Silas, that’s actually a pretty good way to capture some of the major theories about color—ostensive definition for a given color solves a lot of problems.
But I wish Eliezer had pointed out that intensional definitions allow us to use kinds of reasoning that extensional definitions don’t … how do you do deduction on an extensional definition?
Also, extensional definitions are harder to interpersonally communicate using. I can wear two shirts, both of which I would call “purple,” and someone else would call one “mauve” and the other “taupe” (or something like that—I’m not even sure what those last two colors are). Whereas if we’d defined the colors on wavelengths of light, well, we know what we’re talking about. It’s harder to get more overlap between people on extensional rather than intensional definitions.
Mauve is a light grayish purple, reasonably likely to appear in the sky soon after sunset. Taupe is some sort of brown. I was bewildered by the top example at the wikipedia article—it’s much darker than what I think of as taupe. It turns out (page down a ways) that what I had in mind was sandy taupe—the Crayola version.
Silas, that’s actually a pretty good way to capture some of the major theories about color—ostensive definition for a given color solves a lot of problems.
But I wish Eliezer had pointed out that intensional definitions allow us to use kinds of reasoning that extensional definitions don’t … how do you do deduction on an extensional definition?
Also, extensional definitions are harder to interpersonally communicate using. I can wear two shirts, both of which I would call “purple,” and someone else would call one “mauve” and the other “taupe” (or something like that—I’m not even sure what those last two colors are). Whereas if we’d defined the colors on wavelengths of light, well, we know what we’re talking about. It’s harder to get more overlap between people on extensional rather than intensional definitions.
Mauve is a light grayish purple, reasonably likely to appear in the sky soon after sunset. Taupe is some sort of brown. I was bewildered by the top example at the wikipedia article—it’s much darker than what I think of as taupe. It turns out (page down a ways) that what I had in mind was sandy taupe—the Crayola version.