I’m going to agree with those saying that Thagard is missing the point of Putnam’s thought experiment. Below, I will pick on Thagard’s claim that Grisdale has refuted Putnam’s thought experiment. For anyone interested, Putnam’s 1975 article “The Meaning of “Meaning”″, and Grisdale’s thesis are both available as PDFs.
Thagard says that Grisdale has refuted Putnam’s thought experiment. What would it mean to refute a thought experiment? I would have guessed that Thagard meant the conclusion or lesson drawn from the thought experiment is wrong. But Grisdale himself says that Putnam’s conclusion was correct, even though it was “misleading.”
Incidentally, I’m not sure how a thought experiment gets the right answer (or gets the thought-experimenter to the right answer) and yet counts as misleading … but leave that for now.
Back to refuting a thought experiment. What does Grisdale actually do? As I read him, he lays out some reasons why Putnam’s thought experiment cannot be realized in the actual world. Now, if the success of Putnam’s thought experiment depended on its being realizable in the actual world, then Grisdale’s thesis would be a heavy blow to that thought experiment. (Though not necessarily to Putnam’s theory, as Grisdale concedes.)
But, the success of Putnam’s thought experiment does not depend on its being realizable in the actual world. In this way, it is similar to Newcomb’s problem and to various trolley problems. If I were able to push a fat man off of a bridge, that fat man would not be large enough to stop a runaway trolley capable of killing five other people; nonetheless, the thought experiment is useful and interesting. The thought experiment only serves to get you to imagine vividly the following abstract circumstance: A and B are people who belong to two different communities; there are two substances A and B that are superficially similar but have different micro-structures; the two communities use A and B for the same sorts of things; and when any member of community A refers to A he or she has the same internal mental state that a member of B has when he or she refers to B . Now, we are asked whether A and B mean the same thing by their respective words for A and B—whatever that word or those words happen to be.
If a more realistic, concrete case helps, consider jade, which Putnam briefly talks about in his 1975 paper. (What Putnam says about jade strikes me as right but also strikes me as exactly the opposite of what he should have said on the basis of his own theory!) Jade is not a single kind of stuff. Rather, there are two different minerals, jadeite and nephrite, that go by the name “jade” because they have a bunch of very similar macroscopic properties, even though they have very different micro-structures. We could imagine two communities—one that has only ever seen jadeite and one that has only ever seen nephrite. Now, suppose that Billy asks for some jadeite at his local market, and Suzy asks for some nephrite at her local market. And suppose that their concepts are identical. They are both thinking of a hard, waxy, precious stone with a greenish-white color. Do their words have the same meaning (for them)?
According to Putnam’s theory, the answer should be NO. If Billy were to discover a piece of nephrite and say that it was jadeite, he would be wrong. Why? In part because the micro-structure of the stuff that his community baptized as “jadeite” is nothing like the micro-structure of nephrite.
Now, I will not deny that for some thought experiments, the hypothetical may be usefully resisted. The Chinese Room is one such thought experiment. And, I agree that one could refute a thought experiment by disputing its premisses. For example, by showing that if the premisses are as they must be, the conclusion or lesson of the thought experiment changes. But when that works, it is because the premisses that are being disputed make a difference for the conclusion reached. In the case of Putnam’s H2O / XYZ thought experiment, the physical facts just don’t matter.
I’m going to agree with those saying that Thagard is missing the point of Putnam’s thought experiment. Below, I will pick on Thagard’s claim that Grisdale has refuted Putnam’s thought experiment. For anyone interested, Putnam’s 1975 article “The Meaning of “Meaning”″, and Grisdale’s thesis are both available as PDFs.
Thagard says that Grisdale has refuted Putnam’s thought experiment. What would it mean to refute a thought experiment? I would have guessed that Thagard meant the conclusion or lesson drawn from the thought experiment is wrong. But Grisdale himself says that Putnam’s conclusion was correct, even though it was “misleading.”
Incidentally, I’m not sure how a thought experiment gets the right answer (or gets the thought-experimenter to the right answer) and yet counts as misleading … but leave that for now.
Back to refuting a thought experiment. What does Grisdale actually do? As I read him, he lays out some reasons why Putnam’s thought experiment cannot be realized in the actual world. Now, if the success of Putnam’s thought experiment depended on its being realizable in the actual world, then Grisdale’s thesis would be a heavy blow to that thought experiment. (Though not necessarily to Putnam’s theory, as Grisdale concedes.)
But, the success of Putnam’s thought experiment does not depend on its being realizable in the actual world. In this way, it is similar to Newcomb’s problem and to various trolley problems. If I were able to push a fat man off of a bridge, that fat man would not be large enough to stop a runaway trolley capable of killing five other people; nonetheless, the thought experiment is useful and interesting. The thought experiment only serves to get you to imagine vividly the following abstract circumstance: A and B are people who belong to two different communities; there are two substances A and B that are superficially similar but have different micro-structures; the two communities use A and B for the same sorts of things; and when any member of community A refers to A he or she has the same internal mental state that a member of B has when he or she refers to B . Now, we are asked whether A and B mean the same thing by their respective words for A and B—whatever that word or those words happen to be.
If a more realistic, concrete case helps, consider jade, which Putnam briefly talks about in his 1975 paper. (What Putnam says about jade strikes me as right but also strikes me as exactly the opposite of what he should have said on the basis of his own theory!) Jade is not a single kind of stuff. Rather, there are two different minerals, jadeite and nephrite, that go by the name “jade” because they have a bunch of very similar macroscopic properties, even though they have very different micro-structures. We could imagine two communities—one that has only ever seen jadeite and one that has only ever seen nephrite. Now, suppose that Billy asks for some jadeite at his local market, and Suzy asks for some nephrite at her local market. And suppose that their concepts are identical. They are both thinking of a hard, waxy, precious stone with a greenish-white color. Do their words have the same meaning (for them)?
According to Putnam’s theory, the answer should be NO. If Billy were to discover a piece of nephrite and say that it was jadeite, he would be wrong. Why? In part because the micro-structure of the stuff that his community baptized as “jadeite” is nothing like the micro-structure of nephrite.
Now, I will not deny that for some thought experiments, the hypothetical may be usefully resisted. The Chinese Room is one such thought experiment. And, I agree that one could refute a thought experiment by disputing its premisses. For example, by showing that if the premisses are as they must be, the conclusion or lesson of the thought experiment changes. But when that works, it is because the premisses that are being disputed make a difference for the conclusion reached. In the case of Putnam’s H2O / XYZ thought experiment, the physical facts just don’t matter.