In Putnam’s paper Meaning and Reference, his infamous ‘Twin Earth’ example is designed to refute the idea that “meaning is in the head”. In his Twin Earth example, Putnam describes ‘Twin Earth’ as a place that is essentially a duplicate of earth. Everything on this Twin Earth is the same, except for the molecular structure of its water. Instead of its water having a chemical structure that consists of H20, its chemical structure is XYZ. Although it does contain the same superficial characteristics of water, Putnam theorizes that this XYZ Water’ is not the same as the ater here on earth.
Thus, Putnam draws his first conclusion. He concludes that the extension of water on earth differs from that of its counterpart. The next part of Putnam’s Twin Earth argument claims that if our standard of psychological difference is what is in the head, there can be no psychological differences between the speakers of both worlds. If this is true, we must then redefine the traditional concepts of meaning that have been defined by other philosophers. As of now, there are two unchallenged assumptions of the theory of meaning.
The first being, ” knowing the meaning of a term is Just a matter of being in a psychological state”and the second being, “the meaning of a term determines its extension”. Putman then takes his ‘Twin Earth’ example a step further to show that in both worlds, people are in the same psychological state. He brings in Oscar from Earth and Oscar from Twin Earth, both of which have the same intention of getting water. He then takes us back to a time where no one knows what the molecular structure of water is. But even though no one knows that water is H20, when Oscar from earth hinks of water it is H20 regardless if he knows it or not.
The same goes for Oscar from twin earth. When he thinks of water, it is still XYZ regardless if he knows it or not. Therefore, both Oscars can have the same intention, but different extensions. Thus disproving that the theory that the meaning of a term determines its extension. If this is the case, Putnam believes that you must drop one of theories of meaning he is critiquing. Either knowing the meaning of a term is Just a matter of being in a psychological state or the meaning of a term determines its extension. Either way, ou can’t have both.
Overall, Putnam believes that we should give up the claim that meanings are in the head. We begin to see Putnam’s indexicals come into play when he gives his two theories of Water. ‘ His first theory of water states that the meaning of water is universal, but its chemical makeup is determined by what world it resides in. Essentially, in both worlds Water’ means the same thing, but the word Water’ denotes H20 on earth and XYZ on Twin Earth. In his second theory of water, Putnam claims that water is universal in denotation, but has a different meaning in each world.
Therefore, if water on earth is H20, then it is H20 in all possible worlds that one can conceive of. Thus, since water on Twin Earth denotes XYZ, then it is not water. This XYZ substance last theory of water that Putnam brings in indexicals. Putnam believes that this theory reveals that terms are intrinsically indexical and therefore rigid. Like Kripke, Putnam believes in rigid designators. Putnam believes that a term should exist in the same way in every conceivable world one can think of. He holds this idea true for water.
Since the word Water’ means H20 on earth, it rigidly esignates H20 in every possible world. Therefore, Twin Earths XYZ Water’ does not have the same meaning that Earths H20 Water’ has. Putnam then summarizes his theory by saying, “an entity x, in an arbitrary possible world, is water if and only if it bears the relation same (construed a cross-world relation) to the stuff we call “water” in the actual world”(Putnam, pg. 101). According to Putnam, the rigidity of Water’ is supposed to be a consequence of its indexicality. He claims that the term Water’ is rigid because of its ostensive definition.
In order to do this, one must point at any liquid of their choosing and declare it as water. According to Putnam, this gives water meaning because by pointing at a liquid and claiming it to be the extension of the word, you are revealing the very nature of the stuff. Therefore, the actual nature of the sample (regardless of what anyone else believes it to be), gives rise to the meaning of the word. All in all, when assessing Putnam’s theory, there are several implications that arise from it. For one, we find that words are more indexical then we had previously assumed.
In his theory, meanings become more social and go far beyond the capacity of individuals. Essentially, the meaning of a term depends on what another person or expert has to say about it. Putnam also believes that the actual makeup of the things we talk about enters into the meaning of the terms we use. Overall, the underlying connection between the term and the establishing of what it is fixes the reference. For Frege, the idea that an intention is distinct from extension goes completely against his view. Frege believes that intentions are senses and those senses are bstract objects.
Thus, both have a completely different opinion on what an intention is. When Putnam goes deeper into his argument and brings up the two theories he is challenging, he is basically challenging Frege’s theories on meaning and reference. Unlike Putnam, Frege believes that even if meanings are abstract objects, you understand their meaning by being in a certain psychological state. Frege also believes that sense determines the reference, which is the second theory Putnam is trying to refute. Frege defends this view with his famous evening star example.
It is in his example he claims that the meaning of a term provides necessary and sufficient conditions for membership in the extension ofthe term. Ultimately, Putnam goes on to argue against these claims with his “Twin Earth” example. As for my own critique of Putnam, I would partially side with Frege. I will agree that the same intention does not determine its extension, but I do think terms are psychological. Knowing the meaning of term is Just a product of being in a certain psychological state because reality doesn’t actually exist. Meaning can’t give definition to something if meaning itself is a human construct.
Therefore, the mental/ psychological state has to come virtual creation from whatever we call our mind. My second critique has to do with the science behind Putnam’s Twin Earth. Overall, it is hard to conceive of a world Just like ours without there being H20. Without H20, it is literally impossible to have an identical world or ‘Twin Earth’. Even the slightest change in H20 produces dramatic events in its structure. Therefore, ‘Twin Earth’ would not be like earth. I understand Putnam’s argument and what he was trying to get at with his example, but this concept was very distracting for me.