1

Alice: My favorite color is green.

Bob: Oh, cool. Mine's red.

Months later...

Bob: Hey, I got you this green painting. I remember you saying your favorite color is green and I thought you'd like it.

Alice: Oh. Um, that's nice of you, but I actually don't really like green. My favorite color's not green — it's blue.

Bob: Oh. I coulda sworn you had said green.

Alice: Oh, I think I did say green. But, um, Bob... you really shouldn't take things people say so literally all of the time.

Bob: Blinks. I'm confused.

Alice: Ok. Well, I mean, yeah, I think I did say green. But, like, I was just kinda gesturing at the area where my favorite color is. And I obviously didn't mean, like, literally green.

Bob: Obviously?

Alice: Yeah. Green is a secondary color. Who chooses a secondary color as their favorite color. My favorite color is obviously going to be a primary color.

Bob: Ok. That was quite far from being obvious to me, but ok. But — and I have a feeling you're going to accuse me of being too analytical for saying this — but even if I infered that your favorite color must actually be a primary color, wouldn't it still be ambiguous whether it's blue or yellow?

Alice: Ugh. Sorry, but yeah, you are being too analytical. Sure — if you want to be technical about it, yes, green is equidistant from blue and from yellow if you look at hue angles on a color wheel. But why would you look at hue angles on a color wheel! We're humans!

Bob: I wish I understood what you mean.

Alice: Ok. At least in my experience, like, yellow is kinda gross. I mean, who's favorite color is yellow? Blue is clearly a much more aesthetically pleasing and likable color.

2

Carol: My favorite color is green.

Dave: I'm sorry — green? Just, green?

Carol: Uh, yeah. Why... you seem confused?

Dave: I mean, that just isn't very precise. It could mean so many different things. People measure color in various ways — wavelength, hue, physiological encodings, whatever. But whichever model you pick, just saying "green" only tells me so much.

Carol: Ok, now I'm confused.

Dave: Well, there's a blog post called The Virtue of Narrowness that you really should read, but I'll elaborate. Imagine a space of all possible colors. When you said "green", you drew a circle around a set of — let's call them points — a set of points in color space. This set contains many, many, many points, and so you failed to effectively zero in on the concept you were intending to convey to me, which is poor communication.

Carol: I —

Dave: Eliezer has a blot post called Mundane Magic where he dives into an adjacent idea that you may find to be helpful. He refers to speaking as "vibratory telepathy". You see, when we speak, we vibrate air molecules in such a way where one person — the "sender", we can call them — shares a thought with the other person, the "receiver". So by vibrating air molecules, you can actually take a mind-state in one person and cause a second person to experience that same mind-state. It's pretty cool.

Carol: I think I see —

Dave: And your failure was that, in the way you vibrated those air molecules, it didn't actually allow me to experience the same mind-state as you. You should have vibrated them in a different way. A way that —

Carol: Dave! Slow down a second. I sorta get what you mean, but this is getting very abstract.

Dave: Ok, I think I can dumb it down for you. Sorry.

Carol: I —

Dave: Ok, imagine that you ask me where I live. With me so far?

Carol: Sure.

Dave: Good. And imagine that I just say... "the United States".

Carol: Ok.

Dave: Cool, you're doing good. That wouldn't be very helpful... would it?

Carol: It depends on why I am asking the question, but sure — I agree that it wouldn't be very helpful.

Dave: Good.

Carol: Blinks.

Dave: Well? Do you not see the parallel? I don't know how to — you basically just told me that your favorite color is "the United States".

Carol: Actually, I think what I told you is that my favorite color is Portland.