Technically people don't get the virus directly from another person (unless maybe they were french kissing and they swap spit), they get the virus from being in a contaminated environment, as illustrated in the analogy as being the tacks on the highway. — Roger Gregoire

But that's irrelevant. The only way your contaminated environment can get contaminated is by putting viruses into that environment, and that requires the viruses to exist. Viruses are only made by virus factories, and whereas viruses don't reproduce on their own, the only type of virus factory is a carrier. Whether Fred swapped spit or got infected from a contaminated environment is irrelevant.

2. Cars with good tire tread crush tacks (kill covid virus) and get stronger when on the highway (out in society). — Roger Gregoire

A C1 person isn't "stronger", they're just immune to this specific virus. Immunity of this type works by a lock and key mechanism; an immune system recognizes a specific threat it was formerly exposed to, and can attack that threat. Consider Joe, a local, who is immune to hundreds of local diseases. And consider John, a regular traveller, who is immune to thousands of tropical diseases. Joe is in state C1, because he was previously exposed and recovered. John is in state A, because he just happened to avoid this virus. Then presumably John is "stronger" than Joe, because his immune has thousands of keys, but that does not offer him any advantage against this virus. Joe is "weaker"; his immune system only has hundreds of keys, but one of those keys fits this virus's lock. But John can still get infected; Joe cannot. So it's not about "stronger" and "weaker"; it is simply about having or not having this key.

State B - All cars can be infected with tacks, if exposed to tacks on the highway. — Roger Gregoire

Your analogy is horrible. Imagine that I have viruses everywhere on my feet and hands, and all over my clothes; i.e., my car has tacks all over it. I take off my clothes and wash them, wash my hands and feet, and in this scenario just happen to not get infected. Then I'm never in state B. The fact that the virus was all over my body is irrelevant; since I'm never infected by them, those viruses may as well be in China.

So, no, that's not a good image of what State B is at all. State B is infection; infection is when the tacks convert your car into a tack factory; infected cars produce tacks by the truckload, and leak them everywhere they go. Immune cars are those that have keys in them to disable the tacks lock. And your car being a tack factory requires that none of the keys inside the car fits the lock that is the tack. And just to be crystal clear, the degree to which talking about tack-locks converting cars without the fitting tack-key into tack factories that leak out the tacks sounds like a silly mental image, is precisely the degree to which your analogy is misleading.

1. Vulnerable people die from covid
2. Healthy people gain immunity from covid.
3. Herd immunity: the more healthy immune people out in society creates a greater protective effect to the vulnerable (i.e. the less deaths of vulnerable people). — Roger Gregoire

So here I've underlined something... presumably this is the goal.

For discussion purposes only, I'll oversimplify. Let's say everyone is either healthy, or vulnerable. I'll grant 1 and 2 literally; vulnerable people who get sick die, and healthy people who get sick become immune. Unstated, for simplicity, let's presume that everyone who is vaccinated becomes immune.

But here's how the mechanics work. Everyone starts out uninfected, call that state (A). They can become infected, state (B), if exposed to a carrier. A carrier is essentially another person in state (B). Then if the person is healthy, they go to state (C1), immune. If they are vulnerable, they go to state (C2), dead. So in these terms we want to minimize the number of people in state (C2), death by covid.

So let's talk about vulnerable, living people; by the stated goal these are who we're protecting. They are in state (A). If said people get to state (B), chalk it up in the lost column. That having been said, vulnerable people get to state (B) by being exposed to carriers... other people in state (B). It doesn't matter if the carrier is healthy or vulnerable; infection is infection is infection.

Now, we've granted that healthy carriers eventually become immune; (B->C1). But by comparison, vulnerable carriers eventually die; (B->C2). In either case, the carrier state is transitory. But the carrier state is the sole risk to the vulnerable; the only way for (C2) to happen is for vulnerable people to get infected, (A->B), and that only happens via exposure to a carrier in state (B). So I cannot emphasize this enough, but if your goal is to minimize death by covid (C2), that is entirely equivalent to minimizing exposure to carriers (exposure to people in state B).

This is not correct. We can achieve herd immunity through infection, vaccination, and/or the combination of both. — Roger Gregoire

But that's a false comparison. A healthy person can only lead to a vulnerable person dying by becoming a vector, and the only way that happens is by infection; A->B->C1. That the person winds up immune is inconsequential; the entire risk is that person being in state B for any time at all. By contrast, vaccination takes a healthy person from state A directly to C1, bypassing state B. Since the only possible risk factor is being in state B, and that only happens via infection, you're comparing the only possible way that a healthy person could cause another to die to a process that makes that impossible.

@TiredThinker

So i'll read TiredThinker as saying that they do not see into other parts of the spectrum, hidden from us muggles, but are capable of greater nuance over the same colour range. — Banno

Okay, but that would be wrong too. We have tests for deuteranopia (a particular form of "anomalous dichromacy") that don't involve slicing somebody's eye apart and putting it under a microscope... the common ones just have a bunch of dots with some symbols like numbers displayed in them in a "different color".

And yet, a deuteranope can see the entire rainbow just like we can; it's not like deuteranopes see holes in the rainbow or the same colors repeating in it. So to extend this as an analogy, were humans all (perceptual) tetrachromats, they should be able to design similar tests for what would be "anomalous trichromacy".

Tetrachromats do see into other "parts" of the spectrum, hidden from us muggles, because neither trichromats nor tetrachromats are seeing the spectra; what they are able to distinguish is baked into the name. Tetrachromats are seeing a "4-sampling" of the spectra and trichromats a "3-sampling". Contrast this with how our hearing works... we can not only hear different pitches, but we can make out the individual notes being played in a C major chord and, likewise, can still pick the individual notes out if this chord is walked up and down the scale. But hearing is mediated by a sampling across the entire "aural spectrum"; the frequency components in sounds map to specific locations in our cochlea, and we sense the sound made at each location. Our aural senses actually do seem to "care" about the frequency as well; a higher pitched sound sounds higher. Mind you, there's a perceptual limit to how this works (we can't make out the individual "notes" being played in pink noise), but the apparatus is there to distinguish frequencies. Color is very much not like this; our hue perception forms a circle (not a scale) with spots in it along the violet portion that don't correspond to pure frequencies; and whereas along this circle some colors look blended, it's not in a way that maps to the "individual notes" in the spectrum analogous to how the C major chord sounds... we might see components in orange, for example, but the orange your RGB monitor renders doesn't look drastically different than a monochromatic orange.

They can't see a factor of 100 more colors than trichromic without literally that many more cones. — TiredThinker

This sounds suspicious to me. Why would the number of distinguishable colors be a linear function of total cone counts? (Incidentally our cone counts are asymmetric; roughly we have on the order of 3.5 million L cones, 2.5 million M cones, and 0.5 million S cones... the distribution along our retina is asymmetric as well).

odd, that folk seem to think explaining the physiology answers the question... — Banno

Not sure what you mean:

"Red" is part of a language game played by a community. — Banno

...but how do you play this game?

I was wondering if the perception of color is as defined as the wavelengths that produce it? — TiredThinker

Humans generally have three cone types and see colors under well lit conditions. The primary bio-physical layer is established by photopsins, which are light sensing proteins. Each photopsin has a particular probability of absorbing each photon that goes by; this probability changes as a function of frequency and the photopsin. When absorbed the photopsin folds (isomerizes), releasing a chemical that begins a chain reaction leading to your cone signals. There are three photopsins involved here; erythrolabe, chlorolabe, and cyanolabe. Since they either fold or not, and each is sensitive to a broad range of frequencies (just by different amounts), the eye isn't really measuring wavelengths; the best way to describe what this is a measure of is simply to point to the photopsins... it's a three dimensional measure of three kinds of photopsins folding.

A lot of stuff happens from here to your brain, but fast forwarding through all of this, at the other end (in the brain) there are more adjustments made to color, as made evident by the subjective perceptual properties of optical illusions of color. The main categories of such adjustments seem to have to do with color being a virtual property of objects. Specifically, color adjustments seem to be consistent with the effects that shadows and lighting have on the "eye color" (the three-dimensional measure cited above). To speak loosely at an intuitive level (invoking a pseudo-teleology), it's a misnomer that the color visual system is attempting to reconstruct wavelengths, or model the wavelengths of light. Our color visual system apparently does not care one iota what the wavelengths really are, and why should it? What our visual system seems to focus on, instead, is recognizing and distinguishing objects. If the same object projects a different one of those three-dimensional values mentioned in the first paragraph, your brain tries to "fix" it by calculating a virtual invariant that particular objects should have particular colors.

I see that you still have no clear idea what my argument is — A Raybould

Perhaps, but, 25 days ago. you responded specifically to this:

"... but to simply conclude that the color experiences are the same because we're all human sounds to me more like guesswork. — InPitzotl" — A Raybould

...with this:

It doesn't approach being a proof, but, IMHO, it is a plausible hypothesis. Per my earlier post, I would not propose that everyone's experience is the same in detail, but that for most people, there is a broad degree of functional equivalence. — A Raybould

largely, it seems, as a result of your attempts to paraphrase it into something that you can dispute. — A Raybould

So while you're speculating, is that because you're inexplicably the most important person in the world to me, or can you explain why my post count isn't a lot higher than it is given I'm just out to dispute people at random? (E.g., note that all this time, I haven't intervened on either side with your discussions with jkg20... isn't that curious?) Also, why do you feel the need to share your ridiculous speculations about my motivations with me, who one would think would be in a much better place to know said motivations?

Allow me to speculate about my own motivations to you... it's... perhaps... because 25 days ago you responded to the aforementioned quote with the aforementioned response, to me, and that you seem to be under the mistaken impression that this somehow should change my view about the thing I said that you quoted. Also, if you haven't guessed, color per se is a personal passion of mine. (Now doesn't that sound a lot more viable than he's-out-to-get-me [<-being literally some random guy on the internet]?)

So my issue with you is your alleged defense of this being "plausible" above the level of being "guesswork".

I will reply with a lot more detail — A Raybould

I'm sure you will.

It goes back to your attempt to claim that the possibility of behaviorally-invariant inverted spectra somehow invalidated my hypothesis, — A Raybould

Stop right here. No. The possibility does not invalidate your hypothesis; that's not the point of it. Your hypothesis is inadequately justified. The possibilities simply highlight ways in which you can be wrong that you haven't actually addressed.

(FYI, your confusion of my rejection that your argument is adequate justification with invalidation of your hypothesis suggests the possibility that you're potentially susceptible to argument from fallacy, so I'd like to just point that out quickly).

We disagree, apparently, on how plausible it is. — A Raybould

We disagree over how well your justification supports your hypothesis.

Let me suggest a device... call it the surprise test. Your hypothesis suggests we see the same colors. Your support is that evolution basically just rolls that way. Let's just suppose someone proves your hypothesis wrong. Based on your presented hypothesis, and the support you've given for it, how surprised should I be to find it wrong?

I feel that you have not yet made the case that a third party should summarily dismiss this hypothesis. — A Raybould

Wrong criteria. "Adequately justified" is the phrase I've used, in multiple posts. It's not about dismissal, it's about the criteria for acceptance. So apply the surprise test. I feel you have not yet made a case sufficient for a third party to find it surprising, based on the case you've made, to find the hypothesis wrong.

This section shows that, as a matter of fact, undetectable inverted spectra cases are sparse among all possibilities, and an explanation of why they are does not, of course, dispute the fact that they are. — A Raybould

Just to clarify, section 2 is talking about behaviorally undetectable inverted spectra, not undetectable inverted spectra. They're talking about different things that the guy with inverted spectra might do. If you can analyze his brain and find different representations of color, that's not what they mean.

Also, opponent color theory is mainstream (at least among color theorists). The analysis in section 2 of the SEP article didn't take into account the effects of color opponency on the modes of asymmetries they were discussing. Opponent color analysis is presumed to occur in the ganglia cells in the retina (cones connect to bipolar cells which connect to ganglia).

I had regarded your focus on L2 as just a case of unnecessary specificity, but when I looked for something justifying this specificity, I did not find any use of L1/L2 terminology with regard to color perception and experience - perhaps you can provide some references, and explain the relevance of your specificity? — A Raybould

I hope you didn't search too hard, because the terms L0, L1, and L2 are simply defined by me in this thread for your specific benefit, for the purpose of this discussion, in this post.

Refer to this picture again:

L0 is spectral. This is the physical form of colors; objects reflect different frequencies of light by different amounts.

L1 is colorimetric:

It is similar to spectrophotometry, but is distinguished by its interest in reducing spectra to the physical correlates of color perception, most often the CIE 1931 XYZ color space tristimulus values and related quantities. — Colorimetry

Colorimetry is based roughly on Grassmann's laws. L1 colors in short then are produced by our three cones under photopic conditions, and result from our trichromaticity. This collapses the full visible spectrum (L0) into three distinct cone channels. There is also the opponent color process, which is triggered primarily by processes in the eye (namely, ganglia cells that connect the signals from the cones, lying behind bipolar cells); so I'm lumping this into L1 (from a colorimetric perspective, opponent processes don't change anything; a spectral metamer is still that metamer and therefore still the same point in a colorimetric space). L1 colors are critical for experiences, because everything gates through them... if a person's eye cannot distinguish one metamer from another, then neither can his brain, and neither can he. But it's pretty out there to speculate that eyeballs experience color.

L2 is experiential. Experience is not produced in the eyeball; it's produced in the brain. Various places in your brain (visual cortex) are responsible for color analysis; here's an outline:
https://en.wikipedia.org/wiki/Colour_centre
...which I post as a raw link for emphasis (you really should read at least the first paragraph). Per a physicalist account, at some point, something in your brain generates consciousness, and your personhood arises. Within your mental scape, you experience colors, such as the colors in the color illusion displayed in this diagram. Since mind states are brain states, your experience should have a correlate. Those are L2 colors. Qualia are experiences:

Those new to the topic should first read the entry on qualia. ... Qualia (singular ‘quale’), in a common modern usage, are properties of experiences that type them in phenomenological respects. — Inverted Qualia

...and as such, inverted qualia are experiences. So qualia, as in the things being inverted in qualia inversion, are at L2, not at L1.

More substantively, it is completely unclear to me why my hypothesis requires a BM gene of any sort. — A Raybould

Oh that's easy... that falls out pretty much directly from this:

The "learned lessons" are evolutionary adaptations. — A Raybould

Let me just point out here that if this name-the-gene standard of whatever-it-is-that-my-hypothesis-does-not-meet is applied consistently, then a good deal of evolutionary and general biological theory, including the fundamental one that life as we see it today is a result of natural selection, must be thrown out. — A Raybould

Well, then I am not putting anything at risk by not responding until it is more than just creationists who are making that claim. — A Raybould

What are you talking about? These genes are just portions of a molecule, and they encode photopsins. Photopsins photoisomerize (fold in response to light), and this leads to the chain reaction that causes the cones to send signals. Change the shape of the photopsin and you change the absorption characteristics. For example, L and M's sensitivity curves are close, because erythrolabe and cyanolabe are chemically close, because the encodings for them on the associated genes encode for those particular close molecules.

Evolution doesn't hang in the balance, and if I suddenly managed to become a creationist, someone forgot to inform me. I've no idea where this nonsense came from... did you perhaps think those genes coded for color percepts?

ETA: Ah, it occurred to me that this nonsense may be due to you not understanding the question I asked you. You're proposing that same-experience in particular is selected due to it being an evolutionary adaptation. I'm asking you, why you think same-experience is subject to evolutionary pressures, which in my mind equates to the core of your hypothesis. But I'm guessing you're interpreting that as questioning evolution. Evolutionary adaptation is a process where selective pressures (what you're adapting to) influence the frequency of genes (in "competition" for genomic representation; i.e., alleles) in a gene pool (the change in allele frequency being evolution) to the degree that adaptive gene variants become predominant in a population. Your hypothesis presumes that same experience is adaptive, which further presumes that different experience would be maladaptive, which in turn means that there's a distinction between same experience and different experiences sufficient to warrant a distinction between an adaptive and a maladaptive behavior, in the sense that having same experiences of some particular sort somehow winds up increasing the probability that genes remain in the gene pool (e.g., more women with this trait survive to give birth; more men survive to mate; women give birth to more offspring; women find mates more easily, and so on). All of these are presumptions that basically equate to your core hypothesis, but you seem to argue for none of them, because you seem to think simply invoking the word "evolution" is enough to support your hypothesis. That's not true. Evolution only supports your hypothesis if it supports your hypothesis. For same experience to even be adaptive in the first place, it has to influence something that selective pressures can work on.

You have supplied no adequate reasoning as for why this would be the case; effectively, you just presumed it. (Mind you, you did attempt it, by pointing out someone else's argument in section 2 of that SEP article regarding asymmetries of perception, but since that can be explained in terms of L1 properties it's not quite adequate; note that I actually granted relevance to that argument, but have specific technical reasons to require more details). That is precisely what I'm calling guessing, and what I'm demanding you need to do before you can call your hypothesis adequately justified. If you cannot justify why same experience would be selected, you ipso facto have not justified that it is. So long as there's a giant presumptive gap in your argument, it does not rise to the level of adequacy.

What do you actually mean by “A is right for Joe”? ... The first position is relativist, — Congau

The point here being to complete your argument, so pick the one that makes your argument least complete.

Objectivism is not about reaching a common agreement. — Congau

Correct; from the link in the OP (i.e., the wiki page):

Moral universalism (also called moral objectivism) is the meta-ethical position that some system of ethics, or a universal ethic, applies universally, that is, for "all similarly situated individuals" — Moral_universalism

The main point for an objectivist (and I hope and think most of us are objectivists) is that nothing is ever right just because someone thinks it is right. — Congau

Okay, but we can still devise a moral meta-ethic where some things are objectively wrong and others are relatively wrong, and such would avoid the issue by your metric of not being a moral system but can still hold that some things are indeed right just because someone thinks it right. What I'm really interested in is your argument against those positions.

You're making a conflation. — RogueAI

No my friend, you are.

You have a word in mind (call it "sound1") which refers simply to vibrations in the air.

Sure. But the fact that InPitzotl is using the word sound1 to describe what the invisible stuff around Bob and Sheila do has no bearing on Bob or Sheila.

The people from long ago don't have that word because they don't know even know air can vibrate.

Sure. But that's the point. Bob and Sheila not only don't know sound1; they don't have to to talk about sound1 states. All they have to do to meaningfully talk about sound1 states is know that there are states, and be able to distinguish them. Bob and Sheila have a different, more vague theory:

When they talk about sound, they're using their word (call it "sound2") which refers simply to what they're hearing, which is why hearing is so important.

...of sound2. They just hear stuff. So, sure.

But Bob and Sheila recognize that there's a "thing" they are hearing... a state in the world such that if it's of moderate volume and a person isn't deaf and is in the same area, the other person would also hear it. But that state of the world they are hearing is still sound1's; it's vibrations in air. They just don't know it. But they don't have to to talk about sound2's.

The problem with your objection is that sound1 is not identical to sound2.

There's no problem on my end. You're trying to allegedly "correct" me that Bob doesn't know what a sound1 is. But that's the same thing I'm saying... Bob doesn't know what a sound1 is. You're then saying that Bob only meaningfully talks about sound2's. But that's the same thing I'm saying... Bob meaningfully talks about sound2's. So the confusion I'm afraid is all on your end.

In other words, the vibrations in the air are not identical to the mental state of hearing.

Bob and Sheila cannot have a conversation (with spoken words, which it's reasonable to presume is the substrate of choice 20,000 years ago) unless they presume that they can make sounds that the other one hears. This presumption is equivalent to assuming that there's some sort of world state associated with the sounds they hear.

You're claiming they are, through the conflation I talked about.

I'm claiming exactly the opposite of this. I'm claiming that Bob and Sheila do not have to know about sound1 states to talk about them; because sound2 states are sound1 states. You're overly subjectifying sound2; you might be forgetting that Bob and Sheila communicate using sounds. By simply assuming they can communicate this way, they are assuming sounds are shared world states. Which, they are; they are, in fact, sound1's... vibrations in media.

That's not what sound is. ... You left off a crucial part. Sound is heard — RogueAI

It's hardly crucial, as this is a red herring. The sounds we're talking about are heard; Bob hears a sound and describes it to Sheila. Neither Bob nor Sheila are required to know that these things they hear are vibrations carried to their ears over a medium to talk about the sounds; all they need is to be able to sense and distinguish states of this sort. They can both do this because they can hear sounds.

But since you started a game of argument-by-dictionary:

In physics, sound is a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid. — sound (wikipedia)

If we're being accurate, two people from long ago aren't talking about sounds (vibrations in the air), they're talking about what they heard. — RogueAI

If we're being accurate, they experience "objective" states; they talk at all because they are socially minded, and being social, they notice that these things they hear are things other people around them can hear but only if the situation is just right (given theory of mind; also they don't need a word for objective here, which is why I quote it). The nature of this thing they both hear is what they are talking about. The nature of that thing is physical sound, but they don't have to know that this is the nature to meaningfully talk about it... they just have to know there are states that they can sense and distinguish.

Don't don any hat then. Pretend you're agnostic. Doesn't it sound absurd to claim that two people who don't even know what a brain is or that they even have one are talking about brain states? — RogueAI

Nope. People may have no idea that sound is vibration of a medium such as air (i.e., that sound is an "air state"), but still be able to talk about sounds. People may have no idea that mental states are brain states but still be able to talk about brain states in the same fashion.
ETA:
To meaningfully talk about states, all that's required is that you be able to know there are states, and be able to distinguish states somehow. You don't need knowledge of what the substrate or manifestation of the state is; just some sort of identity of the states would do.

But does a physicalist want to claim that anyone 20,000 years ago used "brain state vocabulary"? Isn't that prima fascia absurd? — RogueAI

I don't know, let's find out how absurd this is. Can Bob and Shiela communicate their mental states? Donning my physicalist hat, if you say yes, then it's not absurd to say 5 is false. If you say no, you're ipso facto saying 6 is false.

10. Therefore, (1) is false. — RogueAI

That 1 is false does not follow. E.g., 5 could be false, or 6 could be false.

"for any particular event, in its full context, there is some moral evaluation of that event in that context that it is correct for everyone to make — Pfhorrest
and in your example there is clearly some evaluation
You evaluate that both A and B are worse than C, D and E. That is a universal claim, it is enough to call it objective. — Congau

I think you're interpreting this a bit more broadly than intended. Consider that A, B, C are wrong, D, E are permissable, to Joe, if you're Joe. A, B, D are wrong, C, E are permissible, to Jack, if you're Jack. I would consider "A, B, C are wrong; D, E is permissable" a moral evaluation in the full context. I think you're reading this as "A, B are wrong" is "some moral evaluation" and therefore this is moral objectivism, but I don't think that's correct.

See Pfhorrest's clarification:

Most of what you're saying about partial orderings is morally objectivist in the sense I mean. It's only when you get to that C, D, and E might be "correctly" ranked differently by different people that you get relativist. If it is correct for everyone to assess C, D, and E as equally permissible, and A and B as equally impermissible, then that is a morally objective evaluation. It only becomes relativist if, for example, C is better than D according to one party, and D is better than C according to another party, and both of them are correct about those orderings "to each other" or something. — Pfhorrest

Compare to this from Noam Chomsky, per the link to moral universalism in the first post:

if we adopt the principle of universality: if an action is right (or wrong) for others, it is right (or wrong) for us. — Chomsky

In this particular abstract scenario, the intention is that there's room for a partial relativist interpretation; where everyone agrees A, B are less preferred, but there's more moral evaluation on top of that in this context that they would disagree on. To truly address a complete moral objectivist interpretation, everything that is wrong for a person should be wrong for everyone; and everything right for a person should be right for everyone (w qualifications; see that link). (Again, same qualification; I'm not arguing for partial moral relativism; I'm just saying your argument doesn't cover this possibility).

Yes, I doubt anyone is questioning that. — Noble Dust

Good... then we agree. This is just a tool to help with the reasoning.

I can't see how purely hypothetical moral options are useful in dealing with morality. — Noble Dust

Can you see how reasoning properly is useful in dealing with morality?

They are, exactly, abstract perfectly spherical cows; they are hypothetical fictitious moral options highlighting a gap in a specific line of reasoning... no more, no less.

I certainly hope there are more moral objectivists than relativists here, since moral relativism effectively means the belief there is no morality. — Congau

I don't think your reasoning works... it seems to presume that all moral options are either objectively well ordered, or have no ordering. As such, your reasoning is easily defeated by an objective partial ordering. For example, suppose it's simply the case that among 5 possible options A, B, C, D, and E; that A is worse than each of C, D, and E; and B is also worse than each of C, D, and E, and that these are the only objective orderings.

In this situation, we don't have an objective morality in the sense defined in the OP:

the claim that, for any particular event, in its full context, there is some moral evaluation of that event in that context that it is correct for everyone to make, i.e. that the correct moral evaluation doesn't change depending on who is making it. — Pfhorrest

...because whether C, D, or E is the best option may depend on particular value sets... so it's (at least relatively) relative. Yet, we also don't have an anything-goes situation, because either of C, D, or E would be preferable to either of A, B; and hence, there would still be such a thing as morality.

FYI, I'm not attempting to convince you of moral relativism here... I'm simply claiming that your reasoning seems to be based on a hidden assumption of a well ordering of moral judgments of options.

So I've no problems with 1. Regarding 2, "all" is a gigantic ask, and I'm not quite sure this is accurate. There are animal rights activists who favor the rights of non-human animals in their morality not from the perspective of human flourishing, but rather for the sake of the animals themselves. There are also in some moralities weightings of narrower groups, sometimes to exclusion of other human groups. We might also consider some moral precepts as favoring non-human groups (gods, the organization, etc).

Consider for example the animal rights activist. In particular, he might be morally against the avoidable torture of non-human animals. I would interpret your claim that his moral precept is an attempt to answer the question of what best serves human flourishing somewhere along the line of, if you were to convince said activist that such torture had no effect on human flourishing, he should be okay with it. But I'm a bit skeptical that once convinced of such a thing, your job is done; I equate that to his moral precept not being an attempt to address the question of human flourishing, but rather to be based on something else.

If all that is true, and I await a cogent refutation, we have an objective basis for morality and right conduct. — Thomas Quine

Not quite yet; it gets a lot muddier in the details. But we need not go there... one would have to agree that we're after human flourishing in particular to start down this road (i.e., agree with 2).
ETA:

If true, the thesis poses a moral challenge to religion, to policy-making, to the way business is done, to ideologies such as American exceptionalism and constitutional originalism, to law, justice, political regimes, etc. — Thomas Quine

I'm not quite sure this proposal is needed to analyze faults in some of these areas (see e.g. this thread).

Sure you can call it an explanation, but it is not really much of a one. — Janus

Sure, but it is one.

A proper explanation would not merely to identify what is going on,

Okay, so it's not a "proper explanation". Let's call it a clarification. But this clarification of morality proposes that moral precepts are attempts to answer the question about what best serves human flourishing. If all moral precepts, even hypothetical, even contradictory, could be argued in some convoluted sense to still be an attempt to answer the question about what best served human flourishing, then what value does this clarification actually have... what exactly is it clarifying?

It's not so much meant to explain anything as it is merely to clarify what's basically going on. — Janus

I don't see a difference. "X is what is basically going on" is the explanation. I'm suspecting the potential for illusory meaning... what exactly are you objecting to?

You might take issue with the OP's thesis that this basic logic of moral thinking is evolved — Janus

^^- FTR I made no mention of that.

And it would not be the basic logic of moral thinking if there were exceptions, so your attempted critique seems to fail here. — Janus

I'm more after meaning than science. Yes, this looks similar to falsifiability, but the basic idea is that if the thesis can explain everything, then it explains nothing.

all moral precepts are an attempt to answer the question, “What best serves human flourishing?” — Thomas Quine

This whole thread has a bit of a smell to me. Throughout this thread, this has been your general proposal. To some particular challenges to morality you have defended your general proposal by explaining how some particular moral precept which does not actually seem to serve human flourishing is, in fact, an attempt to answer the question of flourishing.

I would like to just start with the presumption that anything that anyone proposes, you would be able to fit to this thesis. So let's talk about that generically... what about the society of X-ists, who propose a moral principle of Y, which obviously is not about human flourishing? Well, here's the thing. Y might not really look like it's about human flourishing, but if you look at the X-ist society, their Y moral principle is an attempt to Z because they believe Z is the reason behind flourishing. This seems to be the generic recipe.

And that is where the smell comes in. So here's my challenge. If this is, in fact, a principle whereby you can always apply this recipe to defend your original thesis, then what is your general thesis actually saying? Another way to phrase this is, what sort of moral principles might we hypothetically find in some human society that would actually not follow from your thesis, but that we find in practice always (generally?) does follow? I would propose that if there is no such hypothetical violation, then the entire thesis can be dropped as being meaningless. The test of the thesis being useful is that there is such a hypothetical violation but we find in practice it's never (or maybe even rarely) violated.

The SEP is an excellent resource, and in section 2 we have a discussion showing that it is not straightforward to find an inverted spectrum scenario that is clearly behaviorally-invariant (and as we will see, my argument is not defeated by the existence of some scenarios that are.) — A Raybould

You're confusing your opinion with your argument. The stuff in section 2 is a different argument than what you've presented. Regarding that, some of the arguments in that section are in fact decent and relevant, but they do also presume things about color processing for which we really need more detail. For example, take this from SEP:

As noted in the previous subsection, there are more perceptually distinguishable shades between red and blue than there are between green and yellow, which would make red-green inversion behaviorally detectable. And there are yet further asymmetries. — Inverted qualia

...which does seem compelling (more generally, qualitative "inter-qualia" comparisons yield subjective asymmetries like this), but there are potential L1 reasons for this (via color opponency):

Red/green and blue/yellow are opponent color processes involving respectively some L-M and L+M-S function, with brightness being roughly an L+M+S function so close to just M that it's modeled that way in some color spaces. So for real colors, variance from green to yellow has L-M going from balanced to low without changing L+M-S balance much, whereas variance from red to blue has the same L-M variance going from high to balanced while also the L+M-S process goes from high to low. So in this case, the variation of real colors from yellow to green is expressed in the variation of just one color channel going from neutral to green, but the variation of real colors from red to blue is expressed in the variation of two color channels transitioning inversely from yellow+red to blue+neutral. Similarly with yellow versus brown being quite different versus blue and dark blue, yellow has an incredibly high brightness whereas blue starts out at fairly low brightness (relative luminance). Since these are L1 like properties, inverting the mappings from L1 to L2 colors may still carry these properties; IOW, an inverted spectrum might not quite be as much like flipping an RGB image's colors as one might presume.

"Too vague" seems to have become your default response, but by itself, it is too... vague? — A Raybould

It's not exactly a default response so much as it is prompted:

A more parsimonious expectation, however, is that this multi-generational training has produced brains that function alike, to a first approximation. If they did not, how likely is it that they would have, so to speak, 'learned the lessons' imparted by evolution? — A Raybould

...in relation to the topic at hand, this is indeed too vague. Your expectation is more parsimonious than what exactly? Function alike in what ways? What "learned lessons"? I'm perfectly happy to say that human brains evolved in human like ways, but that does not really imply same-experience unless you can connect the similarity of human evolution to the similarity of color experience, which I've yet to see. Other than that, it's yet another nature versus nurture debate. Truth is, both nature and nurture make brains, especially human brains.

My point is based on empirical fact: if variation is routinely producing children that have markedly different functional responses to color stimuli than their parents, then how come we only very rarely see those variations that do not result in observable differences? — A Raybould

Because, for example, predators aren't examining your brain with fMRI to see if you represent redness on this spot or that spot or using this average frequency of pulses or that frequency? The important thing from a fitness perspective is that you run away, hide, or fight the predator appropriately.

The alternative is so lacking in plausibility that I will not bother to reply until specific arguments for it are presented. — A Raybould

That's your choice, but in effect, given that you're the one claiming to be supporting a proposal that the experiential correlates have a fitness advantage, not answering the question absolutely equates to not addressing the very thing your proposal is supposed to be about. If your proposal is about a tie between fitness and particular experiential correlates of color, it is backed if and only if you can demonstrate what it is about... i.e., tie fitness to experiential correlates of color. This is what I mean by relevance.

For physicalists, where there is no physical difference, there is no difference simpliciter. — A Raybould

Sure. So let's focus on the correlates, since that's where the difference would be.

And what are those correlates? — A Raybould

I don't know, but I think that's the key question. In terms of L1 colors, there are reasonable explanations of development that are works in progress but involve self organization; these generally produce opponent color processes. Example:
https://www.frontiersin.org/articles/10.3389/fncir.2014.00016/full
This itself requires a bit more study. In terms of color perception in the brain, as I said before, we know there are multiple places of analysis. But there's also the possibility of potential signal space (such as these toy models of potential Poisson rates)... and since the signals potentially start this way there may be transference from these signal rates to positions, or not. But "qualia" may be more complex than many philosophers tend to treat it as well; e.g., there's such a thing as pain that doesn't hurt, suggesting that qualia aren't necessarily singular in the first place. This might be explained as pain in practice actually having separable pieces that typically are co-associated but not essentially so, and the same could possibly be true of color. What we're looking at developmentally for different-experience would be any sort of theory that starts with this brain in a semi-random developmental state and just "settles into" the "nearest corners". The entire question here (that has not yet actually been addressed) is how many "corners" are there, why are there that many, and how do the L1 colors map into them? Assuming opponency-sized "corners", a same-experience theory would postulate four to six of them, and some sort of specific developmental pathway whereby particular opponent signals latch into the specific four (or six) that they're supposed to map to.

What I am saying here could be falsified — A Raybould

...I'm fine with that, but "adequately justified" is more akin to what you're saying being verified.

Argument and counter-argument are the principal methods of philosophy — A Raybould

Yes, but counterarguments should not have to require an opposition taking a side to provide the counterarguments, and most certainly should not require the opposition to hold the countering view as an opinion. Also, two people discussing a thing need not necessarily each pick a corner and box; it's entirely possible, and may even be more productive, for the two to simply walk hand in hand from corner to corner.

Furthermore, any scenario, in which the different-experience hypothesis has a difficulty explaining observations and the same-experience hypothesis does not, is an argument (or evidence, if it is an empirical fact) for the latter over the former. — A Raybould

So, let's get back to tetrachromacy. Let's suppose we introduce a new gene in the human gene pool, call it OPN1MW3. OPN1MW3 expresses in people who have it by producing an M cone with spectral sensitivity shifted towards blue by the same amount (measured in frequency) that M shifts L spectral sensitivity towards blue; let's call this a N cone. This gene is an allele for the M on the X chromosome. So suppose we have: (a) Adam, who has L, M, and S cones; (b) Bill, who has L, N, and S cones; (c) Cindy, who has L, M, N, and S cones. So here are some questions. (a1) Is Adam likely to be a trichromat? (b1) Is Bill? (c1) Is Cindy more likely to be a tetrachromat or a trichromat?

(c1) is the interesting question... but regardless of its answer we still have followups. If the developmental process is such that Cindy's likely to become a tetrachromat, then there are questions about what exactly causes the L2 colors that Bill sees; your hypothesis suggests it's some built-in gene, but if self organization suffices to establish L2 colors this is questionable. But if Cindy is only a tetrachromat if she has some other specific gene, some BN (brain-gene-N analog; here, this is just a generic referent... it could be more than one gene), that pre-structures her brain, then we must also ask whether Bill can have that gene as well, or under what conditions precisely Bill sees what Cindy sees that Adam doesn't see.

Your hypothesis seems to require a "BM" gene of sorts. Okay, we have the human genome mapped out... so which gene is BM?

While your stated position, being indefeasible (though trivially so) is a strong one to sustain during a debate, its usefulness in the search for knowledge is wholly dependent on other people looking for answers. — A Raybould

The point isn't to simply maintain some position with unreasonable standards though. The point is to require relevance. The thing being talked about here is the actual stuff happening between our ears in our soft pink squishy warm brains, that has to do with our subjective conscious experience of colors. Some discussion of and/or constraints on how that subjective experience's correlates develop is necessary to provide a theory of how much the subjective experience's correlates can vary. Without having that discussion or addressing what those constraints are, you're just plain not having the required conversation.

While your stated goal, apparently, is to show that the notion that our experiences are similar to a first approximation does not achieve hypothesis-hood — A Raybould

I've no objection to same-experience as a hypothesis. My objection is claiming that the hypothesis is adequately justified prematurely.

I am guessing that your emphasis on 'established' indicates that you were aware of this, but I had in mind cerebral and congenital achromatopsia and dyschromatopsia, color agnosia — A Raybould

Achromatopsia and dyschromatopsia are the same modes of L1 level color deficiencies previously discussed (though there are acquired forms). Color agnosia as far as I'm aware is a defect of the ventral stream, which is particularly interesting for awareness of L2 colors at all (if not L2 modes of color at all). I would be interested in an L2 specific defect.

The only invocations of inverted qualia that I am aware of are in modal metaphysical arguments against functionalism. — A Raybould

See section 3: https://plato.stanford.edu/entries/qualia-inverted/

I may be mistaken, but I do not think that even a majority of the philosophers who invoke these arguments have much commitment to the proposition that such cases occur in the actual world, and the philosophers who do seem to be a minority of all philosophers.

I'm not so concerned with consensus among philosophers or any group of people for that matter... a million guesses is still not evidence.

More generally - and I think it covers all the points you have raised here - you are saying that there are cases where disparate experiences would have no observable behavioral effects, and I am saying that nevertheless, there are other cases in which they would — A Raybould

I agree on that part, but I think you're confused. You specifically asked me for arguments to support that our color experiences were fundamentally different... I provided them.

It is my impression that the idea, that we cannot and could not tell if our experiences are the same, is the majority view, and it is one I used to hold, but I have come to think of it more likely than not that they are, up to the level of first-order effects. — A Raybould

Great! This is certain to be a more useful analysis. But going in, I disagree that the premise "we cannot and could not tell if our experiences are the same" is justified.

Empirically, neurophysical studies using multiple subjects work - they produce quite specific results that ... — A Raybould

...okay, so I'll call this the architectural argument.

It would be a fair point to say that these studies have only gone so far in figuring out how brains work, — A Raybould

It's true that we share general architectures; this is the foundation for being able to describe such things as the visual cortex, areas V1 and V4, the ventral and the dorsal stream, and such. But it's still a bit of a mystery how colors are encoded; so far, color analysis seems to be a bit distributed. So yes, we can't quite claim that we've figured out how the brain works. But, yes, this is the most promising area of study, and this is the type of thing to appeal to in such arguments, but there's a bit more work to do. You still can't quite say though the architectures are the same therefore the experiences should be. You have to call apples apples and oranges oranges. You should talk about the candidates for the experiential correlates being the same. Just because our brain shares an architecture doesn't mean it'll share everything.

A dualist might say that it is possible for two people to be identical in every possible physical way, and still have different experiences — A Raybould

Sure, but I'm not sure dualists can claim adequate justification.

You have attempted to dismiss this as my attempt to impute attitudes to researchers — A Raybould

Not exactly... I've pointed out a situation where you're basically guessing researchers share your view and then appealing to the researchers having your view, which is basically an appeal to authority as a fallacy.

Secondly, the human brain is a network of neurons trained over hundreds of millions of years, and at each generation, the information accumulated by that training is squeezed into DNA and reconstituted. It is certainly possible that, while externally our minds function similarly in many ways, under the hood, each brain is working quite differently than any other. A more parsimonious expectation, however, is that this multi-generational training has produced brains that function alike, to a first approximation. — A Raybould

The description here in terms of evolution sounds a bit Lamarckian. Also, this is quite hand wavy. There's "information" that we share based on evolution. From there, you go to specifying that particular kinds of "information" must be shared, because the alternate theory is that "information" is not shared.

If they did not, how likely is it that they would have, so to speak, 'learned the lessons' imparted by evolution? — A Raybould

Too vague and hand wavy still. Evolution isn't a teacher teaching individuals lessons. It's just a blind process that happens to do what it does. Natural selection tends to keep the genes around that tend to stay around; sexual reproduction tends to shuffle genes around; genetic mutations of specific types tend to just happen at particular rates. Brains don't just behave... they learn; ANN's aren't quite the same thing as a brain, but they're success stories (to the degree that they are) in mimicking how brains learn at some level. Behaviors important to survival are significant, but brains come with hormone systems, body sensations, drives, and instincts for such things. Also, it sounds pretty expensive to code entire brains into a genome, in terms of genomic cost, and evolution is known for being "good enough" (it's why we tend to die of old age... we simply don't need to live that long to pass our genes into the gene pool so the selection pressure dips below what's needed to keep up with mutation rates).

If a child's high-level brain function can vary markedly from that of its parents, how likely is it that it would nevertheless still be behaviourally similar enough that the child has approximately the same level of that part of its fitness that comes from its mental abilities?

We're not talking about high level brain functions here. We're talking about the experiential correlate of a color.

Alternatively, what sort of mechanism would be needed to conserve the external behaviour in the face of internal variation? — A Raybould

Any isomorphic mechanism would do the trick. Instead of using high and low circuits for 1's and 0's, we could use magnets being in the same or different directions. It doesn't really matter, so long as a change is a change. Instead of encoding y as glucose in the solution we could encode it as maltodextrin.

We cannot depend on evolution doing that, as evolution is itself dependent on the conservation of fitness traits from parent to offspring. — A Raybould

Evolution is only selecting for fitness where it matters. If a variation does not affect fitness where it matters, evolution would not care about that variation. You're in effect just begging the question; you're assuming that the variations would have an effect on fitness and then arguing that evolution would select those out:

we can have various colors of our irises because the particular hue of their pigment does not strongly determine fitness and so is not strongly selected for. — A Raybould

So green versus blue eyes don't seem to matter much to fitness.

I do not think it is very speculative to say that our mental abilities are strong determinants of fitness (unless, of course, one thinks our experiences are epiphenomenal.) — A Raybould

In what way?

So this is all speculative, but I wrote this earlier, and you said at the time that you accepted it: — A Raybould

...not quite, but the disagreements are in the weeds (e.g. it's possible to formulate a theory before a hypothesis)... and not quite useful for this discussion.

Furthermore, what are the counter-arguments, other than that it is speculative, which isn't a fatal flaw in a mere hypothesis? — A Raybould

Counter-arguments fall back to debate mentality. What we're really interested in is the truth. So the analysis to be done on a hypothesis is to explore the ways in which the hypothesis could reasonably fail. That's what I've been doing here.

but how are these flaws manifest in this particular argument? — A Raybould

It's very simple. The burden aligns with the purpose. Let me start with a summary of what I see you as doing and get back to this.

You are advancing an argument that evolution theory suggests same-experience... the burden on that is fairly high, and has not been met. To adequately justify this, you need to show how evolution is inconsistent with different-experience. The first argument you advanced failed very quickly with a sanity check; green-eyed people not being universal suggests that evolution doesn't always produce universal traits. What was really missing from this argument was relevancy. You did a little better with the second argument but you're still missing the relevancy... you seem to beg the question by thinking backwards about it, something along the lines of "if different-experiences were had, there would be differences in fitness". I claim this is backwards because you're trying to start at evolutionary fitness and then conclude same-experience, so the real challenge here isn't fitness-affecting differences, it is fitness-invariant differences.

That's where the arguments I'm providing come into play. The purpose of these arguments is different, and along with this comes a difference in burden. There is no argument on the table that evolution supports the different-experience theory, so there's no need to demonstrate that it does. The argument rather is that evolution is compatible with different-experience theory. If it's simply compatible, then we can reach the intended conclusion, which is not that we have different experiences... but, rather, that you have yet to adequately justify that we have same-experiences. Now were the argument on the table that we actually have different-experiences of color, the burden would shoot up matching the burden I'm expecting of you. But the actual stated position I'm taking is a non-position.

that people to generally agree on categories implies a degree of commonality in the mapping of sensory input to experience — A Raybould

There's a difference between a mapping being equivalent and the thing being mapped to being the same. This is how you originally engaged me:

It doesn't approach being a proof, but, IMHO, it is a plausible hypothesis. Per my earlier post, I would not propose that everyone's experience is the same in detail, but that for most people, there is a broad degree of functional equivalence. — A Raybould

What arguments are there for the proposition that everyone experiences things fundamentally differently? — A Raybould

I read "in detail" and "fundamentally differently" as describing that what's being mapped to being more or less the same. Additionally, you posted the first thing in response to this quote:

but to simply conclude that the color experiences are the same because we're all human sounds to me more like guesswork. — InPitzotl

So I'm not quite sure "straw man" is the right term for it... it's pretty easy from this reading to get the interpretation that you're claiming that if the mapping is the same then the things being mapped to should be the same. But let's just clear that up right now.

Are you arguing that if the functional mappings are equivalent (say, in the sense that if the behaviors of ranking things into categories are the same), that this implies that the experiences are the same?
ETA:

We also have examples of second-order variance from this commonality, as demonstrated by various forms of color-blindness, which need not necessarily arise at L1. — A Raybould

I have no idea what you mean by "not necessarily" (are you envisioning some universe where established science is wrong?), but it's already established that protanopia/protanomalies are associated with L cones, deuteranopia/deuteranomalies are associated with M cones, and tritanopia/tritanomalies are associated with S cones. We know that the former two are common in men due to the fact that the genes for L and M cones are on the X chromosome and absent on the Y chromosome, so females get an extra copy of them (note that S cone encoding is not on this chromosome). For similar reasons it's females who tend to be tetrachromats because the rarer OPN1MW2 gene could be present on one of these X chromosomes, and OPN1MW1 on the other, presenting as two different encodings of "the M" chromosome. These genotypes encode for differences on the opsins, and differences of the opsin proteins modulate the sensitivities to particular frequencies of light that these proteins react to when they photoisomerize (fold based on absorbing a protein), which is the primary biophysical mechanics triggering color vision. (Note: There are also L cone alleles). The effect is that these two variants of M chromosomes in effect become two distinct photoreceptors. So according to these established modes of color blindness (and tetrachromacy), they are in fact at the L1 level.

Also, obviously, we don't actually agree that our L2 colors are similar... otherwise, philosophers wouldn't brandish about terms like "inverted spectrum". — InPitzotl
Please explain how the conclusion follows from the premise. — A Raybould

It's almost a direct translation. L2 colors are our experiences. An inverted spectrum philosophically is by definition an inversion of the experience of colors, ergo, it would be an inversion of the L1 color space mapping to the L2 colors.

It's because you keep talking about behavioral responses and disagreements on whether all people would agree that particular things are red if they simply have different L2 colors but share L1 colors. — InPitzotl
While you are about it, please explain how that follows, also. — A Raybould

If there's an inverted spectrum, the mappings from L1 to L2 colors would be inverted, but the continuity of said mappings need not be affected. The only behavioral argument on the table so far is: "evolution is very conservative about things that are important to fitness, and our minds". That reasoning presumes there's a fitness advantage, but you would need to explain an actual advantage to make this argument solid (again, we don't all have green eyes by this argument).

That's my point about your argument - you are making assumptions - assumptions that are more consistent with experiences being similar than different — A Raybould

Try to pretend for a second that you understand math. Abstract the nature of experience out and let's talk about pure vector spaces. One example vector space would have a certain amount of salt mixed with a fluid; a certain amount of glucose, and a certain amount of alcohol (note that we're not concerned with infinite vector spaces, since color space is restricted to a range, so this works perfectly well). We could encode something like CIELAB (x,y,z) as distinct concentrations of salt, glucose, and alcohol mixed in the fluid. We could also swap out glucose with maltodextrin. (NOTE: There's no proposal here that experiences are solutions... I'm just showing you just how wild and arbitrary you can get when creating a vector space; outside of this parenthetical, precisely because it's arbitrarily wild, I'll come back to solution-theory of experience as a proxy). As another example, we might encode color as an oscillating function of some value varying in time, like a sound wave... x's basis could be assigned to 10kHz oscillation, y to 8kHz, and z to 7kHz, such that we have a color encoding of f(t/2pi) = sin(10000t)x + sin(8000t)y + sin(7000t)z. We might consider swapping x's basis from a 10kHz frequency to a 12kHz one (along these lines, we can also choose phase encodings or any of a number of things). I could invent vector spaces here all day long.

You've invented some sort of abstract vector space where linear correlations are no longer linear correlations, such that something would be "more consistent with [vector bases] being similar than different", but that is incoherent gibberish to me. The linearity of our mapping to saline-glucose-alcohol solution has absolutely nothing to do with the fact that we used glucose here as opposed to maltodextrin as the basis vector. The linearity of our sound encoding has absolutely nothing to do with the fact that we assigned x's encoding to 10kHz as opposed to 12kHz.

So what pray tell are you even talking about?

Equally for your assumptions. You are being inconsistent. — A Raybould

I'm more than willing to grant that variability on experience (among people) needs study; the point of going over these examples and objections isn't to present an opinion, but rather to present reasons not to form a particular opposing one until we get more information.

But I don't think your objections about the linearity of a vector space depending on what the basis vector represents are even coherent. It appears to me that you're trying to support a conclusion that if everyone agrees this is orange, their solutions representing the color must all use glucose, because we would have to make an assumption that maltodextrin solutions can also represent consensus of orange before concluding that it could possibly be maltodextrin. That is the very kind of thing I'm arguing against... garbage arguments for an opinion (in this case same-experience), which push comes to shove are double standards of burden of proof (too low justification required to conclude same-experience but more than what should reasonable required to reject it). You should not in this case claim that you have adequately justified same-experience until you have measured the glucose in the solutions of various people.

I cannot imagine why you think I am confusing L1 and L2, but there is nothing to be gained by following that any further. — A Raybould

It's because you keep talking about behavioral responses and disagreements on whether all people would agree that particular things are red if they simply have different L2 colors but share L1 colors.

Possible? Certainly. Likely? I was already of that opinion, based broadly on the sort of evidence and argument you are presenting here. — A Raybould

But hang on... that, too, is the wrong takeaway. There are arguments for same-experience that you have not yet given. There are also counterarguments to those arguments. But in the end you still wind up at my position... that we simply need more study.

Necessary? No; if we are going to suppose that everyones' experiences of color are different, without any constraint on how different they might be, then we cannot assume continuous variation, let alone any isomorphism between individuals, or even any stability within a single individual. — A Raybould

The how-different is irrelevant. There are two vector spaces, and you can map them up linearly or non-linearly (pre-adjustment of the sort we see in the cube). Our L2 colors appear to align more or less linearly. There's an implied hypothesis that the mapping would be linear. I get the impression that you somehow think that the very linearity of the L1 to L2 mappings critically depends on what the basis vectors in the L2 space represent.

The point here is that the assumption, that we would both agree about the redness of all (or most) things, is predicated on assumptions about our experiences being similar. — A Raybould

Wrong. For us to agree about the redness of all (or most) things, the only thing that is necessary is that we form the same categories of L2 colors that vary in the same way to L1 color spaces; it is entirely unnecessary that the L2 colors themselves be the same. The presumption that our experiences are similar is not yet warranted. Given Jane is a tetrachromat, we could have j-red, j-green, j-blue, and j-c4. Your "red" could be j-c4; my "blue" could be j-c4 (incidentally, these are just simplified illustrative mappings). Also, obviously, we don't actually agree that our L2 colors are similar (your phrasing, "our experiences being similar")... otherwise, philosophers wouldn't brandish about terms like "inverted spectrum".

Okay, so since we keep going back and forth over this point, I've cobbled together the following illustration. Here's a color optical illusion based on Beau Lotto's famous cube illusion:

Here, the two color swatches on the large cube indicated by the corresponding color swatches on the gray cube are the same color.

This diagram illustrates three different layers of "color"... layer L0 indicates the physical spectrum. Layer L1 is what the cones in your eyes resolve (what I'm calling here colorimetric). Color experiences occur in this diagram at layer L2. The reason for using this illusion is to highlight that L2 colors are distinct from L1 colors, because certainly since these two indicated swatches are the same color spectrum (L0), the cones in your eyes would respond the same way (L1), so any difference you see (experiential) is upstream (in our discussion so far I keep getting the impression that you're confusing L1 with L2).

L2 colors, mind you, cannot distinguish something if L1 cannot distinguish it (under the presumption that our eyes are actually serving some sort of purpose... that we're not just psychically sensing color independent of our cones). We should for example expect the same color illusion works the same way if we replace the L0 color here with a metamer (another spectral color that our cones cannot distinguish). Likewise, it appears to be common that whatever color experiences we actually have, behaviorally we tend to sense that the L1-colors (in say CIELAB space) seem to vary naturally according to variances in our experiential L2 colors.

Now get back to the hypothetical tetrachromat. A tetrachromat's L1 color space should be expected to be 4 dimensional just as us trichromat's L1 color spaces are three dimensional. Under the presumption that tetrachromacy works similar to trichromacy, we would expect some 4 dimensional CIELAB-like L1 color space; some trichromat metamers would be distinct L1 colors for such tetrachromats. In this 4D-CIELAB space we might presume L2-colors to vary roughly according to the L1 colors, but there would also be more L2-colors. Presume then as a rough model that we take a 3D slice of this 4D L2-color space that roughly corresponds to one trichromat's L2-space. Would we not be able to take a different 3D slice of this 4D L2-color space and have a second trichromat have this as his L2 colors, and still have the property in both individuals of having each of their L2 colors vary continuously in correlation to the 3D L1 color spaces?

Feel free to reply at the greatest confidence level you think can be justified. — A Raybould

"Justified" isn't the point. Purpose of holding this burden is. Usually when I see the certainty burden it's an indicator of a double standard of burden of proof; one holds some opinion A and then one adopts a "prove me wrong" view, with the naive idea that they're open minded because they will consider other opinions, but the pragmatic idea that they hold opposing opinions to A to a much higher standard than opinion A itself. What I'm questioning isn't what burden can be met, but why you are applying this burden.

FYI, I already listed (response to very next quoted snippet) reason to suspect agreement; I'll back fill this with more detail for you some time later when I get time if you like.

I think it is sometimes called 'yellow' (if I am recalling that usage correctly) because it is a variant of the more common green opsin, with a spectral response shifted towards longer wavelengths. — A Raybould

That actually describes erythrolabe (the L opsin). (I'm not saying anything's wrong here BTW, just that it's a bit interesting to hear talk of yellow-sensing cones)

If two people differ in their experience of a class of stimuli, is there any reason to be certain that they will be able to come to an agreement on how to categorize them? — A Raybould

Is certainty an appropriate burden for some purpose here?

We don't learn what 'red' means by memorizing a canonical chart of all the hues that are red. — A Raybould

The color categories are in large part shaped by cone properties. Metamerism for example is an expression of different spectra that have the same effects on the cones.

And there are behavioral differences: for one thing, tetrachromats behave differently than most of us in the tests that demonstrate their particular talent. — A Raybould

Now I think you're lost. We're talking about two trichromats with similar cones potentially or not as the case may be having different kinds of color experiences. Tetrachromacy comes into play here only by comparative speculation that there might be different modes of experiential color than the ones trichromats have, which suggests different potential experiences.

BtW, I recall seeing some fairly convincing evidence (some variant of the Ishihara test), a few months ago, that a small percentage of women are functional tetrachromats, having two different yellow-detecting pigments, but I do not recall where I saw it. — A Raybould

https://en.wikipedia.org/wiki/Tetrachromacy#Humans
I have to say though... it's a bit interesting seeing this called a yellow-detecting pigment.

Not necessarily - it seems quite possible that, while we might agree that certain things are red, we might not agree on others. — A Raybould

I'm a bit lost. You're now speculating that there are behavioral differences?

so which one of me tips the waiter? — Kaarlo Tuomi

Schrodinger only proposed this mind experiment to show how absurd the Copenhagen interpretation is — Olivier5

Here: https://www.youtube.com/watch?v=kTXTPe3wahc
(20 minutes, but worth the watch, and you can play faster if you like)

The cat in the box is an observer too. — Olivier5

Schrodinger still sees a wavefunction. If you posit that the cat is an observer, then there are two cats; a living one, and a dead one. But Schrodinger still only sees one wavefunction (before opening the box). This is part of the core of MWI; the wavefunction that Schrodinger sees is basically a combination of two "worlds", and when Schrodinger observes this, he just entangles with this wavefunction, after which, there's a Schrodinger that sees the dead cat, and a Schrodinger that sees the live cat; both Schrodingers are part of the universal wavefunction.

I was asking you and Kenosha if the observer effect has more to do with how observations/consciousness behaves rather than how quantum particles behave when being observed. — Harry Hindu

In a double slit experiment, there's "a setup" where you see an interference pattern and "another setup" where you do not. So (a) conscious observers can tell the difference between seeing an interference pattern and not seeing interference patterns. Suppose then that consciousness had something to do with QM; one would then think one could (b) create a setup such that if an observer (subject) was conscious, the (conscious) experimenter would see no interference pattern, but if the observer (subject) had no consciousness, the (conscious) experimenter would see one.

(b) is actually quite a powerful result; it is tantamount to a test for consciousness. We don't actually have (b) though; if we did, it would be a lot more powerful than simply making a strange theory few people understood... we'd be putting everything from tardigrades to puppies in the thing testing which entities had consciousness.

I think the cat would disagree with that. — Olivier5

Which cat? The living one? The dead one? Or the cat wavefunction that Schrodinger sees?

How long, I wonder, would you have left me under the impression that you still held that view? — A Raybould

For one thing, you say "I'm not too interested in fleshing out this theory since I don't particularly subscribe to it", which is rather an odd thing to say about something you had postulated only a few hours before as if it were a strong argument for your position — A Raybould

Ah, I see why you were confused now. But I think maybe you want to read this post a bit more carefully before suggesting that I might have misled you.

so it seems that you changed your mind during the time when I was probing its relevance. — A Raybould

Nope, I did not change my mind. I still say that "evolution is very conservative about things that are important to fitness, and our minds" is a bad argument for same-experience theory.

there is no hand-wringing over whether the subjects will be similar enough in their responses to justify the approach, and I would bet that the possibility that it would not be is rarely an issue in the funding of such experiments. — A Raybould

This sounds a bit fishy to me. It sounds like you're guessing that the researchers secretly agree with you, "betting" that they do, and then appealing to this secret agreement.

As for your examples of synesthesia and tetrachromacy, it is not unreasonable to consider them as second-order effects. I don't think many papers reporting this sort of work contain the caveat that their results cannot be extended to these cases. — A Raybould

But hang on, that's the wrong take-away. Let's focus on tetrachromacy a bit more... if a human develops tetrachromacy, would you think it reasonable that said human would have more color experiences? I mean either it's that, or somehow the same color gamut just gets "redistributed", or we just happened as human trichromats to max out on the number of potential color experiences (or, supply your own other?) If tetrachromacy does lend to more color experiences though, then there are indeed more potential color experiences to be had. So the next question to ask is, do we need to add more stuff to the brain in order for it to be able to have these additional color experiences, or would the brain somehow wind up with them if we had four cone types giving us richer information? We could ask the same question on lower levels (e.g., how the ganglia forming color opponent channels in the retina would organize), and that leads to questions about, gee, how do they organize anyway, in us trichromats?

Do you see what I'm getting at? None of this actually argues for different-experience, but you certainly can't just handwave same-experience without understanding how this stuff works in the first place. All of these are good questions, and they really require more study.

Given the results of this experiment, perhaps you consider color categorization to be a counterexample to the hypothesis that most people's responses to stimuli are broadly similar? — A Raybould

I think that question is making assumptions that are not yet justified. A response to a stimulus is behavioral. What effect would having different kinds of experiences of similar stimuli have on the behavior? If I experience red a different way than you experience red, wouldn't we still both call red things red?

my understanding is that when the cat is in the box, the probability that it is alive equals the probability that it is dead, so the cat is considered to be both dead and alive at the same time. — Kaarlo Tuomi

Probabilities come into play when you apply the Born Rule, and that's the rule you apply when observations are made. While the cat is in the box, it is in a superposition between dead and alive. The state is described as a wavefunction.

we assume the probability that I will pick any given flavour is equal, so that before I pick a flavour, I am assumed to have picked all ten flavours at once. — Kaarlo Tuomi

Having ten flavors does not equate to the probability of each flavor being chosen being 10%.

there is also the multiverse theory, which says that for every choice I make, there is an alternative universe in which I made some other choice. — Kaarlo Tuomi

There's a bit of speculation being applied here that our choices are represented via a wavefunction. QM applies to the mechanics of physical entities. Agents make choices "somehow". But just because agentive choices appear in some fashion to be similar to states in superposition does not mean that an agentive choice is a quantum superposition of possibilities. Perhaps it is, but perhaps it isn't... it would not be inconsistent with quantum mechanics to speculate that your wavefunction could only "reasonably" evolve into your selection of flavor 3, despite the fact that you're mulling over 10 flavors. I think certain philosophers try a bit too hard to link will to QM because they think they need QM like properties for some theory of free will, but I think the latter is mistaken (and QM doesn't quite help explain free will thingies in the way it's usually "needed"), so I would advise proceeding with caution.

It is not clear to me what you have in mind here, though it seems to be suggesting a chaotic process — A Raybould

Why would you need to appeal to chaotic processes?

but whether that is so may depend on what you have in mind when you say "a large number of potential experiences" — A Raybould

Start simple. Imagine we develop a fourth cone type and manage to develop tetrachromacy.

At least until you explain these matters, it is not clear to me that you have a viable argument for your position. — A Raybould

You're making the wrong appeal to the wrong person. I'm not playing the debate game; in fact, I'm skeptical of that entire game. Convincing you isn't the prize I'm after. Tossing that away, the only reading of that statement left is that you're declaring dependence upon me to question your premises for you, which I read as a bad thing.