So it's not that "'pain' does not refer to an experience", as if it might refer to something else. Rather, it's that "'pain' does not refer". At least, not in the same way that "apple" does. — Banno

So...following that principle...what does a 'painkiller' kill, metaphorically?

(Not nit-picking, by the way, just trying to follow through what you're saying).

We can “cure” some forms of color blindness or deafness and you always see the participant being shocked at the experience. I’m pretty sure you’d still get the same reaction even if the participant had a PhD in neurology. — khaled

So it is still a thought experiment then isn't it. All we have is someone who obviously doesn't know all there is to know about red and you're assuming the reaction would be the same in someone who does know all there is to know about red. That's just begging the question.

This thread has already got very far from the OP, so I'd rather not discuss it here. It's been discussed at length in https://thephilosophyforum.com/discussion/6895/what-it-is-like-to-experience-x posiibly toward about page 30.

Where oh where does the color come from? — Marchesk

Our use of language.

So if someone doesn’t understand the public concept they do not have an experience? What about children then, do they have experiences?

And could you elaborate on what the “public meaning” of red exactly is? Because I would argue that the public meaning is a reference to an experience. — khaled

The public meaning can't possibly refer to an experience, how would we ever learn what word to use if the only thing they referred to was private experiences? The public meaning is found in the use the word is put to in a particular language game. We're engaged now in just such a language game, so when I say X derives from Y I'm necessarily invoking the public concepts of both.

So the public meaning of 'red' is exactly that which gets you the apples you expect when you use it in the sentence "pass me that red apple". We learn to expect such a response by observation in a social context.

Do you still hold this position? Because it seems exactly like something I would say. Here you recognise that there is an experience X that cannot be communicated 100% accurately. — khaled

Yes. I don't think I've ever denied that our full experience at any given time may not be perfectly communicable. Though given enough time I think another person could come to know it no less well than you yourself do. Our memories are no less fallible than our language.

We certainly feel like we have some experience of "redness" when looking at a red screen — khaled

No. You have a disposition to communicate your experience in those terms post hoc. There's no evidence at all that you feel it at the time, neither from neuroscience nor phenomenologically. All you have is your dispositions to act in response to the stimuli. (Please see my response to Luke for an account, but really I've said this several times, it just doesn't seem to be getting across for some reason). If one of those responses is to reach for the word 'redness' or talk about qualia, that's no reason to draw any ontological conclusion. I could train a parrot to say 'red' every time a bell rings, doesn't mean it's having a phenomenological experience of 'red'.

Imagine your 'qualia' exist as this 'experience of redness'. What if someone implanted a false memory of this 'red quale', milliseconds after you perceiving a blue screen. How would you know? So when the evidence we do have from neuroscience suggests that there's no such event, our tendency to talk as if there was one is not good reason to deny it. We used to talk about Elan Vitale as well. Not so much anymore. Did it used to exist and now has ceased to exist? Or is it just that it's no longer used?

Wow - all that results from a public concept? — Luke

Yes. Is there some limit you had in mind to the number of things a public concept can be party to?

"phenol-thio-urea., a substance which tastes very bitter to three-fourths of humanity, and as tasteless as water to the rest. Is it bitter?" — Luke

How do you know phenol-thio-urea is a substance which tastes very bitter to three-fourths of humanity, and as tasteless as water to the rest if we don't have a public meaning for 'bitter'?

Why must it come down to a matter of ability? — Luke

Public meaning. If it weren't public concepts and our ability to detect them, then we'd have nothing to speak of and would never have learnt the term for the concept in the first place.

Sure, not if we don't see colours. — Luke

'Seeing' is a process. It starts with an external state if the world for which we usually have a public model (a red apple). It ends (arbitrarily) with our response to that external state. Colours are part of the public model of those external states which produce our responses.

Photons hit the retina, they fire a chain of neurons in the V1, these (depending on previously cemented pathways) fire a chain of other neurons (with the important backward-acting filters). Some of these neurons represent things like the word 'red', images of other things which caused the same initial V! pattern, emotions attached to either the current image, or remembered ones... All this is held in working memory, which is then re-fired (selectively) by the hippocampus. It's this re-firing which we are aware of when we introspect, not the original chain. The colour red is a public concept. We use it to indicate to other people some category of thing, we learn which word to use by experiment in early childhood (retaining those uses which work), There's nothing more to 'red' than the public use of the word.

So why does it seem like we see colours? — Luke

Because there's a public word for them. We're there no word, you'd be less likely to think you see colours. Note the differences in the colour names for different cultures. People actually claim to distinguish colour separations based on their language's colour names even when the difference in wavelengths are not as significant as colours they do not distinguish. I'm genuinely dumbfounded by the degree to which people seem to expect their introspection to deliver accurate information about their underlying mental processes. Why would it?

You have to remember we live about twelve hours in your future. It's already Friday night here, and the 'roo is currying. — Banno

Cool. Can you give me Saturday's lottery numbers as soon as you get them? I'm going to make a fortune...

Time for dinner. This is not interesting. — Banno

Yep, time to go to work. But you're having dinner at eight o'clock in the morning! You Australians are weird.

could you link it so I don’t have to rummage through 44 pages? — khaled

I meant on this site in general, not on this thread. It's mostly in the 'What's it like' discussion. We also had one on direct vs indirect realism.

I would surmise that it is because the taste exists as an experience, and it does not exist unless it is experienced by someone. Therefore, it's the way it tastes for someone, or when someone experiences it. That is, the way it tastes is the taste experience. — Luke

But this is not true. The taste doesn't exist as an experience for someone. The taste is a public concept. The experience is a unique set of memories, emotions, desires, sematic associations etc resulting from the taste.

You mean that the sensation of taste cannot have those properties only to you. That doesn't mean that it cannot have those properties to you. But neither does it mean that it has those properties to everyone. — Luke

It does have those properties to everyone who knows what taste is. The learning of those properties is what constitutes learning what taste is.

I can't possibly think one thing is 'sweet' whilst other people think a different thing is 'sweet' — Isaac


Then what of intuition pump #10? Perhaps perceptual norms affect linguistic norms? — Luke

How could they? I don't understand the process you're suggesting here.

I might be able to detect sweetness in something that other people cannot, but what sweetness is must be public. — Isaac


If it's not sweet/bitter for everybody, then maybe it's only public for some people but not for others? — Luke

It's 'sweet'/'bitter' that are public. I might think the coffee is bitter, you might think it less so, but 'bitter' is a public concept, we're both talking about the same thing. What's different is our ability to detect it in the coffee.

We learn what 'sweet' means by experiencing the use of the word in our shared world, not our private one. — Isaac


Yes, but "if we construe the grammar of the expression of sensation on the model of ‘object and name’, then the object drops out of consideration as irrelevant." So our spectra could very well be inverted without either of us noticing. — Luke

No, our spectra could not possibly be inverted. There is no neurological way this could happen. Neurons cannot represent particular colours.

You don't see a colour. Why Am I having to repeat this? You do not see a colour. There's no part of your brain which represents a particular colour. It doesn't happen, not there, absent, not present, unrepresented, lacking, missing , devoid. — Isaac


Then how do we distinguish colours? How is it that I am able to fetch a red object upon request? — Luke

Receptors in the retina send trichromous signals to the retinal basal ganglia. These are combined in the V1 area of the occipital cortex to form signals responsive to combinations of wavelengths, different combinations will (normally) fire different neurons (or fuzzy combinations fire clusters of neurons - we're not sure yet). These start two chain reaction processes - one along the dorsal pathway, and one along the ventral pathway. The former leads toward responses, the latter toward recall. All along the signals are suppressed by regions higher in the chain to minimise surprise signals. Eventually such chains will reach a response (fetching the red apple) and a recall (other things which are red apples from your memory), as well as emotions, desires etc.

That's what 'a red apple' means. adding 'what we call...' to it implies that there might actually be a red apple other than what we call one. — khaled

I've written extensively here about model-dependant realism. I don't think there's anyone wants to go through all that again.

I seriously doubt it. — Olivier5

An interesting thesis. So for your first port of call I recommend the Manchester undergrad course

https://www.manchester.ac.uk/study/undergraduate/courses/2021/00550/bsc-cognitive-neuroscience-and-psychology/

Then there's some really good masters work there, but also at UCL

https://www.ucl.ac.uk/pals/study/masters/msc-cognitive-neuroscience

The most exiting place to do doctoral and post doc work is the lab at Sussex

https://www.sussex.ac.uk/research/centres/sussex-neuroscience/research/consciousness

Hopefully they'll have some research opportunities for you.

When you've finished all that, it would be great if you could report back on your findings, in the meantime...perhaps just look up some actual source material before regaling us with how you 'reckon' the brain works?

↪Isaac

That's rather the point at issue. — Banno — khaled

It's not at issue. We don't just make up neuroscience to have a discussion about it. There is no part of your brain which shows you a colour, it cannot happen, brains are made up of neurons, not colours.

I don’t think many would answer that but if that’s your answer then I see why you’d say qualia don’t exist. Seems nonsensical to me to say that if I’m literally forced to lie about the color I’m seeing that I’m actually seeing the color that is the lie. — khaled

You don't see a colour in your brain. Why Am I having to repeat this? You do not see a colour. There's no part of your brain which represents a particular colour. It doesn't happen, not there, absent, not present, unrepresented, lacking, missing, devoid.

Yes. A red apple. — Isaac


More accurately “what we all call a red apple”. Public meaning and all that. — khaled

That's what 'a red apple' means. adding 'what we call...' to it implies that there might actually be a red apple other than what we call one.

If you ask people to pass you the red apple, do you generally find they pass you the one you were expecting? — Isaac


Correct. That is no evidence to indicate they have the same experience when holding the red apple as I do when I hold it. — khaled

I doubt they do. As I said, people's response to the red apple will vary. Their response to the colour is not the colour.

Say I was wearing glasses that inverted all the color going into my eye. — khaled

Colour doesn't go into your eye. Photons go into your eye. Colour is a public concept.

So in this previous example I just said, am I still seeing a red apple with those devices on? Even though the light coming into my eye is inverted? — khaled

Yes.

I definitely see something when looking at a red apple. — khaled

Yes. A red apple.

I do not know if you see the same thing. — khaled

If you ask people to pass you the red apple, do you generally find they pass you the one you were expecting?

Maybe what you’re seeing I would describe as “blue”. — khaled

How? We're you taught to use the word 'blue' incorrectly?

Correct. Does this imply that we are experiencing the same thing when looking at the apple? — khaled

Yes. We're experiencing the apple. As I said, our response to the colour of the apple will be different, but this is what our experience actually consists of, it's not the subject matter of our experience (that's the apple) it is the constitution of it.

And then conceded that the intent behind the expression is as I described. I’m not proposing a neurological theory here, I’m saying what the intent behind the expression “the apple is red” is — khaled

The intent is that the apple corresponds to the public meaning of 'red'. Anything less and the expression is useless.

If an apple has a taste, then there is a way it tastes. Am I Englishing wrong? — Luke

No, just inventing an extra entity without any apparent reason. The apple has a taste - two ontological commitments, that there is an apple, and that it has a taste. Why the third, that in addition to there being an apple and there being it's taste, there is also 'the way' it tastes?

If apples have a taste then you can taste them (or not), which means they taste some way to you. I’m not suggesting it becomes some other thing in your mind, but it becomes something in your mind: a sensation of taste. That sensation of taste probably has properties, such as sweet, bitter, juicy, sharp, etc. — Luke

Nope. The sensation of taste cannot have those properties to me because those are public words, those properties have public meanings. I can't possibly think one thing is 'sweet' whilst other people think a different thing is 'sweet', otherwise there's no public meaning of 'sweet' for us to use and the word ceases to have any function. I might be able to detect sweetness in something that other people cannot, but what sweetness is must be public. We learn what 'sweet' means by experiencing the use of the word in our shared world, not our private one.

When people say “The apple is red” they do not really care about what color gets imagined in your head. — khaled

This is why I went to all the effort of explaining the neurological process.

No colour gets imagined in your head.

End of story. It simply doesn't happen. You do not have a bit of your brain which lights up red for another bit of your brain to see. You do not have a bit of your brain which represents 'red' that is distinguishable in any way from the bit of your brain which represents 'green'. It just doesn't happen. I don't know how much more clear I can be about this, you can't just make up neuroscience to suit your preferred view of the world.

___

There is the colour of the apple - that is a public property it has, a shared fiction (I'm a model-dependant realist). It's the colour we call red, the colour of stop lights, the colour that the grocer reaches for when I ask for red apples.

Then there is our response to the colour of the apple - different for different people. Memories, emotions, desires, connections, associated words... all of this is unique to the individual and unique to the very moment, but none of it is the colour of the apple. All of it can be observed in one way or another - it's not radically private.

And - what's more important - all of it is in constant flux at a speed faster than our working memory can retain (again, this is not really up for debate). So not even we are aware of what all these responses are, we're only aware of the story we later tell about what all these responses were.

Then - all of it actually feeds back to our sensory inputs (again, in constant flux) to mediate and filter what we 'sense' to make it more suit the story, much of this story is influenced by the public meaning of 'red'.

What's completely absent throughout this process is any identifiable step at which there is a sensation, unique to the individual, which can be identified as a particular colour. There's no neurological evidence for it, there's no phenomenological evidence for it, there's no sematic evidence for it. I've really no idea why this concept continues.

You think that the word “qualia” has an intentionally nonsensical meaning? — Luke

To an extent yes. A lot of people hang a lot of their professional respect on being expert in matters which would take too long (and too much risk of error) to learn the physical basis of. There's a strong incentive to create entities whose properties are sufficiently ineffable that one can forever be right about them without fear of redundancy.

Why does it need to be considered as an “intermediary” instead of just the (quality of the) experience that a person has? — Luke

What is the difference between the quality of the experience and the experience?

The way things taste, look, sound, feel to a particular person. — Luke

What is 'the way' doing here?. The taste of an apple is the taste of an apple, there's no other thing it becomes inside my mind. There's the chemicals which make it up, there's the responses those chemicals cause (both in neurological terms, if you're a neuroscientist, and in stated cultural terms for the rest of us). Where in that is qualia? It's not that I spit out the bitter coffee, it's not that my neurons fire in a certain way, it's not that I reach for the word 'bitter' when describing it, it's not that I'm reminded of my grandma's coffee...because none of these things require a new non-physical entity. The synaesthete reaches for a different word, has different memories, has different mental images... none of these issues requies a new entity either. So wither qualia?

“qualia” isn’t one of those words. — Luke

But that's just begging the question. We're arguing about just that very proposition.

They inevitably end up doubting really obvious stuff like their own consciousness — RogueAI

What is so difficult to grasp about the fact that what seems obvious to you is not obvious to others? Are you suggesting that 'obviousness' is some kind of objective property of posited entities?

I meant that we cannot pick out precisely determinate features of our inner lives to share, as we can with perceptible objects. — Janus

Yeah, maybe. Then i suppose those we must show, or pass over in silence.

I guess we don't even need to speak about quality of experience, but just about the experience itself. — Janus

Spot on. There seems no purpose for this wierd intermediary 'qualia', neither in perception, nor in experience. What we can say we can say directly of the world itself, what we cannot say...we cannot say.

But if we all think we enjoy an inner life, then even though we cannot directly share our inner lives in the way we can directly share the sensory world, could it not be sensical to talk about our inner lives — Janus

Wouldn't talking about our inner lives count as sharing them? Otherwise how would we select the words which might constitute such a conversation if there were no public meanings to which they might refer?

why aren’t all language games sensical? — Luke

I had https://en.m.wikipedia.org/wiki/Nonsense_verse in mind. Maybe you're using a stricter meaning of sensical than I, but I don't think the subject matter of nonsense poetry is suitable for serious discussion, even if the existence of nonsense poetry is.

Good. Then you should accept that it’s not senseless to talk about qualia or inverted spectra. — Luke

Why? Are all language games sensical?

Because the Hard Problem hasn't been solved. Ergo, the book you linked doesn't solve it. — RogueAI

Who judges whether it's been solved or not? You? Chalmers?...

I don't think neuroscience is going to solve the hard problem. The idea that you can mix non-conscious stuff around in a certain way and add some electricity to it and get consciousness from it is magical thinking. — RogueAI

Why? Without having studied the properties and functions of all non-conscious stuff, how are you in a position to say what it can and cannot produce?

Since we know consciousness exists — RogueAI

We do?

we should doubt the non-conscious stuff exists. We have no evidence that it does anyway. Why assume it exists? — RogueAI

If non-conscious stuff doesn't exist then how can you conceive of a problem with it's producing consciousness? How have you aquired some rules regarding what this non-conscious stuff can and cannot do if it doesn't even exist?

You are confusing the easy problem (neural correlates of mental states) with the Hard Problem (how does non-conscious stuff produce conscious experience). Chalmer's paper is a great place to start. This is also good: https://iep.utm.edu/hard-con/ — RogueAI

How do you know that the work I've linked doesn't tell you how non-conscious stuff produces conscious experience?

Look, the means by which this non-conscious stuff produces consciousness must, if it exists, be some process or mechanism that is a property of this non-conscious suff. It just seems really odd to me that you'd claim interest in such a mechanism and then refuse a study of the exact non-conscious stuff you would need to know about in order to ascertain if the production of consciousness was among their feasible properties.

Was I asking what Chalmer's thought about consciousness?

If we're making astonishing progress, shouldn't somebody have seen something that points the way to a mechanism by now? — RogueAI

https://www.sciencedirect.com/book/9780128005385/neuroscience-of-pain-stress-and-emotion

How does the feeling of pain emerge from non-thinking/feeling stuff? — RogueAI

Your position is easier to resolve than Oliver's.

https://www.sciencedirect.com/book/9780128005385/neuroscience-of-pain-stress-and-emotion

An interesting thesis. So for your first port of call I recommend the Manchester undergrad course

https://www.manchester.ac.uk/study/undergraduate/courses/2021/00550/bsc-cognitive-neuroscience-and-psychology/

Then there's some really good masters work there, but also at UCL

https://www.ucl.ac.uk/pals/study/masters/msc-cognitive-neuroscience

The most exiting place to do doctoral and post doc work is the lab at Sussex

https://www.sussex.ac.uk/research/centres/sussex-neuroscience/research/consciousness

Hopefully they'll have some research opportunities for you.

When you've finished all that, it would be great if you could report back on your findings, in the meantime...perhaps just look up some actual source material before regaling us with how you 'reckon' the brain works?

You’re the only one bringing up any belief about being able to predict the future perfectly. That’s not anything I’m talking about at all. — Pfhorrest

Except that...

I’m saying that if you see something and think “whoa a black swan, I didn’t think those were possible...” — Pfhorrest

is exactly that, a prediction about the future - that there would be no observations of black swans in it.

If instead you see the same thing and think “oh look, somebody painted that swan black...” then you don’t have to revise any beliefs because a fake black swan is what your background beliefs initially lead you to perceive and that doesn’t contradict any other beliefs such as that all swans are white. — Pfhorrest

Again, you're ignoring the effect of states of uncertainty. I know you keep saying that you've included uncertainty by attaching the word 'probably' to your original theses, but tacking on the word 'probably' doesn't even begin to address the complexities of adding probability and uncertainty (or it's opposite) to the understanding of beliefs. What I think just about every other person involved in this thread is trying to tell you (in one way or another) is that situations where we are in no doubt (such as @Banno is pointing out), and how we resolve uncertainty when we are in doubt (such as @Janus and @Srap Tasmaner are discussing), are key to understanding beliefs.

You treat them as if we can innumerate and resolve them one at a time (again, despite your protestations to the contrary, you keep coming back to simple examples as if they encapsulated a principle which applied more widely). In the situation regarding the observation of a black swan - if you isolate the observer from all social connections, all linguistics, all embodiment and all cognitive context - it may just be the case that he would simply choose between the two options you describe. But there are no such people, and in reality the situation is vastly more complex to a point where this simple algorithm is next to useless.

...Not that it matters now, but

I’m saying that if P(A) is small and P(B) is small then P(A)*P(B) is small. “P(A)*P(B)” is the probabilistic equivalent of “A and B” in the same way that “P(A|B)” is the probabilistic equivalent of “A if B”. — Pfhorrest

...is exactly what I said you were doing (incorrectly), so that paragraph shouldn't start with "No", it should start with "Yes" followed by an explanation of why you're doing that when A and B are not independent variables and you were supposed to be explaining how such matters were resolved using Bayes.

Links to fascinating studies answering this too:

Start with an ape? In what situation might it have the brain shivers that you would describe as having a mental image and I would describe as readying to select among pictures? — bongo fury


Still, the mental images (whatever we call them or construe them as) aren't traces, or recordings. — bongo fury

I'm not sure what you might mean by the difference. It's obviously a really complex subject, but a 'mental image' from memory consists of almost exactly the same neural activity as the image in front of you right now. They are fired in a different order and from different sources, but it's the same neurons. so, you might see a table and that would result from neurons for edges, colour, texture etc all coming together with contextual areas such as the room you're in the activity you're doing, (and hundreds of others, it can't be overstressed how complex this really is) to fire the neuron for 'table' (or more likely specifically for 'my kitchen table'). This then goes on to fire areas which respond to this (those that search for the word 'table', those that prepare you to put your cup on it...). All of which is linked together by neurons in the hippocampus so that they can fire simultaneously the next time one element is fired. What's happening in memory recall is that those neurons are being fired in the reverse order. One element fires (the cause of recollection, maybe the word 'table') and the neuron in the hippocampus then fires all the others so that your brain is put in the same state as if it had seen the table.

I think what throws a lot of people about this 'same state' idea is the way memories seem more vague and malleable. This is caused by two things - the number of links the hippocampus drew together in forming the memory (it may have missed elements which were there), but much much more importantly than that is the constant re-appraisal that 'live' images undergo in perception. It's not the inaccuracy of the 'snapshot' that's being misunderstood here, it's the inaccuracy of the exact same moment of actual live perception. Any given instant of immediate perception is no less vague and malleable than that same instant of recollected perception. It's just that with immediate perception, the very millisecond in which the doubt arises about a section of an image, it can be resolved with a saccade focussing on reducing uncertainty there. We do the same with mental images (the eyes actually move around the mental image), but we have less data with which to resolve uncertainty. One of the theories about REM sleep is that the eyes are constantly trying to resolve the uncertainty in the flurry of mental images produced in the dream state.

(The above is all extremely speculative - the science is still uncertain in many areas)

All of which is to say that recall is basically the same as the initial perception, just limited by an inability to reduce uncertainty with focussed data hunting. Whether you want to call perception a 'mental image' or not, is moot, but if you do, then recall is probably one too.

As to apes...I don't really keep a stock of animal cognition papers, only one or two that cross over with stuff I'm interested in, but I know that work was done on macaques showing the same image recognition from memory using the same processes that human subject showed.

As for the 'physical trace', I'm happy to leave that to science. There's a growing body of evidence on the topic...@Isaac? — Banno

Indeed (see above). Growing, but still inconclusive as yet. It think the jury's out on the single-neuron vs neural-system theories, but, as Stephen Kosslyn put it

At this juncture, it is clear that the bulk of the evidence supports the claim that visual mental imagery not only draws on many of the same mechanisms used in visual perception, but also that topographically organised early visual areas play a functional role in some types of imagery.

Or, as I say, persuade me otherwise, by better describing a typical occasion on which an animal recalls a scene to mind. — bongo fury

https://pubmed.ncbi.nlm.nih.gov/29754898/

But I wasn't so much interested in persuading you, that seems a Sisyphean task (not you personally, just in general), I was just interested in why you would hold such a presumption in the absence of any evidence either way. People's assumptions intrigue me.

So you were not surprised by the apparently purple swan, and it was consistent with your prior beliefs? Then you have no contradictory observations to falsify anything. You just saw something consistent with your expectations. — Pfhorrest

Surprise has nothing to do with it. I might be surprised by a purple swan because I wasn't expecting one. This is the part about time-dependant beliefs I mentioned earlier. I don't believe I can predict the future, yet things still surprise me about it. I have expectations about future events despite not believing that I can predict them accurately. I believe the set of observations which seem to me to be accurate up to this very moment in time, but I cannot believe now those that I will see in future.

This is where probabilistic belief becomes crucially important to our understanding of belief. I believe almost nothing 100%, I believe different things with different strengths. The strength with which I believe future events is inevitably altered as the time becomes the past, again no-one doesn't already believe this.

Neither confirmationists, nor fideists, nor nihilists, nor any of your stated targets believe they can predict the future with 100% percent accuracy. So none of them are disproven by your statement that observing something surprising contradicts a belief (an expectation) that we wouldn't.

I never said it was. I say that the probabilistic equivalent of a conditional statement is a conditional probability: the probabilistic equivalent of "B if A" is "P(B|A)". (I did misleadingly say that "P(B|A)" was equivalent to "P(B if A)", but that was for a natural-language reading of "B if A", and that equivalency is only problematic when "B if A" is taken as a strict material implication). — Pfhorrest

Your claim above is

This still accords with Bayesian reasoning, because you could reason along the same lines, but probabilistically instead of in those absolute statements. If the thing you're observing is very likely to be a real purple swan given your background beliefs, and yet it's very likely that all swans are white given what you believe about swans, then what you're observing must be very improbable. — Pfhorrest

So let A be "the thing you're observing is very likely to be a real purple swan given your background beliefs" and B be "all swans are white given what you believe about swans". You're saying that the probability of A and B ("then what you're observing must be very improbable") is P(A and B), but it is not - under Bayes - it's P(A|B) which is a different calculation.

I doubt that we ourselves do it before we grasp the reference of words and pictures.

I'm open to persuasion though. — bongo fury

The persuasion is not the interesting thing here though, it's the doubt. What would possess you to have such a doubt?

This still accords with Bayesian reasoning, because you could reason along the same lines, but probabilistically instead of in those absolute statements. If the thing you're observing is very likely to be a real purple swan given your background beliefs, and yet it's very likely that all swans are white given what you believe about swans, then what you're observing must be very improbable — Pfhorrest

...which equates to your error above (not that this hasn't already been pointed out). P(A|B) is not the same as P(A and B). You're misunderstanding Bayesian probability - which is fine if what you're doing is inquiring, but when you're declaring some theory to be consistent with it you really ought to do more than just glance at a Wiki page on the topic.

Other way around: you change the beliefs which initially lead you to construe your experience as genuinely seeing a real purple swan, if you instead conclude that you must have been deceived. — Pfhorrest

Which beliefs? I never believed that all my observations are accurate and unambiguous. What I believed prior to seeing the purple swan was that some observations turn out to be true and others don't.

It's in that sense that although we can never be sure any particular set of beliefs is the correct, we can be sure that some particular set of beliefs is an incorrect one, if e.g. that particular set of beliefs says both that all swans are white and that the thing we're seeing right now is a purple swan. We can't be sure which of those (or which part of which of them) is incorrect, but we can be sure that the world definitely isn't exactly like that, it's different than we thought in some way or another. — Pfhorrest

So what belief has been falsified here? Not the belief that there are only white swans. Not the belief that I haven't seen any purple swans (I'm presuming I was deceived). Not the belief that my observations are always accurate and unambiguous (I never believed that). Not the belief that I haven't ever seen anything which even looks like a purple swan (That belief was true at the time - all time-dependent beliefs change as time changes - I've never seen 7:45 on the 20th November 2020...until now).

So exactly what belief has now been falsified which anyone ever actually had prior to this observation?