Hello, I come from the topic that talks about quantum physics and consciousness. I find what is said in the OP very interesting. My position is the following:

I would say that an impossibility of perception is not an impossibility of the perceived object. Think, for example, of a triangle. Think about the Pythagorean theorem which tells us something about a type of triangles. Now let's think about two people who have knowledge about that theorem and both people accept its universal truth. If the perspective adds something extra, this something extra cannot be the same for the two different perceptions and perspectives that each person has. And here comes the question: what does perspective add in each case? Does it add anything that would affect the theorem in its objective sense, to be different in each case?

Well, in both cases it doesn't add anything that we can say is a property of this type of triangle. With this example we can deduce that the objective properties of things, the being of things, is not reducible to subjective experience, whether understood as perspective. A judgment, therefore, if it hopes to be true, must exceed the order of perception and perspective.

That is exactly what I have referred to: the moment in which the scientist and his measuring devices intervene and affect the coherent system. Such a thing supposes an ontological continuity between the scientist, the measuring devices and the system in a state of "coherence". It would not be legitimate to say that perception or having a "mental representation" alters the system. No, the scientist needs measuring devices (physical devices) to be able to "observe" the system. The effects produced by the measurement are caused by a physical cause and not a mental one.

Something that skepticism has always been criticized for is its inability to account for its intention of universality, truth and objectivity in its own statements. Parallel to this impossibility, Kant made his criticism of empiricism, opening the space for an experience of the true that is not reduced to weak connections such as associations, comparisons of impressions and different problems related to inductivism:

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"Empirical judgments, in so far as they have objective validity, are judgments of experience; they, however, in so far as they are only subjectively valid, I call mere judgments of perception. … All of our judgments are at first mere judgments of perception: they are valid merely for us, i.e., for our subject, and only afterwards do we give them a new relation, namely to an object, and we intend that [the judgment] is supposed to be also valid for us at all times and precisely so for everyone else; for, if a judgment agrees with an object, then all judgments about the same object must also agree among one another, and thus the objective validity of the judgment of experience signifies nothing else but its necessary universal validity."

Kant, Prolegomena (4, 298; 51).

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Is there not in all philosophy and science an intention of truth, of objectivity, of universality of discourse? Therefore, isn't the skeptic's doubt a gesture in a certain sense that is anti-philosophical and anti-scientific? Doesn't it necessarily fall into the liar's paradox? Doubting the world would be like cutting the branch on which I am sitting, waiting for the tree to fall and not the branch.

You say:

we are physically intervening...
— JuanZu

But Greene's quote seems to question that, doesn't it? — Wayfarer

If I do not misunderstand what he is referring to, it is that a quantum system has its properties of uncertainty even without the intervention of the scientist's measurement. And what I have referred to is that the loss of that property of uncertainty occurs when the scientist measures with his physical devices.

Both positions are not contradictory. In fact they complement each other. Since I have not said that the quantum properties of a coherent system are an effect of measurement. Instead, I have said that the loss of these properties is an effect of the measure.

When we measure [for our case in the process of wave function collapse] we are not “Becoming aware” of a phenomenon, but rather we are physically intervening in the state of quantum coherence, which causes the collapse of the wave function
— JuanZu

Not according to Brian Greene.

The explanation of uncertainty as arising through the unavoidable disturbance caused by the measurement process has provided physicists with a useful intuitive guide… . However, it can also be misleading. It may give the impression that uncertainty arises only when we lumbering experimenters meddle with things. This is not true. Uncertainty is built into the wave structure of quantum mechanics and exists whether or not we carry out some clumsy measurement.
— Brian Greene, The Fabric of the Cosmos — Wayfarer

Sorry if I misinterpret, but where would he disagree with me?

Since the appearance of subjectivity described as interiority separated from the world, we have called the external world as that which is not subjective, that is not a perception and that it is in its being to exist independently of perception, as an exteriority. I have deduced an external something, which also implies non-perception in its being, and also its being independent of perception, and also its exteriority, taking as a resource the question about objective truths..

Objective truths do in fact depend on an external world, a world that I have defined as a non-perceptual exteriority beyond subjectivity that also encompasses subjectivity. And this includes truths about subjectivity. A statement like "It is true that only my subjectivity exists" is a contradictio in adjecto. And we deduce this from the conditions so that a statement, whatever it may be, can be true. And these conditions imply that a truth to be in effect a truth must exceed the subjective order, just as the truth exceeds the order of opinion [doxa], to take an example.

Your claim here suggests that you think that a statement can only be true if it "corresponds" to something that exists, and so that if a true statement is about something non-physical then it must correspond to some non-physical thing that exists. — Michael

No. I claim that the essence of objective truths cannot be reduced to either perception or subjectivity. If there are truths it is of condition of this excess with respect to subjectivity. A truth can be about something physical, about mathematical, linguistic, sociological, economic objects, etc. But for it to be true it must exceed the order of perception and subjectivity. Even if it is a truth about subjectivity itself I.E “I perceive, therefore I am.”

Do mathematical truths have nothing to do with matter and energy? I agree, that's why I'm not a physicalist.

If the example you have given is a truth, it is only a condition that its meaning is the same, for example, when another person says it; or even if both have already died and it is encrypted in a text. It is something that belongs to the essence of truth, to be valid beyond subjectivity and perception.

Thus, a truth, this time a truth about existence, our existence, if it is a truth, in order to be that, a truth, has the condition of not being reducible to perception and consciousness. If it is not reducible to this, this means that its nature reaches and is situated in the exteriority of the non-perceivable [World, texts, words, other people, etc.].

Those who doubt the existence of the world fall into an ontological version of the liar's paradox.

No. If you are not a Platonist, mathematical objects may depend on or be nothing more than objects emerging from brain processes. And a physicalist will have to demonstrate that. The conclusion you reach is false. But my argument holds. If we are not Platonists we can say that truths depend on a world beyond the perception that guarantees their possibility. We can, if we are not Platonists, say that we are only talking about physical and chemical processes that occur in the brain and that a mathematical truth is based on these processes. Processes that we do not precisely perceive when we think about those truths. The unperceived appears again. As I have said, the important thing is to understand this world as exteriority beyond perception towards non-perception as a condition of possibility of any objective truth, including the truth about our existence.

The argument holds regardless of whether you are a Platonist or not. And I claim that this argument that I have presented is not false. I claim is true, even if I am no longer around to perceive it or be aware of it. Objective truths are founded in a world beyond consciousness and perception. Otherwise we fall into the ontological version of the liar paradox [if we claim that perception exists just because we perceive ourselves].

I am not talking exclusively about material objects. You can, if you want, consider numbers, logic, ideas, theories, etc., as Non-material objects or ideals [or as a kind of materiality that is not reducible to physicalism]. But the important thing is that its existence along with mine cannot be reduced to perception. There is an outside of perception and consciousness that bases our knowledge about things, including, obviously, our existence.

Arguing that the existence of an external world is the best explanation for my existence is different to arguing that objective truths depend on the existence of an external world. I'm arguing against the latter, not the former. I can (and do) accept the former — Michael

They depend on the "external world" as a non-perceptual exteriority where the non-perceived occurs. There is no value that objectivity and truth is worth that does not exceed the order of the perceptual towards the non-perceptual. Something is true even if I am no longer alive to perceive it, be it the truths of physics, mathematics, etc. Thus, if the statement "I perceive therefore I am" will ever be true, it is only on the condition of a non-perceptive world on which being in this or that way is based [since when we say the truth of a thing we say what it is] Isn't this our relationship with the world? Isn't this the relationship of the perceptual with the non-perceptual? But the most important thing is that my existence cannot be excluded from that exteriority since we could not even know that we exist.

Which doesn't require an external world. — Michael

It requires it since there are no better reasons to affirm your existence than the existence of the world.

My existence doesn't depend on the existence of some second thing; it depends only on my existence. — Michael

It depends on your existence being a non-perceptual "property." And being unperceived is, curiously, something that characterizes the "outside world." That is, your existence is in a certain sense already an exteriority.

You are not showing, you are hypothetically assuming that there are truths about the existence of which their truth does not depend on the external world. But those are hypothetical assumptions. Therefore it cannot be admitted as an argument.

What I claim is that any statement you make about your existence presupposes conditions of truth and objectivity. Otherwise you would have to give me an example of a truth about the existence of something that exists only on the basis of your perceiving it. You will not find it, because the meaning of that truth will always be impersonal just as the objective content of "I, Michael, perceive" is equivalent to that of "Michael perceives."

Thus, if the conditions of truth and objectivity are impersonal [because if I say that you perceive I would not be wrong, I am something that you do not perceive] then your existence is a "property" that can only be validated by going beyond the perception. Therefore your existence is no more true or false than that of the world and the things that we also say "exist."

If you assume that only your mind exists, you can no longer ask about the existence of the external world, you have already closed the way to answering that question. You would want to say that "you only know that your mind exists." But this knowledge already presupposes conditions of truth and objectivity. With which we return to my argument.

You seem to be arguing that both (1) and (2) are true:

1. "things external to my perception exist" is true only if things external to my perception exist
2. "I exist" is true only if things external to my perception exist

(1) might be true (even a truism) but (2) is a non sequitur, and the claim that (2) is true because (1) is true is also a non sequitur. — Michael

You are not taking into account the conditions of truth and objectivity. For the statement "This perception exists" to be true, it requires, so to speak, an impersonal and non-subjective space of validation. Which would have been demonstrated in the example of the future statement. Therefore, ontologically, perception is one more thing among other things in the impersonal and non-subjective world. That is to say, we cannot doubt the existence of the "external world" more than our own perception.

What I have stated is precisely that existence can no longer be reduced to perception. That is, the statement "this perception exists" can only be true if existing is not equivalent to being-perceived. In this order of things, perception has no greater ontological value than "the external world."

Mind-independent truths do not depend on the existence of mind-independent things

If the question is about the existence of the "external world" necessarily the truth of the affirmative answer depends on mind-independent things. But the question lies in the conditions of truth and objectivity. These conditions, as stated above, cannot depend on perception. In this sense, if "existing" says something about me then it can only be true on the condition that my existence is also something non-perceptual.

What if we ask the opposite? What are the reasons to believe that I exist?

Before answering the last question, I consider that we must ask ourselves about the conditions for a statement like "I, Jhon, exist" to be true. If we assume that it is true, wouldn't it be equivalent for a future in which I am in fact already dead? That is to say: "I, John, exist" and "John existed" would be equivalent in the future, and if we accept the first statement as true we must necessarily also accept the last statement as true.

What does this mean? That neither perception nor self-awareness can establish the truth conditions for objective discourse. And this means that for the statement "I exist" to be true, the perception of myself is not a sine-qua-non condition of its truth and objectivity. Non-perception would be essential and a sine-qua-non for true and objective discourse.

And is not what we call the "external world" the domain of Non-perception, as what is not me, as the other, even as another subjectivity other than mine? This being said raises the question of the reasons for believing Whether or not the external world exists is a petitio principii – as long as we expect that the answer [whether affirmative, negative or inconclusive] can be true or false.

We give reasons for something to be true or false. And we hope that in a debate those reasons are valid no matter who utters them. If another person presents our reasons that we consider valid, we must necessarily say that they are also valid. Hence the truth about our existence or the existence of the "external world" does not necessarily depend on whether we perceive it or not. And on the contrary, the conditions of truth and objectivity seem to presuppose a world beyond my perception.

Hello everyone. This is my first intervention. This is my position on the matter.

It seems to me that there is a confusion about what "measurement" means. When we measure [for our case in the process of wave function collapse] we are not “Becoming aware” of a phenomenon, but rather we are physically intervening in the state of quantum coherence, which causes the collapse of the wave function. Introducing consciousness as the cause of quantum decoherence or wave function collapse is a very common error in interpretations of quantum physics: Transcategorical Error. This error consists of introducing notions and concepts that in fact do not and cannot operate in scientific practice.

That is why, taking the above into consideration, instead of using the notions of consciousness and the like, which are rather confusing, we should prefer to describe the phenomenon as the moment in which an isolated or closed system opens up for the environment to intervene. . This frees us from believing that the physical world is in a state of permanent decoherence waiting to be "perceived" so that it acquires the classical properties of physics. In a certain sense it is like saying that the universe measures itself, but this measurement is nothing more than the moment in which the environment intervenes in a closed and coherent system.

To summarize: The objects of study in physics must maintain ontological continuity in such a way that they can be causally-related to each other.