If it’s worth saying, but not worth its own post, you can put it here.
Also, if you are new to LessWrong and want to introduce yourself, this is the place to do it. Personal stories, anecdotes, or just general comments on how you found us and what you hope to get from the site and community are welcome. If you want to explore the community more, I recommend reading the Library, checking recent Curated posts, and seeing if there are any meetups in your area.
The Open Thread sequence is here.
Hi all. My name is Dave, I recently went along to some AI Risk for Computer Scientist workshops and consequently read Rationality: AI to Zombies, HPMOR and The Codex, and have been generally playing with CFAR tools and slowly thinking more and more AI safety related thoughts.
A few coworkers have also been along to those workshops, and some other people in my various circles have been pretty interested in the whole environment, and so I'm currently polling a few people for interest in setting up a LessWrong meetup in Brisbane, Australia. I'm looking forward to seeing what comes of that.
I've also ramped up my lurking on LessWrong itself, and so hopefully you'll see me in the comments section whenever I next feel like I have something interesting to add :)
Yeah, agree with that. We have some plans for making this happen, though we hadn't considered doing the same for comments. I will think more about that.
The basic idea was basically to improve the sequence UI and make it much easier for people to create their own private sequences and add posts to it from the triple-dot menu on posts. We could likely do the same for comments, though capturing context there is a bit harder.
Sequences are all well and good, but that’s much, much too high-overhead for what I’m talking about. Just put a little star icon on every post/comment; when you click it, it lights up; and then on your user page (or something) you can view a list of all your “starred” comments and posts. That’s it!
(Also do the sequences thing, why not. Do any number of other things, sure, but definitely do this very simple and easy and intuitive and broadly useful thing!)
Edit: Then maybe the sequence creation UI could make use of this, like maybe there’s a little “your starred posts” list there and you can easily pick from those, to add to your sequence. And maybe the “insert link into post/comment” button in the editor UI could offer you a list of your starred posts/comments (most recent? all?), to insert those links. Sky’s the limit for utility, here…
Yeah, the team has discussed bookmarks a bunch and I expect us to implement it sooner or later. And oddly enough, when we thought through the features we'd want out of bookmarks, they did end up looking very sequence-like, to the point that we considered retrofitting "sequence" into a more general version of itself.
(i.e. you could easily want multiple reading lists, arranged by topic or how-much-effort it seemed to read)
[meta] is variable and strong voting having the desired effect? I use it pretty rarely, and often go back and reduce it to a regular upvote if there are a number of other voters that I don't want to outweigh. I've noticed on my own comments, though, that sometimes a single voter will move a score by 5-10 points, which is nuts for a comment that only has 4 votes and a total of 12 to start with.
Can I opt to just see number of up- and down-votes rather than the hard-to-parse weighted totals, at least for my own posts and comments (the ones I want a signal for)?
You are doing some fancy footwork with the labels there. As soon as a post rationality method is describable, repeatable and documentable it woild fit into rationality. But what about the concepts that don't fit into words so easily. The map-territory bridge problem (describe how to make a bridge between the map and the territory).
Alternative medicine has some interesting features worth investigating (deliberately left vague).
As soon as a post rationality method is describable, repeatable and documentable it woild fit into rationality.
It already fits. For example, in "The Rhythm of Disagreement", Eliezer talks about the "rhythm" of Bayesian reasoning, the fundamentals that come before any formalised method, that you have to adhere to even if you don't have any numbers to apply Bayes' Theorem to. He illustrates this with various examples, rather than laying down a "describable, repeatable and documentable" method. This bears out Raemon's comment that everything advertised as postrationality is already in Eliezer!rationality. And Eliezer!rationality is the rationality we are concerned with here at LessWrong.
Gosh I hope not. I hope we developed the craft further than the guy who mostly stopped publishing on the site by 2011.
I would appreciate "Lesswrong" not standing in a shadow and instead building on existing work.
I propose that PR is a natural progression from R. (hence the name PR). I expect to see places where R occasionally stretched into places that made space for PR to grow out of.
I would appreciate "Lesswrong" not standing in a shadow and instead building on existing work.
So would I, but I don't think I've seen much that qualifies. There is the work on AGI, but I don't know how far that has gone, because I don't follow it (a topic of vital importance that I have chosen to ignore, there being only so many hours in the day). Perhaps CFAR? But they don't publish, and I have not been to any of their events.
It already fits
Except that for some techniques I had to step out of rational into "weird" to develop it. For example focusing is a technique in rationality that talks about interior subjective experience of a feeling of a knot of a problem and what could often be referred to the same phenomena as "energy channels". A very alt-medicine-esque concept. I put focussing more in pr territory than in R territory. Particularly in the mind that developing further techniques needs to be done from a different experiential space.
That is - as Thomas Kuhn suggests in proposing paradigm shifts in the book "the structure of scientific revolutions", to get novel science we need to do novel experiments with novel apparatuses. To revolutionise what we know, we need to explore something we haven't already explored.
I think if rationality need to regularly explore concepts that don't fit into words in order to be successful, then rationality should just not stress out when it can't put concepts into words.
(It seems that both epistemic and instrumental rationality need this, for different reasons).
My biggest pet peeve with post-rationality (esp. as described as relating to LessWrong) is that it doesn't seem to be doing anything that Eliezer doesn't at least point to once in the sequences and say "this seems like it's going to be important", even if Eliezer isn't an expert on it so didn't have much to say.
I get a lot of flak from rationalists when I try to do stuff in the weird word territory.
It's clear to me that the delineation is both necessary and helpful for people who are still getting the hang of interpreting weird words and for people well versed to find each other and compare notes.
To mush all PR into R isn't making anyone happy.
I see R folk complaining about PR. I see reductionist R folk, trying to deny the existence of PR. I see PR folk laughing at the problem because of some variation on, "it seems so obvious now". I see PR folk bitter and annoyed because to them there is clearly something different that is not easy to delineate.
I see all this and more. We aren't winning any games of "I mapped it better" by mushing two categories together.
I'm generally sympathetic to the postrationalists on several points, but I agree with this. Coming up with the whole postrationality label was a bad idea in the first place, as it tends to serve tribal purposes and distracts people from the ways in which postrationality is just a straightforward extension of standard rationality.
(Ironically, one could argue that I already fit the criteria of "postrationalist", making it slightly weird for me to say that I'm sympathetic to the postrationalists, rather than being one of them. But to some extent I don't want to identify as post-rat, exactly because I don't think that post-rat is a good term and that good rat is already post-rat.)
There are definitely rationalist positions that have unexamined potential in the pr direction, where a good excuse is, "I haven't looked yet". (and a bad excuse might be, "that's dumb I don't want to look there"). In that sense there is rationality that is not yet at Post-rational investigations.
I had to have some sense and experience of investigating and knowing the world before I turned that machine on itself and started to explore the inner workings of the investigation mechanism.
While "rationality" claims to be defined as "stuff that helps you win", and while on paper if it turned out that the Sequences didn't help you arrive at correct conclusions we'd stop calling that "rationality" and call something else "rationality", in practise the word "rationality" points at "the stuff in the Sequences" rather than the "stuff that helps you win", and that people with stuff that helps you win that isn't the type of thing that you'd find in the Sequences have to call it something else to be unambiguous. Such is language.
The central claim of the Sequences is that what they expound is the stuff that helps you come to true beliefs and effective actions. It seems to me that that claim is well-founded. All the specific things I've seen touted as "Here's where 'rationality' is wrong" have always seemed to me to either be addressed in the Sequences already, or to be so confused that even the writer can't explain them. And all the things that do go beyond the Sequences (e.g. CFAR workshops -- about which I have no detailed knowledge) do not brand themselves in opposition as "post-rationality", any more than "applied mathematics" would be called "post-mathematics".
David Chapman, to take one major example, is pretty oppository in his prospectus for his proposed book "In the Cells of the Eggplant". I expect he would call it "extending", but it's more like hacking off all the limbs to replace them with tentacles.
My impression is that Chapman is objecting to a different kind of rationality, which he defines in a more specific and narrow way. At least, on several times in conversation when I've objected to him that LW-rationality already takes into account postrationality, he has responded with something like "LW-rationality has elements of what I'm criticizing, but this book is not specifically about LW-rationality".
Am I using the concept of expected value correctly in the following thought experiment?
I have a machine. I currently believe that there is a 50-50 chance it is broken. I know that buying a new one will cost $329.
If I buy a new one right now, there's no chance I'll get evidence out of thin air that the old one is actually fine so the expected value is $329*100%=$329.
If I spend $5.45, I can get enough evidnece to either put an end to the question or give me a 70% chance that the machine is really broken. Now the expected value calculation is $5.45*.5 = $2.73 if the machine was fine all along or ($329+5.45)*.5=$167.23 if I race off and buy a new machine. Adding the two, I get $169.96.
Finally, I can spend $75 on a fancy test that will conclusively say if the machine is broken. The expected value for "machine was fine all along" if I get this far is ($5.45+$75) * .3=$24.14 or $286.62 if my machine turned out to need replacing with a total cost of $310.76.
It feels right to me that the cost of doing the simple test is a much smaller number than assuming the machine is broken but is it really right to say that the cost of all gathering all the extra evidence & buying a new machine is still cheaper than buying the machine without doing the extra testing?
Extra conjecture: The answer is "Yes" because if I do all the extra work, there's lots of chances for me to branch off into the outcome of "Oh, that machine was fine all along" and stop right there.
I'm finishing up Nozick's big book 'o philosophy (mostly motivated by spite at this point), and I ran into an interesting misunderstanding of reductionism, disguised as a misunderstanding of physics.
Here's the whole quote:
To explain why something has a certain feature or property, we can refer to something else with that property, but a fundamental explanation of (the nature of) the property, or what gives rise to it or how it functions, will not refer to other things with the very same property; the possession and functioning of that property is what is to be explained, not only in this instance but in all its occurrences. This point was made by the philosopher of science N. R. Hanson, who pointed out that we should expect atoms and subatomic particles to lack the features that they fundamentally explain - only something itself colorless could constituted a fundamental explanation of color.
Ignore the philosophy for a second, and think about the science - are atoms colorless? No! Very no! They are colored in exactly the mundane way that everything is, which is rather the entire point.
The conclusion being false, then, what's wrong with the premises? Are you really allowed to use colored things in a reductionist explanation of color?
Turns out, yes you are. It's perfectly fine for the fundamental things to be colored. As long as none of the fundamental things are color itself, it's fine. We explain the orangeness of sodium lamps in terms of orange sodium atoms, and we explain the orangeness of sodium atoms in terms of properties (energy levels) that are not color. But the properties are, in a sense, just part of our map, just bookkeeping, and the actual stuff, the atoms, remain orange.
Perhaps Nozick knew this, and was just being a bit broad with the word "things." But given the scientific howler of an example, I'm not sure. Also, the rest of this chapter is basically just him making the same mistake repeatedly, except rather than "Reductionist explanation of color means modeling the world as made of colorless things," it's "reductionist explanation of values means modeling the world as made of valueless things."
This doesn't sound howlingly wrong, until you remember that he's going to pull the "and therefore reductionists think atoms are literally colorless" thing on you once or twice per paragraph.
Ignore the philosophy for a second, and think about the science—are atoms colorless? No! Very no! They are colored in exactly the mundane way that everything is, which is rather the entire point.
I don’t think I follow. What is this “mundane way” in which everything, and also atoms, is colored? As far as I can tell, atoms aren’t colored. Are you using “colored” and “colorless” in some unusual way?
Do we have multiple pictures of atoms that are different colors? Is there a link to more context that clarifies if this picture has anything to do with visible light vs an arbitrary way of displaying information after-the-fact?
(Intended as serious question, not a gotcha. I don't know much about how we look at atoms)
Here is some info about that picture:
A blue-violet laser blasts the atom, which then absorbs and re-emits enough light particles to be photographed with conventional equipment. So, technically, you’re seeing light emitted from an atom and not the atom itself.
[emphasis mine]
(from Photographed: The Glow from a Single, Hovering Strontium Atom)
Nadlinger took the photo by peering through a window of the ion trap's ultra-high vacuum chamber. He also used a 50 mm lens, extension tubes, and two flash units outfitted with color gels. Extension tubes are generally used for close-up photography.
Atoms are infinitesimally small, measuring only a miniscule fraction of an inch in diameter. At 38 protons and 215 billionths of a millimeter across, strontium atoms are relatively large by comparison. Still, the only reason why we can see the atom in the photo is because it absorbed and then re-emitted laser light at a speed capturable by a long camera exposure. So, the photo is actually of the laser light being re-emitted, rather than the outline of an atom. Without the long exposure effect, the atom wouldn't be visible to the naked eye.
[emphasis mine]
(from How a Student Took a Photo of a Single Atom )
To be clear, Nadlinger said, the purple speck at the center of this photo is not the true size of the strontium atom itself; it's the light from an array of surrounding lasers being re-emitted by the atom. When bathed in a specific wavelength of blue light, strontium creates a glow hundreds of times wider than the radius of the atom itself (which is about a quarter of a nanometer, or 2.5x10 to the -7 meters, Nadlinger said). This glow would be barely perceptible with the naked eye but becomes apparent with a little camera manipulation.
"The apparent size you see in the picture is what we'd call optical aberration," Nadlinger said. "The lens we're seeing it through is not perfect — also it's slightly out of focus and slightly overexposed. You could compare it to looking at the stars in the night sky, which appear bright but are actually much, much smaller than the size they seem to be, just because our eyes (or the camera) don't have enough resolution to process them."
So, seeing a single atom with the naked eye is impossible. Trapping one in a lab, however, is a little more doable.
[emphasis mine]
(from How a Student Photographed a Single Atom With a Store-Bought Camera)
So, technically, you’re seeing light emitted from an atom and not the atom itself.
Hm. Not sure you want to pick this reporter as your example of philosophical sophistication. Next.
Without the long exposure effect, the atom wouldn't be visible to the naked eye.
I think this is an important caveat in the context of talking about how the photograph was taken - a long exposure (on the order of 10 seconds) was used to capture the atom, and then a flash was used to illuminate the surroundings. Without this technique, the atom would not be visible in an image that also included the surroundings. What it is not, however, is a pronouncement on the inherent invisibility of atoms. But the next quote is.
So, seeing a single atom with the naked eye is impossible.
Congrats, you found a reporter saying the thing. However, this random reporter's opinion isn't necessarily true. To be honest, I'm not really sure if an atom really is visible to the naked eye (at least not as a continuous object, since humans can detect even single photons but only stochastically), or if you'd need binoculars to see it. Let's do some math. From here, let's suppose our trapped atom emits 20 million photons per second, spread across all angles. The faintest visible stars are about magnitude +6. How many photons per second is that?
Well, the sun shines down with about 1000 W/m^2 and it's magnitude -27. Since magnitude is a logarithmic scale, this means a magnitude +6 star shines about 6 × 10^-11 W/m^2 on us.
For the 400nm light used in the stackexchange comment, 20 million photons per second is just about 10^-11 Watts. This means that the surface of the sphere around the atom is only allowed to be 1/6th of a m^2, which means radius of 12 cm (about 5"). So if you were to put your eye 12 cm away from the atom, it would be as bright as the faintest stars humans can see in the sky. Farther than that and I'm happy to agree you couldn't see it with your naked eye.
You’re cherry-picking individual sentences out of what I quoted and ignoring the context, despite that context being right there in my comment. Please don’t do that.
Hm. Not sure you want to pick this reporter as your example of philosophical sophistication. Next.
What does philosophical sophistication matter? Are the quoted facts false? Is “A blue-violet laser blasts the atom, which then absorbs and re-emits enough light particles to be photographed with conventional equipment” a lie?
… a long exposure (on the order of 10 seconds) was used to capture the atom, and then a flash was used to illuminate the surroundings. Without this technique, the atom would not be visible in an image that also included the surroundings. What it is not, however, is a pronouncement on the inherent invisibility of atoms.
Why does it need to be such a pronouncement? You linked the strontium atom photograph as evidence for your claim that I could look at an atom and see what color it is. But said photograph is not, in fact, evidence for that claim, as my links and quotes explain.
Your one piece of provided evidence being disqualified, do you have any other evidence for your claim? If not, then we’re back to my answer: no, I cannot look at an atom someone hands me and see what color it is. (And while we’re at it, how exactly do you propose that someone “hand me an atom”, anyhow? I let this part slide before, but since we’re nitpicking…)
Congrats, you found a reporter saying the thing. However, this random reporter’s opinion isn’t necessarily true.
What about the facts that reporter reports? Are they true? Or do you claim that reporter was lying about some or all of the following:
the purple speck at the center of this photo is not the true size of the strontium atom itself
When bathed in a specific wavelength of blue light, strontium creates a glow hundreds of times wider than the radius of the atom itself (which is about a quarter of a nanometer, or 2.5x10 to the −7 meters, Nadlinger said).
This glow would be barely perceptible with the naked eye but becomes apparent with a little camera manipulation.
“The apparent size you see in the picture is what we’d call optical aberration,” Nadlinger said.
Which of these are false?
To be honest, I’m not really sure if an atom really is visible to the naked eye … Let’s do some math. … [math snipped] … So if you were to put your eye 12 cm away from the atom, it would be as bright as the faintest stars humans can see in the sky. Farther than that and I’m happy to agree you couldn’t see it with your naked eye.
I am not a physicist and cannot evaluate your math or your claims. Do you have some citation, to some reliable source (or preferably multiple such, but one will do for now) confirming that atoms are visible with the unaided naked eye? And, do you have any examples you can cite of humans seeing individual atoms with their unaided vision?
(It would also help somewhat if other physics-knowledgeable Less-Wrongers would comment on whether this math makes sense—and why, if it does make sense, it seems to contradict the reporting of the facts surrounding the strontium atom demonstration.)
What does philosophical sophistication matter? Are the quoted facts false? Is “A blue-violet laser blasts the atom, which then absorbs and re-emits enough light particles to be photographed with conventional equipment” a lie?
The sentence you quote is true. And "The sun blasts the cover of the book, which then absorbs and re-emits photons to be photographed with conventional equipment" is an equally valid description of taking a picture of a book. I'm honestly confused as to what you're expecting me to find inconsistent here. Are you implying that since you can describe scattering of light using scientific talk like "photons" and "re-emission," you can't describe it using unscientific talk like "the atom was purple?"
Ah, or maybe you're expecting me to know that you mean something like "What if the atom is only purple because it's being 'blasted' with purple photons, making this photo useless in terms of understanding its color?" That's a reasonable thing to think if you've never had reason to study atomic spectra, but it turns out the direction of causation is just the opposite - scientists chose a purple laser because that's one of the few colors the atom would absorb and re-emit.
I think what this shows is that my perception of what's "everyday" has definitely been skewed by a physics degree, and things that just seem like the way everything works to me might seem like unusual and rare sciencey phenomena to everyone else.
Like, you ask me to refute this fact or that fact, but I already quoted precisely the statements I thought deserved highlighting from the articles, and none of them were facts about how light or atoms work. That should tell you that I have zero intention of overthrowing our basic understanding of optics. But since we might have different understandings of the same sentences, I will go through the specific ones you highlight and try to read your mind.
the purple speck at the center of this photo is not the true size of the strontium atom itself
This is due to the limitations of the camera - even if the light came from a single point, the camera wouldn't be able to focus it back down to a single pixel on the detector. This is due to a combination of imperfections in the lenses plus physics reasons that make all pictures a little blurry. The same thing happens in the human eye - even if we were looking at a point source of purple light, it would look to our eye like a little round dot of purple light.
Mind reading: Maybe you are implying that if the camera can't resolve the true size of the atom, it's not "really" a picture of the atom. This is sort of true - if the atom was blue on the left and red on the right (let's ignore for a moment the physical impossibility), it would still look purple in this photo despite never emitting purple photons. Of course, we do know that it emits purple photons. But I think the thing that is actually mistaken about worrying about whether this is "really" the atom is that it's forgetting the simplicity of just looking at things to tell what color they are.
Even when I argue that things invisible to the planet eye, like the planet Neptune, can have color, it's not necessarily because of complicated sciencey reasoning, but more some heuristic arguments about process that preserve color. You can look at Neptune through a telescope and it has color then - so since telescopes preserve color, Neptune is blue. Or if I took a red teapot and shot it into space somewhere between the orbit of Mars and Jupiter and we never saw it again, it would still be red, because in color-logic, moving something somewhere else is a process that preserves color.
In short, I didn't bother to actually do the math on whether you could see an atom with the naked eye until today because I think of time lapse photography or using lenses to look at something as process that preserve "intuitive color."
When bathed in a specific wavelength of blue light, strontium creates a glow hundreds of times wider than the radius of the atom itself (which is about a quarter of a nanometer, or 2.5x10 to the −7 meters, Nadlinger said).
I'm not sure what the reporter is getting at here. I think they are comparing the wavelength of the light to the electron radius of the atom, and the wavelength of the light is what they mean by "creates a glow." It's definitely inaccurate. But I'm not sure I could do better to explain what's going on to an audience that doesn't know quantum mechanics. Maybe a water analogy? The atom emitting a photon is like a tiny stone tossed into a pond. The size of the ripples emitted by the tiny stone is a lot bigger than the size of the stone itself.
Mind reading: Maybe you read this as something like "We're not actually seeing the atom, we're just seeing 'a glow created by the atom' that's a lot bigger than the atom, therefore this isn't a picture of the atom." That's false. This goes back to why I was making fun of the reporter who said "We're not seeing the atom, we're just seeing the light emitted by the atom." Seeing the light emitted by something is what seeing is. You could just as well say "I'm not actually seeing my hand, I'm just seeing the light emitted by my hand," and you'd be just as wrong. Learning about photons should not destroy your ability to see things, and if it does you're doing philosophy very wrong.
This glow would be barely perceptible with the naked eye but becomes apparent with a little camera manipulation.
Yup, this is that "long exposure to the atom + short flash of the surroundings" technique I talked about in the previous comment. Maybe you see the word "manipulation" and assume that everything is meaningless and this "doesn't count"? I think this question stops being useful when you understand what was actually done to get the photo.
“The apparent size you see in the picture is what we’d call optical aberration,” Nadlinger said.
See above about the limitations of cameras.
I am familiar with the physical facts you’ve described in this comment. But, what seems to be the case is that you are confused about what color is.
For example:
Of course, we do know that it emits purple photons.
There is no such thing as “purple photons”. (If you doubt this, consider whether there’s such a thing as “magenta photons”—and if not, why not, if there can be “purple photons”—and also whether, when you look at a picture of an orange on your computer, the computer’s screen is emitting “orange photons”.)
Ah, or maybe you’re expecting me to know that you mean something like “What if the atom is only purple because it’s being ‘blasted’ with purple photons, making this photo useless in terms of understanding its color?” That’s a reasonable thing to think if you’ve never had reason to study atomic spectra, but it turns out the direction of causation is just the opposite—scientists chose a purple laser because that’s one of the few colors the atom would absorb and re-emit.
What would the atom look like in ordinary illumination (say, sunlight at noon, or a flourescent light, or any other common lighting conditions)? Would it also look purple?
Even when I argue that things invisible to the planet eye, like the planet Neptune, can have color, it’s not necessarily because of complicated sciencey reasoning, but more some heuristic arguments about process that preserve color. You can look at Neptune through a telescope and it has color then—so since telescopes preserve color, Neptune is blue. Or if I took a red teapot and shot it into space somewhere between the orbit of Mars and Jupiter and we never saw it again, it would still be red, because in color-logic, moving something somewhere else is a process that preserves color.
In short, I didn’t bother to actually do the math on whether you could see an atom with the naked eye until today because I think of time lapse photography or using lenses to look at something as process that preserve “intuitive color.”
There is no fact of the matter about whether Neptune “is blue”. The physical facts which sentences like “a tomato is red” or “a banana is yellow” cash out into, are inapplicable to Neptune. We could say that Neptune “looks blue when viewed with the naked eye from Earth”—which would be false, because Neptune cannot be seen with the naked eye from Earth. We could also say that Neptune “looks blue when viewed through a telescope from Earth”—which would be true.
So, is a strontium atom purple? Well, let’s table that. Does a strontium atom look purple when viewed with the unaided naked eye in ordinary terrestrial lighting conditons? No; it cannot be seen with the unaided naked eye. (Right? Or do you say that it can?) Does a strontium atom look purple when subjected to laser light of a certain frequency, etc.? No; it still cannot be seen with the unaided naked eye, even then. Does a picture of a strontium atom which has been subjected to certain light etc., taken with a certain sort of long-exposure camera, etc., look purple? Clearly, yes.
Maybe you read this as something like “We’re not actually seeing the atom, we’re just seeing ‘a glow created by the atom’ that’s a lot bigger than the atom, therefore this isn’t a picture of the atom.” That’s false. This goes back to why I was making fun of the reporter who said “We’re not seeing the atom, we’re just seeing the light emitted by the atom.” Seeing the light emitted by something is what seeing is.
(This part is also confused, but I defer commenting on it, as I would like you to address the other things I’ve said in this comment and prefer to avoid distractions; I merely note it for the record.)
(I'm coming to this rather late, and will entirely understand if Said doesn't want to resurrect an old discussion; if not, I hope no reader will take the lack of response to indicate that my points were just so compelling that Said had no answer to them.)
There is no such thing as “purple photons” [...]
I am unconvinced by your argument here (which may just indicate that I haven't grasped what it is). The following position seems pretty reasonable to me: There are violet photons but not magenta photons. There are orange photons, but because of metamerism you can see something orange without any orange photons being involved. Violet photons are not violet in the same way as a piece of paper covered in violet dye is violet, but it's reasonable to use the same word for both.
Would you care to make more explicit your reasons for saying that there is no such thing as a violet photon? (You actually said purple, as Charlie had done in the comment you were replying to, but I'm fairly sure your position is not "there are photons of some colours but not of others". My apologies if I've misunderstood.)
What would the atom look like in ordinary illumination [...]
Like many things, it would look different in different conditions of illumination. Unlike most things we look at, its spectrum is composed of a few sharp peaks, so the relationship between its illumination and the colour we see (given sufficient "amplification" since of course a single atom can neither emit nor scatter very much light) is a bit unusual. (One can make macroscopic materials with similar properties and I don't see any particular reason to deny that they have colour.)
There is no fact of the matter as to whether Neptune "is blue". [...]
This seems like a matter of definitions, and I don't like your definitions. Whatever difficulties there are about assigning a colour to Neptune are simple a consequence of the fact that it's a long way away from us. (I think it's clear that there's a fact of the matter as to whether Mars is red: it is. If Neptune's orbit were where Mars's is, there'd be no difficulty saying that Neptune is blue.) Are you sure you want to say that whether a thing has a definite colour can change merely on account of the distance between it and us? If we sent astronauts to Neptune instead of just probes, would there then be a fact of the matter as to whether Neptune has a colour? If there were an accident and the astronauts died, would Neptune's colour-having-ness change? If I take an orange, lock it in a vault (illuminated, let's say, by an incandescent bulb in the vault), and throw away the key, does there stop being a fact of the matter as to whether the orange is orange?
Incidentally: yes, the reporter is wrong about something. A quarter of a nanometre is not 2.5 x 10^-7 metres.
Well, you are free to use the word "color" in such a way that there is no fact of the matter about whether Neptune has a color if you wish. But I think that this directs us into a definitional argument that I don't feel like having - in fact, almost a perfect analogy to "If a tree falls in a forest and there's no one to hear it, does it make a sound?"
So yeah, it's been fun :)
No, this isn’t a definitional argument. Insofar as your view leads you to misunderstand very real facts about human color perception, it is mistaken. Again, consider the questions I asked about “photon color” at the start of the grandparent comment.
This sort of misconception is quite common, especially among mathematically or physically inclined folks who have not studied color theory and the psychophysics of color. It leads, unfortunately, to mistakes in the design and implementation of various systems that have to use or manipulate color in one way or another.
It’s certainly your right to tap out of the conversation. But I hope that you’ll consider what I’ve said (and the same goes for anyone else reading this exchange who feels that Charlie Steiner’s perspective makes sense).
Trapped atoms are always illuminated by a laser that picks out one single wavelength emitted by the atom. This isn't necessarily the same color you'd see if these atoms were scattering sunlight - in addition to the color used in the lab, you might see a few other wavelengths as well, along with a generic bluish color due to Rayleigh scattering. But since each atom emits / absorbs different wavelengths, each will look different both under sunlight and when trapped in the lab.
Here's an example of trapped atoms emitting green light - figure 3 is a photo taken through an optical microscope: https://arxiv.org/ftp/arxiv/papers/0908/0908.0174.pdf
That link does not demonstrate anything like what you seem to be claiming it does.
Edit: See my reply to Raemon for details.
If sodium is intrinsically orange, why is sodium chloride white? There are a number of explanations of colour in terms of the behaviour of photons and electrons.. and the behaviour of sodium in a plasma is not the same as its behaviour in a NaCl molecule, but which is why salt isn't orange... and none of these explanations eave colour as a fundamental quality.
I don't know why you think "actual stuff" stops at atoms. What, then, are the components of atoms?
Try inverting the claim that you can explain a property in terms of itself. If I say that some things are good because they have a property of goodness, have I reduced the concept of "good".
If sodium is intrinsically orange, why is sodium chloride white?
Are you expecting an answer other than the obvious one? Are you just trying to smuggle fundamental color back into the question by using the word "intrinsically?"
Try investing the claim that you can explain a property in terms of itself.
Are you willfully misreading me, or is it just accidental?
Are you willfully misreading me, or is it just accidental
Consider the possibility that you are not being as clear as you think you are.
l'm responding to your:-
are atoms colorless? No! Very no! They are colored in exactly the mundane way that everything is, which is rather the entire point.
Consider the possibility that you are not being as clear as you think you are.
Fair enough.
are atoms colorless? No! Very no! They are colored in exactly the mundane way that everything is, which is rather the entire point.
Maybe it would help if I said that atoms are non-fundamentally colored, in exactly the same way that a chair, or grass, or the sky is non-fundamentally colored. The everyday meaning of "the grass is green" or "the sun is yellowish-white" extends nicely down to the atomic scale. Even a free electron (being a thing that scatters light) has a color.
When you make a reductionist explanation of color, it's the explanation that lacks color, not the atoms.
Does the sun smell? Technically probably yes. But I'd call it a relative context error to be taking the question too seriously.
Does a "particle smaller than the wavelength of the visible light spectrum produce radiation in the visible light spectrum inherently?" - sounds like a very strange question to me.
"Is a chair a chair?" - "does this specific (central) example of the category chair represent the full global universal diversity of the category chair?"
If said like that, we've dissolved a confusion. There are still koan like questions designed for something else but these are not them.
Let's talk about standard temperature and pressure. Having an atmosphere would help to standardise colour.
Being embedded in a molten liquid sodium would change the way we ask this question. So would gaseous molecules.
How many assumptions underly the question. Earth based biological humanoid (as opposed to cat, bee, dog, squid) to define visible to human.
What are we trying to say with our categories and why?
Maybe it would help if I said that atoms are non-fundamentally colored, in exactly the same way that a chair, or grass, or the sky is non-fundamentally colored
That may be true, but it isn't a refutation of the claim that "when the reductive explanation of property P hits its basic level, property P is no longer found", because atoms are not "fundamental things", not the basis of the reductive explanation of matter: electrons and photons are.
Even a free electron (being a thing that scatters light) has a color
What colour is an electron? There is no answer to the question "what is the colour of an electron", because electrons are basic in the reductive explanation of colour. How an electron scatters photons is behaviour that depends on context.
If you cover a brown chair with blue paint, it becomes a blue chair. There is no answer to the question "What color is a chair?", because how a chair scatters light depends on context.
Chairs are non-fundamentally colored, so the only question you can even try to answer is "What color is this chair?"
Y'all are trying to rely on a dichotomy between "Fundamental particles are fundamentally colored" and "Fundamental particles have no color." That is a false dichotomy. The color of an electron depends on context - congrats, you have shown that it is not fundamentally colored, we agree.
Are you sure that post rationality is opposite to rationality? Where did that idea come from?
I've been involved in the loosely defined PR cluster for a while and I've not seen such a thing yet. Do you have a link?