Each observed emerald is evidence for both “the emerald is green” and “the emerald is grue.” The first is preferred because it is vastly simpler (and picking any particular T, of course, is hugely privileging the hypothesis!) Evidence that is equally strong for two propositions doesn’t change their relative likelihoods—so it starts out more likely that the emeralds are green than grue, and it ends more likely that the emeralds are green than grue, but both are quickly more likely than the proposition that emeralds are uniformly red.
If someone was brought up from birth with the words “grue” and “bleen,” how would they say something was “green,” in their language? Well, they’d have to say that something was grue before, say, 2050, but bleen after. Something that changes from grue to bleen is clearly more complicated to write down than something that just stays grue all the time.
And this is just hiding the complexity, not making it simpler. Complexity isn’t a function of how many words you use, cf. “The lady down the street is a witch; she did it.” If we are writing a program that emits actual features of reality, rather than socially defined labels, the simplest program for green is simpler than the simplest program for grue or bleen. That you can also produce more complex programs that give the same results (defining green in terms of bleen and grue is only one such example) is both trivially true and irrelevant.
Wait, actually, I’d like to come back to this. What programming language are we using? If it’s one where either grue is primitive, or one where there are primitives that make grue easier to write than green, then true seems simpler than green. How do we pick which language we use?
Well, they’d have to say that something was grue before, say, 2050, but bleen after.
This is a trick of definition only, however. Changing the definition does not cause those things affected by the old definition to conform to the new one.
What’s weird, is that without a premise about what “green” and “blue” stand for semantically, the skeptic can just repeat that paragraph back to you, but switch all the occurrences of “grue” and “green”, since “grue” and “green” are logically symmetrical.
It seems to me that the only sensible primitives are photons, which have particular energies. A perception system that has two sets of mappings from energies to names and a clock is necessarily less simple than a perception system that has one mapping from energies to names.
The theory holds that the world consists of ultimate logical “facts” (or “atoms”) that cannot be broken down any further.
(from wikipedia) For “green” to be atomic, that suggests it cannot be broken down. Are you suggesting that “green” cannot be broken down to statements about energies of photons?
No, I just mean that (or goodman just means that) if we assume the meanings of grue and bleen, then we have to define green in terms of grue and bleen and a time interval.
But where can I find grue and bleen? If knowledge of them were deleted from my memory, would I reform those concepts?
If you deleted my knowledge of color, but left me my eyes, I could still distinguish between photons of 2.75 eV and photons of 2.3 eV. That’s a difference you can find outside you and that persists.
But where can I find grue and bleen? If knowledge of them were deleted from my memory, would I reform those concepts?
If you were a confused philosopher then yes, you probably would! It’s definitely part of thought-space that I expect people to rush to fill once they are spending their time thinking of pointless stuff. Hopefully if it was you you would proceed straight to dissolving the question!
The problem seems trivially easy.
Each observed emerald is evidence for both “the emerald is green” and “the emerald is grue.” The first is preferred because it is vastly simpler (and picking any particular T, of course, is hugely privileging the hypothesis!) Evidence that is equally strong for two propositions doesn’t change their relative likelihoods—so it starts out more likely that the emeralds are green than grue, and it ends more likely that the emeralds are green than grue, but both are quickly more likely than the proposition that emeralds are uniformly red.
What’s weird about this?
To clarify what potato said:
If someone was brought up from birth with the words “grue” and “bleen,” how would they say something was “green,” in their language? Well, they’d have to say that something was grue before, say, 2050, but bleen after. Something that changes from grue to bleen is clearly more complicated to write down than something that just stays grue all the time.
And this is just hiding the complexity, not making it simpler. Complexity isn’t a function of how many words you use, cf. “The lady down the street is a witch; she did it.” If we are writing a program that emits actual features of reality, rather than socially defined labels, the simplest program for green is simpler than the simplest program for grue or bleen. That you can also produce more complex programs that give the same results (defining green in terms of bleen and grue is only one such example) is both trivially true and irrelevant.
Wait, actually, I’d like to come back to this. What programming language are we using? If it’s one where either grue is primitive, or one where there are primitives that make grue easier to write than green, then true seems simpler than green. How do we pick which language we use?
Agreed.
This is a trick of definition only, however. Changing the definition does not cause those things affected by the old definition to conform to the new one.
Obviously they’d have to invent a new word, for an object that emits light that causes certain kind of qualia.
What’s weird, is that without a premise about what “green” and “blue” stand for semantically, the skeptic can just repeat that paragraph back to you, but switch all the occurrences of “grue” and “green”, since “grue” and “green” are logically symmetrical.
They can claim that the grue hypothesis is simpler than the green hypothesis?
If we take “green” and “bleen” as primitives, then it is the definition of “green” which requires the time interval, not grue.
But if we go down to the level of photons, “green” and “blue” don’t require a time interval in their definitions, yet “grue” and “bleen” do.
What do you mean by “primitives”?
It seems to me that the only sensible primitives are photons, which have particular energies. A perception system that has two sets of mappings from energies to names and a clock is necessarily less simple than a perception system that has one mapping from energies to names.
logical primitives, look up logical atomism, take it with a grain of salt.
(from wikipedia) For “green” to be atomic, that suggests it cannot be broken down. Are you suggesting that “green” cannot be broken down to statements about energies of photons?
No, I just mean that (or goodman just means that) if we assume the meanings of grue and bleen, then we have to define green in terms of grue and bleen and a time interval.
But where can I find grue and bleen? If knowledge of them were deleted from my memory, would I reform those concepts?
If you deleted my knowledge of color, but left me my eyes, I could still distinguish between photons of 2.75 eV and photons of 2.3 eV. That’s a difference you can find outside you and that persists.
right, thats the point, to solve the problem, you have to move into semantics.
If you were a confused philosopher then yes, you probably would! It’s definitely part of thought-space that I expect people to rush to fill once they are spending their time thinking of pointless stuff. Hopefully if it was you you would proceed straight to dissolving the question!
You mean grue and bleen?
But… why would we be allowed to do that?