Would I somehow feel this problem less acutely if I had never been taught Fahrenheit, Celcius, or Kelvin; and instead been told everything in terms of gigabytes per nanojoule? I guess probably not. Inconvenient conversions are not preventing me from figuring out the relations and benchmarks I'm interested in.

It's important to remember, though, that I will be fine if I so choose. After all, if the scary impression was the real thing then it would appear scary to everyone.  

Reading this makes me feel some concern. I think it should be seriously asked: Would you be fine if you hypothetically chose to take a gap year or drop out? Those didn't feel like realistic options for me when I was in high school and college, and I think this ended up making me much less fine than I would have been otherwise. Notably, a high proportion of my close friends in college ended up dropping out or having major academic problems, despite being the smartest and most curious people I could find.

My experiences during and after college seemed to make a lot more sense after hearing about ideas like credential inflation, surplus elites, and the signaling model. It seems plausible that I might have made better decisions if I had been encouraged to contemplate those ideas as a high schooler.

In measuring and communicating about the temperature of objects, humans can clearly and unambiguously benchmark things like daily highs and lows, fevers, snow, space heaters, refrigerators, a cup of tea, and the wind chill factor. We can place thermometers and thereby say which things are hotter than others, and by how much. Daily highs can overlap with fevers, but neither can boil your tea.
 

But then I challenge myself to estimate how hot a campfire is, and I'm totally stuck.

It feels like there are no human-sensible relationships once you're talking about campfires, self-cleaning ovens, welding torches, incandescent filaments, fighter jet exhaust, solar flares, Venus, Chernobyl reactor #4, the anger of the volcano goddess Pele, fresh fulgurites, or the boiling point of lead. Anything hotter than boiling water has ascended into the magisterium of the Divinely Hot, and nothing more detailed can be said of them by a mortal. If I were omnipotent, omniscient, & invulnerable, then I could put all those things in contact with each other and then watch which way the heat flows. But I am a human, so all I can say is that anything on that list could boil water.

Presumably he understood the value proposition of cryonics and declined it, right?

If everyone in town magically receives the same speedup in their "verbal footwork", is that good for meta-honesty? I would like some kind of story explaining why it wouldn't be neutral.

Point for yes: 
Sure seems like being able to quickly think up an appropriately nonspecific reference class when being questioned about a specific hypothetical does not make it harder for anyone else to do the same.

Point against: 

The code of literal truth only lets people navigate anything like ordinary social reality to the extent that they are very fast on their verbal feet, and can respond to the question "How are you?" by saying "Getting along" instead of "Horribly" or with an awkward silence while they try to think of something technically true.

This particular case seems anti-inductive and prone to the euphemism treadmill. Indeed, one person one time can navigate ordinary social reality by saying "Getting along" instead of giving an awkward silence; but many people doing so many times will find that it tends to work less well over time. If everyone magically becomes faster on their verbal feet, they can all run faster on the treadmill, but this isn't necessarily good for meta-honesty.

Implications: either cognitive enhancement becomes even more of a moral priority, or adhering to meta-honesty becomes a trustworthy signal of being more intelligent than those who don't. Neither outcome seems terrible to me, nor even all that much different from the status quo.

Glad to see some discussion of social class.

Here's something in the post that I would object to:

Non-essential weirdnesses, on the other hand, should be eliminated as much as possible because pushing lifestyle choices onto disinterested working-class people is a misuse of class privilege. Because classes are hierarchical in nature, this is especially important for middle-upper class people to keep in mind. An example of non-essential weirdness is “only having vegan options for dinner”.

This example seems wrong to me. It seems like serving non-vegan options does in fact risk doing a great injustice (to the animals eaten). I tried and failed to think of an example that seemed correct, so now I'm feeling pretty unconvinced by the entire concept. 

One contrary idea might be that class norms and lifestyle choices are usually load-bearing, often in ways that are deliberately obscured or otherwise non-obvious. Therefore, one may want to be cautious when labeling something a non-essential weirdness. 

(Also maybe worth mentioning that I think class phenomena are in general anti-inductive and much harder to reach broad conclusions about than other domains.)

• Most people, even most unusually honest people, wander about their lives in a fog of internal distortions of reality. Repeatedly asking yourself of every sentence you say aloud to another person, "Is this statement actually and literally true?", helps you build a skill for navigating out of your internal smog of not-quite-truths. For that is our mastery.

I think some people who read this post ought to reverse this advice. The advice I would give to those people is: if you're constantly forcing every little claim you make through a literalism filter, you might end up multiplying disfluencies and generally raising the cost of communicating with you. Maybe put a clause limit on your sentences and just tack on a generic hedge like "or something" if you need to.

Only praise yourself as taking 'the outside view' if (1) there's only one defensible choice of reference class;

I think this point is underrated. The word "the" in "the outside view" is sometimes doing too much work, and it is often better to appeal to an outside view, or multiple outside views.

What do you think the internal experience of these liars is like? I could believe that some of them have gotten a lot of practice with fooling themselves in order to fool others, in settings where doing so is adaptive. Do you think they would get different polygraph results than the believer in the invisible dragon hypothetically would?