Or to put things a little differently, and perhaps more clearly, the Crane/Churchland line seems to force the skeptic to a position in which they will have to defend the following modus tollens
1 If some item of knowledge is physically encodeable, then it is discursively learnable
2 The item of knowledge Mary gains is not discursively learnable
_________________________
The item of knowledge Mary gains is not physically encodeable

The support for premise 1 would of course have to be independent of any issues concerning Mary, and I gave an indication of one way that might be done in the previous post.

What (if anything) Mary learns from seeing colors is either discursively-learnable or it is not. We can consider these two cases separately.

OK, so this argument puts off the question of accepting whether or not Mary learns anything.
I guess against this argument, the skeptic would have to push the investigation of the supposed distinction between knowledge being discursively learnable and knowledge being physically encodeable. What does "physically encodeable" mean? Given the representationalist background of most versions of physicalism these days, I suppose one proposal for a gloss of "physically encodeable knowledge" would be knowledge the content of which is entirely representational in or through a physical form. So, a premise of the Churchland/Crane/whoever argument is that there is a distinction between knowledge that is discursively learnable and knowledge, the content of which is entirely encodeable in a physical medium. So what is content? Content is propositional. Even if one accepts the idea of non conceptual content, that is not to accept the idea that there is content that cannot be expressed in terms of propositions, it is just to accept that the person having the mental state with that content need not have the resources to state those propositions. So if all content is propositional, then not only is all discursively learnable knowledge physically encodeable, all physically encodeable knowledge is expressable as propositions and so is discursively learnable. Thus, perhaps, one way in which the skeptic might try to deal with the Crane/Churchland/whoever argument by collapsing the distinction required by one of its premises.

Is there a distinction between doubting the proposition that a sentence expresses, and doubting what proposition that sentence expresses? It seems to me that there is, but that it is a distinction that threatens to be collapsing under your defence of KILPOD.

To question whether or not x is an ant is to question what "ant" means.

Well, that depends on the reference of "x" doesn't it? I can imagine being uncertain whether a particular thing referred to by x in the expression "x is an ant" is indeed an ant or whether in fact a termite, for instance. That would be a case of questioning whether x is an ant or not, yet it is not, at least not clearly, a question about what "ant" means. It would be more natural to think that it was a question as to whether, given that the meaning of "ant" and "termite" are agreed, the x should be classed as one or the other. There might be cases where it really is not clear even to experts whether the x should be classed as an ant or a termite, and there one might think that it is actually the meaning of the terms that is being brought into question as well, but that is a very specific kind of case.

This is a very common and deep-rooted misconception. It simply is not the case that knowing all the facts, about the physical state of one's brain when one has some particular knowledge, is the same as having one's brain in that state, and physicalists can reasonably propose that unless one's brain is in that state, one does not have that knowledge.

That there is a distinction between, on the one hand, being in a physical state P, and, on the other, knowing all the facts associated with being in a physical state P, does not seem to be a distinction over looked either by Jackson or by me. The issue concerns in what that distinction consists. I can know all the facts about the physiology of sitting in a chair. What knowledge or other epistemic quality do I gain by being in that state for the first time that I did not already have before being in it? Here the reply "nothing" seems to have as much going for it as "something". The intuition on which Jackson's argument and mine rely is that "something" has a stronger pull when the example in question concerns seeing something red for the first time. As I have already admitted, it is just an intuition. However, if you accept the intuition, then something substantive should be said about what it is that is gained, and that is not a burden that falls on the materialist alone. The dualist also has to give us something to work with. For what it is worth, I do not believe either side has a particularly coherent idea about what it is that is gained that would pin it down sufficiently to provide grounds for further investigation.

It would be really useful if, in your next reply, you could address this issue alone,

Sorry, I am not clear on exactly what issue it is that you want me to address. The paragraph preceding the one from which the above quotation is extracted makes it look like the point you want to make is that if current science is incomplete, then there should be no philosophical arguments brought forward to eliminate a given avenue for its advancement. Is that the issue you want me to address? Or is it that there should be no such philosophical arguments brought forward which contain as a premise that current science is incomplete?

The word "ant" happens to refer to a certain type of insect, and "elephant" to a certain type of large, ruminant mammal, but it might have been otherwise (that it might have been otherwise is a logical possibility).

This seems a little beside the point. The sentence "Ants are not elephants" might have expressed a different proposition to the proposition that it actually expresses. No one is denying that, why would anyone deny it? But admitting that is not the same things as admitting the possibility of doubt concerning the proposition that the sentence actually does express. It is merely to allow the possibility that words used to express that proposition may have meant things other than they actually do. That is not doubt, that is just accepting alternative linguistic possibilities.

In any case, if you are attempting to lay down a necessary or sufficient or necessary and sufficient condition for what counts as knowable, you are not being very Wittgensteinian, at least not under one interpretation of what Wittgenstein was trying to do.

This sort of thing is common in all fields of incomplete knowledge.

But the arguments, Jackson's and mine, are based on the idea that Mary's knowledge is complete, at least complete insofar as to make any examples of epistemic gaps drawin from the current state of physics/chemistry etc irrelevant. Of course the current state of science is far from complete. One way of expounding on what that incompleteness means is to home in on the idea there are observable phenomena that our uncontested theoretical apparatuses do not allow us to predict as being observable. Hence my definitions of what it would be for Mary to have the complete knowledge required of her.

I do not think I am misrepresenting you when I paraphrase your position as being that a physicalist must either reject the premise that Mary learns anything on first seeing colors, or must give a full (or almost complete) physical accounting of what she does learn.

I think I allowed myself to be misrepresented, since if you are saying that the two premises of my argument concerning what it would be to have complete physical knowledge are up for grabs as well, sure, I'll concede that. None of the premises are a priori truths. In fact I think I suggested that some idealists would home in on challenging what I am saying would count as complete physical knowledge. I think I can see how an idealist might try responding, but what of a materialist monist? Would the objection be that physics and the other special scienses will never reach completion?

The point is that if a materialist monist responds along the lines that Mary gains something, then when asked "what" just replies something that is physically encoded but we do not yet know, then the fact that we do not yet know it is irrelevant, since the argument rules out Mary having such gaps, or attempts to. If, on the other hand, a materialist monist says Mary now knows what it is like to see red, and that knowledge is physically encoded, then that means there is some set of propositions about Mary's physical state which describe what is encoded, and so expresses what it is she comes to know. But by hypothesis Mary had the tools at T to predict that those very propositions would be true, with a given range of liklihood perhaps, at time T+x, which puts strain on the claim that she has gained any knowledge. I suppose there is the avenue to explore that she gains extra confirmation of the truth of the time indexed propositions, although she did not need that confirmation. Althernatively, as I put it in my previous post, she gains knowledge that the probability distribution has collapsed onto a specific member of the set of possible propositions.

Anyway, either complete physical knowledge is possible or it is not. If it is not, and the admission of this has been forced on the basis of arguments involving people coming to know things when they see things for the first time, then dualists have it. If it is not possible for other reasons, then dualists still have work to do. If it is possible to have complete physical knowledge, then I suppose we need to agree on how exactly to spell out what that would mean. I proposed glossing it in terms that provide the tools to predict all observable events, but maybe there are better alternatives.

Editing my own post and specifically concerning this remark

" then that means there is some set of propositions about Mary's physical state which describe what is encoded, and so expresses what it is she comes to know. "

I suppose there is a riposte here that what is encoded can only be stated as knowing what red looks like, and that there is no alternative way of expressing that content, but that admitting this does not entail that the content is not encoded physically. Of course, accepting this might involve having to buy into a representational theory of mind, which personally I do not, regardless of any issues about this knowledge argument. However, regardless of that, is that riposte really available for a materialist monist? If the content encoded can only be expressed as "knowing what red looks like" then there could be no identity expression of the kind "knowing what red looks like is identical to ........ " where ........ must be precisely an alternative way of expressing that same content. You might want to say that materialist monists do not need to make such identity statements, but their monism, in the end, probably does require them to do so. One could be eliminative, but in which case there is no such thing as "knowing what red looks like" anyway, so the eliminativist would simply be rejecting the idea that Mary gains anything when she see a red tomato.

But how, knowing what "no ant is an elephant" means, is it possible to doubt it? Sure I may not know the meaning of "ant" and/or I may not know the meaning of "elephant" but then I simply do not understand the proposition that no ant is an elephant, it might just as well be the statement that no figgy is a wiggy. Once a proposition like that is understood is it possible to doubt it? For instance, I understand the proposition that ants run in circles when injected with amphetamines. I can also doubt it, since for all I know about ants they can are unaffected by amphetamines. This marks a distinction between kinds of proposition. Now, whether that is a distinction in kind or in degree or not is another matter.

Interesting. So your claim is that if a proposition can be known, then it can be doubted. What about a proposition such as "No ant is an elephant"? Is there a way of doubting this? Obviously I mean more by "way of doubting this" than just uttering the expression "There might be an ant that is also an elephant". The doubt has to have some substance. If there is no substantive way to doubt it, does that mean it is not knowable as a proposition?

As far as I can tell, these objections work just as well as a response to your argument as to Jackson's.

It depends. It seems to me the materialist monist would have to reject the premise of my argument that Mary does gain epistemologically when she confronts, or is confronted by, the red tomato. That's an option of course, and one which towards the end of your post, you hint at. However, I am still unconvinced that the materialist monist can accept the premise that Mary gains something and offer a response to the question what. You write:
"According to the physicalist premise, these changes, and these changes alone, bring about Mary's new knowledge,"
You seem to agree that what Mary knows prior to the event includes all the changes referred to, so what is Mary's new knowledge that is brought about by them? Is it an ability, is it some new set of propositions, is it some other kind of knowledge? That question does not seem to be answered in the paragraph of yours I extracted that quotation from. You mention only that the physicalist just needs to point out that it is information encoded in physical form, but what is that information?

As to your burden of proof point, I was attempting to give the basis of an argument that avoids tossing the burden ball. As I say, there is a burden just as much on dualists to give a substantial account of what is learnt by Mary. Idealists as well would need to say something, but would probably opt for denying that Mary gains anything and instead say that the intuition that she does gain anything is based on a false understanding of what it is to know all the physical facts, something that the materialist monist could also try. In any case, idealists have different tricks up their sleeves and don't generally, at least as far as I am aware, use Jackson's argument, or any variant of it, at all.

Regarding the definition of physicalism I gave, you are correct that it requires Mary to have the theoretical apparatus to predict, with appropriate statistical distributions where necessary, what events will occur in the future. For sure this raises issues about determinism, but that one area of metaphysics should have a dependence on or be related to another area is no big surprise: it is probably only in professional analytic philosophy circles that anyone pretends, or has to pretend, that metaphysics can be cut into bite sized chunks. I suppose it might be said that my argument requires that the timeindexed propositions that Mary knows at T can only involve statistical distributions of event occurrences, and that at time T+x the distribution curve collapses to a point and so Mary comes to know a proposition without any statistical hedging, which she could not have known before. Not clear to me if that would help the materialist monist though, I'd have to think about it.

That means the statement "all physical things are sensory perceptions" is false

No, it means it might be false and certainly a materialist is going to claim that it is false.

some physical things are not sensory perceptions. Please name some.

I'm not a materialist, I invite those who are to respond fully. However, let's kick the ball rolling by offering up "the football in my shed". Seems like a reasonable candidate to me. After all, when I look at the football in my shed there might be a sensory perception of that football, but that does not entail that the football is that sensory perception.

2. relating to things perceived through the senses as opposed to the mind; tangible or concrete.

I'm focusing my attention on 2, but do include 1 in this, specifically the part where it says "perceived through the senses" and we know the senses are unreliable (think hallucinations) and can be deceived; if so, the physical could be an illusion.

Note the "tangible or concrete" in definition 2. Things which are tangible and concrete are generally put in opposition to those that are merely illusory.

2. All physical things are sensory perceptions

No materialist is going to accept this premise. The most you will get them to accept is that physical things can be objects of sensory perceptions.

Well, if you haven't reached the conclusion that physicalism is false, then you have not completed your task of, as you put it, circumventing Churchland's attack [1].

One can circumvent objections by changing the argument, which is effectively what I did: it is certainly not Jackson's original argument. It is an argument that essentially states that if you accept that Mary gains anything epistemologically, you are obliged to give an account of what she gains, and the account given must not result in Mary getting something that she already had or could have obtained without seeing the red tomato.
I agree that there is some unclarity about what physicalism is, you mentioned Tim Crane, and one of his earlier papers was on exactly that point. I tried to encapsulate a rough approximation of physicalism, and let me try to be less circular by saying that Mary having complete physical knowledge would give her the apparatus to predict every measurable event in the world, given knowledge of the measurable starting points. Measurable here means measurable by apparatus available to anyone. So, when Mary sees, at time T+x, the red tomato, she is in some overall measurable state. At time T she is able to predict accurately the measurable state she will be in. Let us suppose she does this, i.e. at time T calculates all the measurable effects on her and her environment of her coming to see a red tomato without the aid of optical equipment. She will write down a number of statements such as "At T+x my cones are excited in such a such a way", "At T+x+dx my optical fibres are excited in such and such a way", "At T+x+dx+dx my frontal lobe will be excited in such and such a way" and so on and so forth. At T she has this entire set of time indexed propositions covering the moment she is confronted by the red tomato up to, let us say, two seconds afterwards. We make the assumption also that any abilities she has at T+dx are also included in this set of propositions, perhaps in the form of conditional statements of the kind, if at time T+dx+dz I am again confronted by a red thing, then such a such a measurable effect will be observable. She needs no confirmation of the truth of these time indexed propositons, because her theoretical apparatus is complete and true. I.e: she knows all these propositions.
The question now is, given that Mary is in that position, does she still gain anything epistemologically at all when she sees the red tomato? That she does is based on the intuition pump, but we do not have to accept intutions, which are after all not much more than guesses. It is a question for the idealist and dualist as much as it is for a materialist monist. The materialist monist has the luxury of responding "no", and thereby rejecting the intuition, but I suppose then has to deal with the persistence of the "illusory" intuition that Mary would gain something. The idealist and dualist must really respond "yes" and, as you hint, need to say something about what she does gain, which usually leads them into hand gesturing about qualia and so forth. However, the materialist monist who responds "yes" also needs to say something about what Mary gains epistemologically and what she gains must meet some criteria. The first of these is, of course, that whatever is proposed should not already be included in the set of all the time indexed propositions previously mentioned, since otherwise it is not something she gains epistemologically. The second is that whatever is proposed is genuinely something epistemological in nature. This is where, presumably, a materialist monist might want to try suggesting that Mary gains some measurable abilities. The problem then is to state what those abilities are in terms that do not quantify over anything not quantified over in Mary's theoretical apparatus, and is also an ability she genuinely gains that is not included in the set of propositions covered earlier. Faced with that, the materialist monist might point out that the assumption was that the set of propositions included all conditionals covering all the abilities that Mary has at time t+x, so the challenge to provide an new ability she gains cannot be met. Fair enough, so either the materialist monist back tracks and says that Mary does not gain anything epistemologically when she sees the red tomato, and so face the question of accounting for the illusory intuition that she does and its persistence, or the materialist monist tries to come up with some other kind of epistemological gain Mary makes that is not based on her gaining abilities or propositional knowledge. FOLLOWING SENTENCES ADDED: Or perhaps the materialist monist might try to deny that abilities can be reduced to conditional propositions the truth of which can be determined by taking measurements. But that looks like admitting that there are abilities that we have that fall outside of the scope of Mary's theoretical apparatus.

1. All physical things are things that could be illusions
2. No "thinking things" are things that could be illusions
Ergo
3. No physical things are "thinking things"

Premise 1 seems to be a contradiction, since under one understanding of "physical" things that are physical simply by definition are not illusions. The argument might need to be rephrased as
1. Anything that can be taken to be physical could be an illusion.
2. No thinking things are illusions
3. Thinking things cannot be taken to be physical things.

However, the argument thus stated does not rule out the possibility that thinking things are physical things, just that they cannot be taken to be such. Materialist philosophers love to point out this kind of epistemological/metaphysical distinction, as if it were clear cut. Anyway, to get to a conclusion that thinking things are not physical things, you would need an extra premise to the effect that if something is F then it can be imagined/conceived/taken to be F, which might be a little difficult to defend.

I defined what I meant by being in possession of all the physical facts: it is to have the theoretical apparatus sufficient to predict every physical event or fact. There is no equivocation in the argument I gave, which does not even end with the conclusion that physicalism is false The argument simply points out that if one accepts that Mary gains something the question arises, for everyone: what does she gain? She does not come into possession of a new physical fact, since by hypothesis she was already in a position to predict, and thus be in possession of, all the physical facts that take place when she sees the tomato. If you are a physicalist, and you accept that Mary gains something, which as I pointed out you do not have to accept, you are constrained to provide a description of what she gains that i. does not introduce anything new that is not already quantified over by the theoretical apparatus Mary already has, and ii. nevertheless correctly accounts for what Mary now has or is now able to do.

The only way for science to be necessarily unable to explain consciousness is for consciousness to be proven with apodeitic certainty NOT to be an empirical condition

an empirical condition of what?

Let's try to circumvent Churchland's attack without buying into the theoretical apparatus that Churchland and Jackson buy into:
1. Mary at time T is in possesion of a complete theoretical apparatus that allows for the prediction of all future events, or for the QM theorists lurking, allows for the prediction of the probability distribution of all future events
2. As a matter of definition only, anyone with that kind of knowledge knows all the physical facts.
3. Lemma: from 1 and 2 Mary at time T is in possession of all the physical facts.
4. Mary, up to time T, has never seen any colours other than white and black and the 50 or so shades of grey in between.
5. Mary at time T+x sees with her own eyes a red tomato, and not by seeing a black and white image of a red tomato, nor through any other kind of technological apparatus.
6. Mary gains something at T+x that she did not possess at T.
7. Given Lemma 3 and premise 6, what Mary gains is not knowledge of a physical fact.

Premise 6 must either be denied or accepted, whether one be a physicalist an idealist or some wishy washy compromise between the two. How do we motivate that it must be accepted? "Well, put yourself in Mary's position" is the standard technique to do that. So, we imagine ourselves living in a world which really has just the colour range of old film noir, and suddenly we stumble across a red tomato, or perhaps a pair of red shoes. That might pump the intuition that our lives are suddenly richer than they were, and so we have gained something.

If we accept that intuition, and intuition is all it really is, we then face the problem of describing what exactly it is that we, and Mary, have actually gained. Here dualists/idealist and so on have the upper hand, since they have a more or less unrestricted ontological menu to choose from. Physicalists, though, need to be careful. They need to express what it is Mary gains, but they need to do that in such a way that the description falls outside of the complete theoretical apparatus mentioned in premise 1. Just to give a taste of the problem here, suppose the conversation between a phyiscalist and an early incarnation of Frank Jackson goes like this:
Physicalist: Mary gains an ability.
FJ: OK sport, what ability?
Physicalist: The ability to recognise red things.
FJ: She could alread recognise red things. Tomatoes are red things and when she was given black and white pictures of vegetables and asked to pick out the tomatoes, she had no problems.
Physicalist: That's not what I meant. I meant she gained the ablity to recognise red things on the basis of their colour, not their size or shape.
FJ: But she could already recognise red things on the basis of their colour, not their size or shape. Mary has some remarkably sensitive measuring equipment and given a room of coloured objects, on the basis of the wavelengths of light they are reflecting, and accounting for the ambiant conditions, she is able to pick out those reflecting in the 700–635 nm range, and those are usually red things.
Physicalist: That's not what I meant either. I meant she gains the ability to pick out red things just by looking at them.
FJ: Are you sure about that? What if the next tomato she sees is an unripe one and she is just using her eyes? You and I would call it green. Unless Mary can rush back to her equipment, she's probably going to lump it in with the red things.....hell of an ability she's gained there, sport.

Obviously, the physicalist will have a retort.

OK? Make any sense at all?

To an extent, thanks, but I think what I really need to do is go back to CPR and look again at how Kant distinguishes images from schemata.

A scientific answer is an answer the requires, in principle, only understanding consistent with current or future established empirically-verified scientific models of reality. I'm anticipating the question "What is a scientific model in this context?" whose answer will yield another "What is a scientific X in this context?".

Well yes, if you continue to drop the adjective "scientific" into your definitions of what you mean, in specific cases, by the use of that adjective, then you are inviting all those questions, and maybe more.
A: A scientific answer is an answer the requires, in principle, only understanding consistent with current or future established empirically-verified scientific models of reality.

B: A scientific answer is an answer the requires, in principle, only understanding consistent with current or future established empirically-verified models of reality.

Is there some important difference between A and B?

Indeed food for thought:

As soon as you say, “I understand what a triangle is”, you’ve already brought up a mental image of one, otherwise you would have no means to justify such a claim.

Why can't I justify my claim to understand what a triangle is by drawing one? Why do I need to bring up a mental image, rather than a physical one on paper?

Also, how do you see this:
"images are the schemata of our representations."
tallying with this, emphasis added:
"In truth, it is not images of objects, but schemata, which lie at the foundation of our pure sensuous conceptions"
?
On one reading this is simply denying that schemata are images, which of courses raises the question of what schemata are, but it seems that one can accept schemata are involved in all representations and conceptions without accepting that mental imagery is.
I appreciate that the second quotation is lifted out of a very complex work, so perhaps there is somewhere in Kant an argument to show that whilst schemata are not images, they depend on them?

visual cortex

There could be sighted creatures without visual cortexes, at least that seems possible. So even if you just meant by "mental imagery" "whatever goes on in the visual cortex", you still do not have something that need always be involved in sight. Anyway, that to one side, I am still not clear what you mean by a scientific answer. You've indicated what you do not mean, but not what you do mean.

"How was the Earth created?" is a scientific question with a scientific answer.

Well, since your definition of a scientific question is one with a scientific answer, that becomes almost tautologous. I presume you meant to say something substantial, but what the substance is I cannot figure out unless you fill out what you mean by the phrase "a scientific answer".

Just to reiterate, by "scientific question" I mean a question whose eventual answer is a scientific one.

Just so I don't have to reread the thread from page 1 can you define what you take the phrase "a scientific answer" to mean? Can scientific questions have non scientific answers as well as scientific ones? E.g. take the question "Why am I asking you these questions?" Under one way guessing at what you mean by "scientific answer" you might mean by a scientific answer one that is steeped in physiology, neurology, cogntive science etc etc. On the other hand there is the answer "Because I am generally curious about what you might mean". The latter would seem to be a non scientific answer, although that rests on assumptions about what you mean by "a scientific answer", but in all cases it seems to be a perfectly respectable one for all that, and it is also, as it happens, true.

There is a metaphysical tenet that says images are the schemata of our representations, the real as things given to us, or merely thought, as things might appear to us if they were real. This is clear, when we consider, e.g., the tickle between the shoulder blades. First is the sensation of a presence, then the image of something from experience which the tickle might represent (a bug, a hair) or from mere thought (a ghost, your friend playing a trick on you).

Is there an argument for this tenet? Perhaps there is mental imagery involved in my recalling how my shoe ended up tied, but that does not entail that mental imagery is involved as I watch my hands manipulate the shoe strings. Note that I am not denying that there is something called mental imagery, nor that it might be problematic from a philosophical or scientific perspective. I am merely posing the question of what arguments or evidence there is for what you claim to be their ubiquity.

Or is your point that this is an example of a meaningless question, as evidence that there are no meaningful unscientific questions?

To be perfectly honest, I do not know. I do remember once being amongst a relatively high number of people who bandied around terms like "mental imagery" and "visual experience" as if they were pervasive elements of sight, and then someone pointed out to me that my use of those terms was theory laden, and the theory with which it was laden was not common sense and was based on presumptions not evidence.

how mental imaging occurs

OK, I understand, you seem to be of the opinion, shared by quite a few philosophers and scientists it must be said, that every time we see anything, mental imaging is occuring. How would you convince someone who denied this? I mean, suppose someone were to say to you "for me, mental imagery is the kind of thing I might engage in as I day dream, or try to bring to mind the look of that woman I saw yesterday, etc etc but it is not the kind of thing I engage in, or at least not typically, when I just look at a wall painted red". Looking at such a wall might of coure provoke someone into think about some red headed woman, and that might involve mental imagery, but what is the empirical evidence, or philosophical argument, that every time anyone sees anything that there is mental imagery going on? Are you relying on something like the old, and much contested, arguments from illusion or hallucination? Or is there something else you would bring to bear in response to the mental imagery sceptic?

I cannot personally explain why I experience a particular hue of red when I look at my dining room wall -- that is a scientific-seeming question that is unanswered -- but I can explain why that perception persists under fixed lighting conditions -- that is a scientific question that is answered.

Could you be clearer about the two questions you imagine to be here please, because under one understanding of what you are saying the "why" questions both have exactly the same, entirely mundane response: "because it is daylight and your wall is painted red", which would seem to indicate that they are, in fine, precisely the same question.

:up: So, on the Kantian view, even if noumena are possible, we have not , and indeed cannot have, the slightest reason for believing them to be actual. Does that sound right to you?

The “grounding” of appearances is exactly what noumena are supposed to be for. All I’m suggesting is that we don’t need to suppose there is anything about noumena other than that they ground such appearances

If you want to define "noumena" as "whatever grounds appearances" go ahead, but it is completely topic neutral since even appearances can ground appearances.

The problem with Mill's position, as I'm sure you know from Philosophy 101 is that if something is claimed to be possible, permenanently or otherwise, there should be something to say about what grounds that possibility. At least, when we customarily use modal language there is an expectation that we be able to justify what we are claiming is possible. What grounds Mill's permanent possibilities of sensation? If you are tempted to respond "Just a propensity to appear a certain way to certain kinds of minds", you should appreciate that the notion of a propensity is steeped in modality itself, and effectively the response just reduces to "permanent possibilities ground themselves", which is more like an absence of justification than a genuine response. If, taking another tack, we respond with the idea that the permanent possibilities of sensation are grounded by the actual sensations we already have or have had, Mill's position collapses more or less into a version of Berkeleian idealism. Incidently, Berkeley's position was not that reality is "just an appearance", he was perfectly well aware that he needed to account for the distinction between mere appearance and reality, but he does so, with the assistance of his god of course, whilst rejecting that there is such a thing as matter. Kant is unkind to Berkeley, by the way, and his so called refutation of Berkeleian idealism is far from a knock out punch.

I know Trump was elected president, I just don't believe it.

"To produce" is at best a loose way of saying what I'm trying to say, but all our language is causal and temporal so what else can I do

Perhaps stop talking about noumena and "really real" things?
I can think of some context where "really real", "actually real" and so on might make sense, but they are all cases of insisting on the reality that how things appear are how things are.

If we give up any notion of noumenal properties besides a persistent propensity to produce particular kinds of phenomena to particular kinds of observers in particular contexts, then this whole problem goes away

Isn't the problem with this, at least on the Kantian view anyway, that concepts such as "to produce", which are causal in nature, only make sense in the realm of phenomena and so to think that noumena produce phenomena in any circumstances is incoherent. I know Kant tries to make sense of the idea of noumenal causation to deal make room for freedom of will, but not entirely successfully.

Having no such information would entail me existing in some kind of weird superposition of all 3 choices.

That needs arguing for, not just stating.

Ability or factual knowledge are just different encodings of information

That needs arguing for, not just stating.

So where does the information come from to select 3)?

Have you considered the idea that there is no such information? There is a distinction between ability based knowledge and factual knowledge, between knowing how to play a guitar and knowing the answers to a history test. Whilst the concept of information might be useful in analysis of having the latter kind of knowledge, and in the analysis of acquiring the former kind, that alone does not entail that all knowledge just is possession of information. De se reasoning may not involve gaining new information. At least, you have yet to argue that it must.

You're welcome. I wish you well. Maybe you can find some better midground between the harsh austereness of my paragraph, and the somewhat apologetic softness of yours.

When I look through for ways to make things less personal, all I see are opportunities to falsely claim my own views as indisputable facts

There is always a danger in philosophy of presenting a statement as truth when in fact it is false, or at least dubitable. With the possible exception of Socrates, who asked questions rather than made statements, I can think of no philosopher who avoided doing so. However, if the statement concerned is preceded by good arguments or reasoning for believing it to be true, it would be a very sensitive person indeed who would be affronted in any way by your audacity in passing it off as a truth. They might take it on as a challenge to prove you wrong, but is not that precisely one thing that we should be inviting as writers of philosophy? In any case, if you want to hedge a statement, whilst occassionally an "in my opinion" or "as far as I can see" might be just what you need, there are usually always impersonal alternatives to try out for size.

And if you can't resist personalising it a bit, perhaps amend the final sentence to:
Everyone, no matter their expertise or power, remains fallible, even me.
Edit: strictly speaking, grammar requires that "even me" be "even I", but that seems inelegant. Anyway, as I say, this is just a first draft which you should feel free to flush away like a used sheet of toilet paper.

Allow me, let us take the following paragraph of yours:

But I am not saying to automatically reject all claims made by all authorities. I am not saying that everything every religion claims is wrong, be they claims about reality or ones about morality; nor that everything teachers teach in schools is wrong, or that you should disregard all laws put forth by all governments. I am actually very much in favor of defering to expert opinion on matters about which you have little information with which to form your own opinion. By rejecting appeals to authority, I am only saying to hold all such opinions merely tentatively, remaining open to question and doubt. If you are unsure of the answer to a question yourself, and some particular individual or institution claims to have looked into it extensively and become very confident in the truth of some answer, I think it's fine to tentatively accept their opinion as probably the right one, for lack of any better reason to think one way or another.

Here is a first draft depersonalised version:

The recommendation is not, though, to reject out of hand every claim made by any authority. In cases where we lack information, or even the resources to obtain it, we may have good reasons to defer to the testimony of an expert, the legislation of a government or the edict of a pope. However, deference should neither become, nor be confused with reverence. Everyone, no matter their expertise or power, remains fallible.

I don't think your neurology is the problem, it's your philosophy.

as it was the standard model of brain function before the neural network revolution

There was never a standard model of brain function, at least not anything analogous to the standard model of particle physics. Consequently, there was never a "neural network revolution" to over throw it.

Illusionists, in this philosophical sense, certainly have one problem, somewhat of their own making: that of explaining how it is that we are supposedly victims of an illusion when we think, if we do think, that mental states have phenomenal qualities. They also have the problem, in that context, of explaining why it is that the illusion they claim we have has the character it does, rather than some other possible characteristics it could have had, and specifically why it is that the illusion that we do have is recalcitrant to illiminativist theories, for even illusionists will have to admit that their position is on the fringes of the philosophy of mind, and it is nigh impossible to convince many people of it.
Suppose I awake one day and I ask for some toast for breakfast and someone tells me that I am subject to a bread illusion because nobody has ever baked bread, bread has never been a staple in any national diet, and I could not ever have eaten it in any shape or form. As unlikely as I would find this, it is very easy to imagine being shown around the world I have awoken to and end up being convinced that all the mnemonic evidence I have for my conviction that I should be able to get some toast is in fact illusory. Faced with the breadless world facts, my problem will no longer become "what is wrong with the bread illusion theory" but "what is wrong with me". However, an analogous tale for the "mind illusion", i.e. one I would accept as reversing the burden of the problem, seems to be missing. Why is that? This might also be thought of as part of the problem illusionism has generally, but it is a detail that is not given a great deal of importance.
In any case, what illusionists tend to do in reponse to all their problems, is drag us through the mud of representational theories of mind. One already has to buy into that general approach in order to be really bothered by what illusionism has to say. My suspicion, and I openly acknowledge that currently it is just that at the moment, is that the real problem is with some very clever people having been very deeply confused about the notions of representation and representing.