perspective of the senses, empirical evidences, reason (basic and pure) has limitations. This perspective is analogical to say, the Newtonian perspective which has limitations when dealing with relativity or QM. Due to its limitations, philosophers had ventured to explore beyond the conventional perspective, i.e. the philosophical perspective.

From the philosophical perspective, one has to discard the independent external world default of the ordinary perspective and starts afresh. This is why Kant asked for proof of the external world. So far, no one has provided convincing proofs and imo, there will never be any from the philosophical perspective.

I know of nothing that requires a philosopher to discard an independent external world, and I rather doubt many philosophers do so. There are those who may believe that what we know of it is the result of our interaction with it, which I have always felt is merely to assert that we are human beings and experience it as human beings do (a rather uninteresting assertion, I think), but those who actually think there is nothing but themselves are, I hope, few and far between. I tend to think reference to an "external" world is somewhat sloppy; we are as much a part of the world as anything else.

As I had mentioned, the view of an independent external world is a default of common sense, ordinary, conventional and non-QM physics. No ordinary (except the schizo or psychotic) person or philosophers would discard this default view. The perspective that we are a part of everything else would be more refined than common sense and thus more appropriately a philosophical perspective.

Philosophers may amuse themselves and others by doubting the existence of "the external world" for purposes of an exercise, of course, in the faux manner of Descartes, or befuddle some novice by asking him/her to "prove" there is an external world. But I think one should have a good reason to doubt before doubting. I know of no good reason to doubt, for example, that I'm using a computer at this moment.

Actually many philosophers do not doubts the "external world". What they are actually doing is countering those who are dogmatic on the independent external world theory. "Countering dogmatism" is a more realistic term than 'doubting' which is a very misleading word

When they counter the independent external world theory from a philosophical perspective, they are not discarding the common sense perspective. They are just changing hat for the moment or shifting perspective relevant to the circumstances. Note the Necker Cube Demo, they are toggling between the two cubes rather than merely seeing one but not the other cube at all.

There are lots of usefulness from the concept of an independent external world, but it also has its limitation and baggages when taken to the extreme.

One of this extreme is an independent external world created by an independent God. I am sure you are aware how bad (despite some usefulness) this associated baggage has cost humanity and will be a potential hindrance to the progress of mankind in the future.
The other is Scientism. While Science is very useful for mankind, it has its negative side, i.e. Scientism.

An independent external world deliberately separate (by theory) the subject from objective reality, when as you are aware, in reality, the subject is part and parcel of reality as a whole. In the independent external world perspective, the subject has no interrelation with reality and thus is at the mercy of the external world.
On the otherhand, a subject interdependent reality recognize that the subject (s) [individually and collectively] has a role in the actualization of reality. Note Neuro-cognitive Science is recognizing this interdependent role.

Perhap there is some sort of cognitive biasness that do not enable you to recognize any limitations in the perspective of an independent external world. If you can break those glasses, there are tons* of reason why a dogmatic philosophical (not common sense) perspective of an independent external world is not tenable or is limited. I have a list of 70+ of such reason and trying to accumulate at least 101 reasons for the limitation of a philosophical independent external world.

ciceronianus wrote:

Spectrum wrote:The perspective that we are a part of everything else would be more refined than common sense and thus more appropriately a philosophical perspective.

I disagree. I think the perspective that we are not a part of everything else is peculiarly (in more than one sense) philosophical, and can be attributed to the dualism promulgated by philosophers such as Descartes. The mind-body distinction is one indulged in by philosophers as well.

I had mentioned the default view of common sense as taken for granted is an independent external world. Philosophers used to call this view, the 'vulgar' * view. [*archaic: common view]. Wonder why you insist that common view is philosophical.
Descartes dualism is after some very serious philosophical deliberation and of course is a much more deeper than the common sense external world.

It does take some reflection and philosophical thinking to realize that 'no man is an island by itself'. When the majority of humans do so, there will be a lesser threat to our Earth's environment that everyone share and live in.

I think there is a tendency among some philosophers to accord greater significance to our interaction with the rest of the world and its result than is warranted. This may be the result of what I think is a kind of poetic license on their part. When philosophers (or others) speak of "creating" or "shaping" reality, or that the world is not "independent" it seems they purport to assert that something more is involved than that interaction, which I view as what takes place as a result of the undeniable and unremarkable fact that we are humans and part of the universe.
Just what more they are asserting I can't understand. I assume they are not claiming that I'm creating my desk while sitting at it in any normal sense, or if they are I think they're claim is unsupported. As to QM, I have no idea where it is taking us, but I don't think that what may be the case on the quantum level means there is something wrong with claims and expectations related to what is not.

Obviously no philosophers had insisted that you or anyone else is "creating" the desk one is presently writing on. It is very wrong to think they do. What philosophers view differently from ordinary people is something else.

ciceronianus wrote:Just what more they are asserting I can't understand

Note this from William James.

James wrote:THE progress of society is due to the fact that individuals vary from the human average in all sorts of directions, and that the originality is often so attractive or useful that they are recognized by their tribe as leaders, and become objects of envy or admiration, and setters of new ideals.

Among the variations, every generation of men produces some individuals exceptionally preoccupied with theory. Such men find matter for puzzle and astonishment where no one else does. Their imagination invents explanations and combines them. They store up the learning of their time, utter prophecies and warnings, and are regarded as sages.
Philosophy, etymologically meaning the love of wisdom, is the work of this class of minds, regarded with an indulgent relish, if not with admiration, even by those who do not understand them or believe much in the truth which they proclaim.

Philosophy, beginning in wonder, as Plato and Aristotle said, is able to fancy everything different from what it is.
It sees the familiar as if it were strange, and the strange as if it were familiar. It can take things up and lay them down again. Its mind is full of air that plays round every subject. It rouses us from our native dogmatic slumber and breaks up our caked prejudices.

Note this from Russell;

Russell wrote:The man who has no tincture of philosophy goes through life imprisoned in the prejudices derived from common sense, from the habitual beliefs of his age or his nation, and from convictions which have grown up in his mind without the co-operation or consent of his deliberate reason.
To such a man the world tends to become definite, finite, obvious; common objects rouse no questions, and unfamiliar possibilities are contemptuously rejected.
As soon as we begin to philosophize, on the contrary, we find, as we saw in our opening chapters, that even the most everyday things lead to problems to which only very incomplete answers can be given.
Philosophy, though unable to tell us with certainty what is the true answer to the doubts which it raises, is able to suggest many possibilities which enlarge our thoughts and free them from the tyranny of custom. Thus, while diminishing our feeling of certainty as to what things are, it greatly increases our knowledge as to what they may be; it removes the somewhat arrogant dogmatism of those who have never travelled into the region of liberating doubt, and it keeps alive our sense of wonder by showing familiar things in an unfamiliar aspect.

I think why you cannot understand is because you had not philosophize deep enough. The ability to wonder deeper has limitations for some due to their nature and inclinations.

Note this Necker Cube,


Some people just do not has the ability to see two cubes in this picture. They can only see one. Similarly, there are many deeper perspectives beyond the external world that the normal human being take for granted. Philosophizing the perspective of a subject-interdependent reality is one sophisticated perspective many cannot and will not see no matter how one explain it to them. This interdependent perspective is not for intellectual fun, it has utilities for life in its finer perspectives. Btw, I do not intend to convince you of such a perspective, I am just expressing my POV on it.

ciceronianus wrote:

Spectrum wrote: What philosophers view differently from ordinary people is something else.

It seems that at least since Plato, there have been philosophers who delight in distinguishing themselves from "ordinary people" and their concerns. I agree with Dewey that there has been a tendency in philosophy to disdain the "problems of men" and focus instead on the "problems" of philosophy, and that this has been to the detriment of philosophy and humanity. I also agree with Dewey and with pragmatism generally that the only true problems are problems which create real doubt and admit of resolution, and that we only think reflectively and critically when we encounter problems. Philosophers may be the the only people who take pride in the fact that they address questions which by their nature cannot be answered.

Again, this may have value as an exercise, and in promoting open-mindedness and creative thinking. But I think philosophy can do more than that, and question the value of doubting when there is no reason to do so.

Personally I believe philosophy should deal with both the speculative (the awe and wonder, not focus on doubting) and the practical down to earth experiences.

It is not 'nature cannot be answered', rather there it cannot be answered with absolute certainty. I think Dewey would agree with this.

From what I read of Dewey's 'Reconstruction of Philosophy', what he is against is the dogmatism and arrogance in Western Philosophy, e.g.

Even at the best, it has tended to produce an overdeveloped attachment to system for its own sake, and an over-pretentious claim to certainty.
They have insisted that they were more scientific than the sciences that, indeed, philosophy was necessary because after all the special sciences fail in attaining final and complete truth.

Philosophy has arrogated to itself the office of demonstrating the existence of a transcendent, absolute or inner reality and of revealing to man the nature and features of this ultimate and higher reality.
It has therefore claimed that it was in possession of a higher organ of knowledge than is employed by positive science and ordinary practical experience, and that it is marked by a superior dignity and importance a claim which is undeniable if philosophy leads man to proof and intuition of a Reality beyond that open to day-by-day life and the special sciences.

It would appear from the above he was condemning the academics, logical positivists and the analytics.

In anycase, I think the analytics, the non-analytics (note Kant as pointed out by Prismatic) had contributed to humanity in various ways. What is negative with these philosophies is when anyone of them hold arrogant and dogmatic view of their theories.

Solipsism is incoherent and realistically should be a non-issue.
It is only a pejorative term raised by the dogmatic realist who insist there is an absolute independent external world.

Although the number of individuals sincerely espousing solipsism has been small, it is not uncommon for one philosopher [imo, the dogmatic realist] to accuse another's arguments of entailing solipsism as an unwanted consequence,..

Thus anyone who acknowledge s/he is a solipsist (I have not come across any philosopher?) and tries to argue for it, has already lost the argument to the dogmatic realist from the start.

As such, if anyone who wants to argue for any non-realist theory, they should avoid, ignore, and reject the solipsism label to be attached to their theory. Just go ahead an argue why there is or there is no external world and the likes. The same goes for the loose term 'idealism'.

H M wrote:

Belinda wrote:HM wrote:

Berkeley wasn't sceptical of the external world; properly understood, the latter just is the content of extrospection, co-confirmed with others.

For Berkeley esse is percipi ; to be is to be perceived. The implication is that being depends on perception. Who perceives? Whose ideas prevail? The human and God perceive, but God perceives infinitely and the human finitely.Therefore Berkeley is sceptical about the reality of the external world.

This is the very sleight of hand I was referring to. Metaphysical realists (or materialists in this instance) hijacked the term "external world" and tried to cozen us into believing it has always referred to their general substance and/or transcendent version of bodies and space. By gosh, there was no "external world" until materialists came along with their product of reflective thought! Let's replace the empirical environment plainly seen and felt as outside our equally plainly seen and felt bodies with an abstract realm and substance that is hidden, so that we can then run about like idiotic chickens with our heads cut-off and proclaim we have no proof of an external world. "Proof" rather than empirical evidence now entering the picture because the kind of external world they've foisted upon us was a product of reasoning, ergo it seems to now require the concoction of an invincible argument to verify it.

Here is Berkeley's view on the external world, re A Treatise Concerning the Principles of Human Knowledge [PHK],

35. I do not argue against the existence of any one thing that we can apprehend either by sense or reflexion. That the things I see with my eyes and touch with my hands do exist, really exist, I make not the least question.
The only thing whose existence we deny is that which philosophers call Matter or corporeal substance.

"Matter" in this philosophical perspective is taken to be an inert senseless substance, unthinking and independent of the human mind.
Locke and Berkeley had proven that "matter" has mind dependent primary and secondary qualities, thus there is a contradiction if anyone were to claim "matter" is independent of mind.

Thus Berkeley claimed in PHK,

3. For as to what is said of the absolute existence of unthinking things without any relation to their being perceived, that seems perfectly unintelligible.
Their esse is percepi, nor is it possible they should have any existence out of the minds or thinking things which perceive them.

IMO, despite 3 above, from his Principles of Human Knowledge, the essence of Berkeley's emphasis was more on secondary and primary qualities rather than on 'esse is percepi'. The onus is on the philosophical materialists to provide proofs of their claim that their "matter" exist.

Berkeley main counter against materialism was based on Locke's secondary qualities and his own arguments for the existence of mind-dependent primary qualities. IMO, this two arguments are sufficient to put a negative limit on philosophical materialism.
His additional phrase of 'esse is percepi', and terms like ideas, 'spirit', god, etc. are secondary to the issue. "Percepi-Perception", "ideas" are very complex terms and should not be taken on from the common perspective.
However, Berkeley's esse is percipi had been misinterpreted from the common perspective by many to be his main theory and is forced it into solipsism (in a pejorative sense) to make it look stupid.

If 'solipsism' is taken to be 'believing only one's mind exist', then it is the philosophical materialists who are solipsistic. When a philosophical materialist or realist believes that 'matter' and the external world is absolutely independent of their mind, then, the only mind they can possibly and REALLY 'know' of, would only be their mind via the cogito, thus fitting the definition of 'solipsism'.

Belinda wrote:I am afraid that I do not see what HM and Spectrum see , despite their careful explanations. Berkeleyan idealism summed up as esse is percipi seems perfectly good to me, as long as God grants to people his divine reason which confers rationality so that order is imposed upon what would otherwise be isolated sets of ideas at variance with each other. I am not sure how my explanation of Berkeley is any different from pre-established harmony.

My point: from my reading of Berkeley, it would be preferable to ignore his maxim 'esse is percipi' which can be easily misinterpreted by others. Berkeley's intent was to prove God exists, i.e. the gist of his proof in simple form,

1. Objects that exist are comprised of mind-dependent primary and secondary qualities.
2. The above are represented by ideas in mind [thinking].
3. An unthinking object is a contradiction, thus 'esse is percipi', and,
4. If no one to percipi, then God is perceiving.
5. God is perceiver of the whole of nature and universe.
6. Only an omnipresent God can perceive all,
7. therefore, God exists.

I had not presented Berkeley argument fully and what I had left-out premises are in his book. Nevertheless, what I had left out is not critical in this situation.
IMO, the only point that is useful from Berkeley is only point 1. We can forget about points 2 to 7 including 'esse is percipi'. These point were introduced by Berkeley to justify the existence of God.

Berkeley's proof in 1 is sufficient to limit philosophical materialism, and there is no need to use 'esse is percipi' which is leading to his proof for God which non-theists are not interested at all.

From point 1 of Berkeley above (ignoring 2 -7), we should then continue with Kant's transcendental idealism. Kant's theory is not thorough, we need to supplement it with those of Hegel, Nietzsche, Heidegger and others.

Belinda wrote:Thanks Spectrum, I understand that. But I object that your points 2 to 7 are needed to render point 1 feasible. True, point 1 is the backbone of the case for idealism. However if point 1 stands alone we either have God or solipsism exclusively as maker of order. Berkeley chooses God as the universal perceiver or order maker, probably remembering the Spirit moving over the waters in Genesis 1. Contrasting the Berkeleyan vision with that of Spinoza who puts nature-necessity in place of the self or the transcendent God it's easy to see why the RCC disapproved of Spinoza.

Berkeley used 1 and moved on to prove his version of God. It not necessary to rely on 2 to 7 to render point 1 feasible.
As I had stated, one can rely on 1 and use Kant to proceed further to understand reality in a more refined perspective.

Spinoza moved to nature and a panentheistic or pantheistic God is definitely more refined than Berkeley's creator God. However as with any God concept, it clashes with Kant's noumenon that limits the existence of God in any form.

Kant in CPR wrote:"If by 'noumenon' we mean a thing so far as it is not an object of our sensible intuition, and so abstract from our mode of intuiting it, this is a noumenon in the negative sense of the term".[20]

As we moved on, one should get rid of the concept of 'noumenon' into 'emptiness'.

Belinda wrote:Spectrum wrote:

Spinoza moved to nature and a panentheistic or pantheistic God is definitely more refined than Berkeley's creator God. However as with any God concept, it clashes with Kant's noumenon that limits the existence of God in any form.

Kant in CPR wrote:"If by 'noumenon' we mean a thing so far as it is not an object of our sensible intuition, and so abstract from our mode of intuiting it, this is a noumenon in the negative sense of the term".[20]

As we moved on, one should get rid of the concept of 'noumenon' into 'emptiness'.

Kant follows on with scepticism about the possibility of absolute knowledge, after Hume shot himself in his empiricism foot after his criticism of induction; Kant's view on the noumenous is that what marks the noumenous is what marks the limit of what we can know. But Spinoza has sorted how we can and cannot know things by his 'adequate ideas'. Those are state of the art knowledge including self knowledge and state of the art judgements.Spinozan philosophy, moreover ,implies that solipsism is impossible because within Spinoza's system nature is both material and mental with non-teleological nature as the one and only uncaused event, therefore one all-creating mind is out of the question; if the solipsist Mind were anything it would be intentional.

I see the dichotomy as between God and solipsistic , transcendent Mind on the one side, and immanent nature on the other side.

God in any transcendent form is limited by Kant , and Hume. But Spinoza's God(nature) is not transcendent in the least but is wholly immanent.Thus the RCC cleverly banned Spinoza. Even the Jews could not risk having him around.

I understand Spinoza's view and his God is reducible to an immanent substance or thing within and without. Spinoza's immanent god is definitely not in line with the RCC's personal god which exists and creates solely from without. If the RCC claim omnipresence for their God, then it should rightly be immanent as well. I am aware the RC mystics in contrast to the lay-RCs, accept their God as immanent like that of Spinoza.

There are various constrasting reading of Kant's Critique of Pure Reason.
From my reading of Kant, while the thing-in-itself can be speculated from pure reason, ultimately there is no such 'thing' as a thing-in-itself. As such, a Spinozan-thing-in-itself is an impossibility no matter which way it is conceptualized or actualized.
The above point is from the ultimate perspective in addition to the other valid perspectives, i.e. ordinary, common sense, linguistic, conventional, scientific, etc. which are all valid but conditional.