Right, but it's important because it means that our thoughts about the world can't be entirely different from the world, on a realist account. — Marchesk

This doesn't follow. That an ideal theory is dependent on a mind-independent world is not necessarily that an ideal theory accurately describes it. If we're brains-in-a-vat then a theory "which meets all observational data and satisfies every theoretical constraint" might fail to say anything about the world outside the vat (which, according to realism, would be the real world).

If we're brains-in-a-vat — Michael

Assuming we could be brains in a vat. I have my doubts.

If we're brains-in-a-vat then a theory "which meets all observational data and satisfies every theoretical constraint" might fail to say anything about the world outside the vat (which, according to realism, would be the real world). — Michael

Let's say that BIVs are possible. What could an ideal theory say about the world outside the vat? Well, it could say a lot, actually. Consider that the brain in a vat is like the brain in appearance fed to that brain. Which means that neuroscience, chemistry and physics are all similar. Otherwise, you don't have an envatted brain, since the notion depends on the kinds of brains the BIV has in experience, which all depend on physics, chemistry, etc being a certain way.

Then replace "brain" with "[whatever in the real world gives rise to conscious experience]". It could be that whatever is in the vat is nothing like the brain as we understand it and that whatever this thing is in is nothing like a vat as we understand it.

It could be that whatever is in the vat is nothing like the brain as we understand it and that whatever this thing is in is nothing like a vat as we understand it. — Michael

In which case I would just deny the thought experiment as being incoherent, since it can't even say what being envatted means. That coincides nicely with the OP. If mind is dependent on mind-independent reality, then you can't have an arrangement entirely outside our understanding giving rise to our understanding.

Which also means that I deny the possibility of Kant's noumena - the thing in itself of which we cannot say anything about.

If mind is dependent on mind-independent reality, then you can't have an arrangement entirely outside our understanding giving rise to our understanding. — Marchesk

That doesn't follow. That A depends on B is not that an understanding of A gives us an understanding of B. The appearance of Dr Manhattan I see on my TV depends on the pixels on the screen and the various mechanical processes behind it, but an understanding and description of the former is nothing like an understanding and description of the latter.

In which case I would just deny the thought experiment as being incoherent, since it can't even say what being envatted means.

And that's the very thing I would use to argue against realism. You can't say what it means to be a tree or to exist without describing what such things look or sound or feel like. So for them to be something other than the appearance is incoherent.

Your proposed noumena is exactly like the not-really-a-brain in a not-really-a-vat.

What gives the skeptical scenarios of being a BIV or in the Matrix, it's all a dream, or Descartes's demon power is that we understand well what those scenarios mean. What is problematic for the noumena is that we can't know what it is, by definition.

That doesn't follow. That A depends on B is not that an understanding of A gives us an understanding of B. — Michael

It follows that we can't make an argument that A depends on B if we don't understand anything about B. It's like saying we could be BIVs, but the brain and the vat aren't anything like brains and vats that we experience.

So what are they then, and how could that scenario possibly hold? You see, the BIV gets it's meaning from what we experience.

What is problematic for the noumena is that we can't know what it is, by definition.

..

It follows that we can't make an argument that A depends on B if we don't understand anything about B. — Marchesk

In which case you can't make an argument that phenomena depend on noumena.

In which case you can't make an argument that appearances depend on something else — Michael

You need to add "entirely unlike appearance" to make that work. If reality is entirely unlike anything we perceive or conceive or talk about, then we have no basis to say there is such a reality. But I'm not stating that. I'm stating that what we perceive, think and say is dependent on that reality such that we can't be totally in the dark.

You need to add "entirely unlike appearance" to make that work. — Marchesk

You said that we can't know what noumena is and that we can't say that A depends on B if we don't know what B is. Therefore, from your own premises, we can't say that phenomena depends on noumena.

Right, but I'm not arguing for noumena. That's Kant's notion, which I reject.

You need to add "entirely unlike appearance" to make that work. If reality is entirely unlike anything we perceive or conceive or talk about, then we have no basis to say there is such a reality. But I'm not stating that. I'm stating that what we perceive, think and say is dependent on that reality such that we can't be totally in the dark. — Marchesk

Then you've begged the question and presupposed that the world of appearance is something like the mind-independent world.

Then you've begged the question and presupposed that the world of appearance is something like the mind-independent world. — Michael

I'm providing an argument against one of the criticisms of realism, which is that an ideal theory could be completely untrue. It's a move available for realists to make. The criticism arises from one understanding of realism. But if the realist adds that the mind is dependent on the real such that an ideal theory can't be entirely wrong, then they have a rebuttal.

I'm providing an argument against one of the criticisms of realism, which is that an ideal theory could be completely untrue. It's a move available for realists to make. — Marchesk

And the argument begs the question. If "A depends on B" can only be true if A is like B then "an ideal theory depends on a mind-independent world" can only be true if an ideal theory is like the mind-independent world. But what the realist needs to show is that an ideal theory really is like the (supposed) mind-independent world.

The realist just needs to show that their conception of mind-independence isn't such that it requires an ideal theory to be completely untrue.

To put it another way, the realist does not need to maintain that our experiences and thoughts are entirely different from reality. What matters is that the world is not dependent on us.

To put it another way, the realist does not need to maintain that our experiences and thoughts are entirely different from reality. All that matters is that the world is not dependent on us. — Marchesk

But to do that he has to show than an ideal theory can't be false. So how does he do that?

It's incoherence. The fact that our experiences are not the objects we observe. Ideal theory cannot be true or false because it completely fails to address instances of our awareness. It confuses our existence (our experience) for what we experience (the existence of objects).

Ideal theory only makes sense in a context where the observer is equivocated with the observed.

If the real world is what appears and if the anti-realist accepts that things appear then the anti-realist accepts that there's a real world. — Michael

Does the ant-realist believe that the fact of the appearance of things is independent of what anyone believes and/or experiences? Does s/he believe that there could be any machinery responsible for the appearances, that does not itself appear?

Does s/he believe that there could be any machinery responsible for the appearances, that does not itself appear? — John

Depends on the variety. The phenomenalist wouldn't but the internal realist would, for example.

Does the phenomenalist say there cannot be any such machinery, or merely claim that we could not know anything about it?

Is the internal realist an anti-realist, then? Is so, it would seem somewhat contradictory...

If the internal realist claims there can be such a machinery, but admits that it might not be experienceable, then would that not be tantamount to admitting that there could be a reality that is not internal?

Does the phenomenalist say there cannot be any such machinery, or merely claim that we could not know anything about it? — John

He says there isn't such machinery.

Is the internal realist an anti-realist, then?

Yes.

Is so, it would seem somewhat contradictory.

Not really. It's a rejection of the metaphysical realist's claim that "the categories and structures of the external world are ... ontologically independent of the conceptualizations of the human mind."¹ That's different from rejecting the claim that there is a causally independent machinery.

If the internal realist claims there can be such a machinery, but admits that it might not be experienceable, then would that not be tantamount to admitting that there could be a reality that is not internal?

The part that causally explains phenomena, yes. But in contrast to the metaphysical realist, the internal realist rejects the claim that any of the more meaningful things we talk about – "the chair exists", "the cat is on the mat", "e = mc²" etc. – say anything about these non-internal parts of the world.

So it allows for an ideal theory that doesn't correspond to mind-independent things, and is comparable to model-dependent realism in science.

¹https://en.wikipedia.org/wiki/Hilary_Putnam#Metaphilosophy_and_ontology

The part that causally explains phenomena, yes. But in contrast to the metaphysical realist, the internal realist rejects the claim that any of the more meaningful things we talk about – "the chair exists", "the cat is on the mat", "e = mc2" etc. – say anything about these non-internal parts of the world. — Michael

What motivates the internal realist to be an internal realist as opposed to a phenomenalist? Why think there is some sort of mind-independent machinery that we can't talk about? I suppose it's the same reason Kant thought there was noumena, but it suffers from the same problems.

Perhaps to avoid any possible problems regarding other minds and shared experiences that might arise under phenomenalism and to provide an explanation for the origin and regularity of phenomena.

That makes sense, although the explanation for the origin and regularity of phenomena is relegated to the utterly mysterious.

But in contrast to the metaphysical realist, the internal realist rejects the claim that any of the more meaningful things we talk about – "the chair exists", "the cat is on the mat", "e = mc2" etc. – say anything about these non-internal parts of the world. — Michael

I would agree with you about the first two examples, which ostensibly speak only to an experience which can be thought to be 'internal' to, in the sense of being circumscribed by, language; but "e=mc2" speaks to nothing internal to our experience, but rather says that the fundamental constitution of matter is such that it holds an unfathomable potential for an enormous release of energy. This latter actually is a metaphysical claim since we can never see (experience) this potential or the energy, but merely what are inferred to be the effects.

I would agree with you about the first two examples, which ostensibly speak only to an experience which can be thought to be 'internal' to, in the sense of being circumscribed by, language; but "e=mc2" speaks to nothing internal to our experience, but rather says that the fundamental constitution of matter is such that it holds an unfathomable potential for an enormous release of energy. This latter actually is a metaphysical claim since we can never see (experience) this potential or the energy, but merely what are inferred to be the effects. — John

So you're a scientific realist. But that's not the only approach to science. There's instrumentalism and the aforementioned and related model-dependent realism. The internal realist would adopt one of the last two interpretations.

I don't see how what I said is necessarily connected with scientific realism. Basically all I asserted was that "e=mc2" cannot be made sense of as an empirical statement in the same way as "the chair exists" or "the cat is on the mat" can. Can you offer any alternative way in which it could be expressed in ordinary English other than the non-empirical way (or kind of way) I already exampled?

Note, when I write "non-empirical' what I have in mind is that ordinary language expressions of the formula consist in speculative statements about posited powers or forces. I don't see any other way they can be understood.

Basically all I asserted was that "e=mc2" cannot be made sense of as an empirical statement in the same way as "the chair exists" or "the cat is on the mat" can. — John

e = mc² is a formula which describes and predicts observed phenomena. I don't see how that's anything other than an 'empirical statement'.

I don't see how what I said is necessarily connected with scientific realism.

My mistake. I thought you were suggesting that the equation ought to be understood according to realism rather than instrumentalism (or model-dependent realism).

E=MC2 is not an empirical statement. It belongs to the the theoretical side of science. Nobody observes an equation, or law of physics. Rather, theory is used to make sense of observation.