Final version of that Phil paper. I think it’s a lot cleaner than the last version, so I’m satisfied with how it turned out.
Intuitions about Intensions
In “Meaning and Reference,” Hilary Putnam challenges the theory that meaning is just a set of properties that picks out certain objects. He believes that psychological states don’t exactly determine the referenced objects. To show this, he first separates this theory, known as the verifiability theory of meaning, into two parts: 1) psychological states determine the meanings, or intensions, of words, and 2) the intensions determine the referenced objects, or extensions, and then proves that these parts aren’t jointly satisfiable. Although he maintains that intensions determine extensions, Putnam only gives a short argument in a footnote for why he believes this. I will first analyze what Putnam does say on whether intensions determine extensions, then give a counter-example to show why his argument isn’t compelling.
First, consider how Putnam uses intensions in his argument to show that psychological states don’t determine extension. Putnam doesn’t explicitly define intension, only saying that knowing a word’s intension is to understand the word. I will interpret Putnam to denote meaning when he says intension, and reference when he says extension. Putnam first assumes that intensions determine extensions in the Twin Earth example. As mentioned, he separates the belief that psychological state determines extension into two parts, with intension as the bridge. To prove this theory wrong, he must show that exactly one part is true, and exactly one part is false. If both are true, then the theory holds, which is not what he wants. If both are false, then the decomposition is meaningless because we haven’t established any causation from psychological states to extensions through intensions. He attacks the claim that psychological states determine intensions with the H2O-XYZ thought experiment and socio-linguistic division of labor. Since exactly one must be false and Putnam shows that “psychological states determine intensions” is false, then he must believe that “intensions determine extensions” is true.
Later in his discussion of indexicality, Putnam gives more evidence that he believes intensions determine extensions. He points out that natural-kind words have an implicit indexicality. Put differently, words grouped by natural, not artificial qualities also depend on the frame of reference of the speaker. For example, when we say “water,” we’re referring to everything that appears to be watery in our local environment. Depending on the universe, that “water” might be H2O or XYZ, so Putnam claims that “words have intensions” and “intensions determine extensions” cannot both be true. If they are both true, all instances of the word “water” should refer to H2O, regardless of the universe. To avoid this conflict, one must deny one of the two claims. Notably, Putnam rejects that words have intensions and says, “as we have chosen to do, that difference in extension is ipso facto a difference in meaning for natural-kind words,” to maintain his belief that intensions determine extensions (710).
Given how much the essay depends on it, Putnam surprisingly only presents a footnote for why he believes intensions determine extensions. In it, he appeals to our intuition about how words work with the following argument by contradiction. Assume intensions don’t determine extensions. Thus, two words could possibly have the same intension but different extensions. When one person on our Earth says “water” (referring to H2O) and one person on Twin Earth says “water” (referring to XYZ), they have the same meaning. We can imagine that on Twin Earth, language might have developed slightly differently, such that “water” is pronounced “quaxel.” The two words, by assumption, still have the same intension even though they are pronounced differently and pick out different objects. This intuitively is a contradiction because they seem to have different meanings, though the intensions are the same. Therefore, our assumption that intension doesn’t determine extension is false, so intensions determine extensions.
Although I share this intuition, I remain unconvinced by this argument because it takes advantage of our pre-conceived notions about water from the Twin Earth argument. Instead, I will show that Putnam’s argument isn’t universally valid. To see this, consider how Putnam believes we arrive at our psychological states and intensions. Putnam distinguishes between the operational definition and actual definition for an object. The operational definition is a standard for how we understand the nature of an object without actually determining its essential qualities. For example, an operational test for water would be a series of tests that could yield superficial properties though not guarantee certainty about the microstructure of something that might be water.
A drawback to this interpretation is that he bases the difference on an empirically determined definition for the microstructure of water. He says, “Once we have discovered that water (in the actual world) is H2O, nothing counts as a possible world in which water isn’t H2O” (710). Unfortunately, even water’s microstructure, which is Putnam’s actual definition, is based upon possibly faulty experiments, and history has shown that we will likely discover a deeper scientific quality that will allow us to make finer distinctions in the future. In 1750, one might argue that all liquids with a certain taste are water, and its transparency under a microscope was the true structure and actual definition of water. And in another 100 years, we may determine that some other characteristic could change our definition of water again. Imagine that we discover H2O can exist in non-water states as rocks on a distant planet. If we don’t accept that H2O rocks are water, then our definition is wrong. If we do accept that H2O rocks are water, then the extension of water doesn’t quite match up with what we typically intend when we say “water.” This doesn’t show that intensions don’t determine extensions, but I will exploit this counter-intuitive notion later in my argument.
With that, let’s revisit Putnam’s original argument. We can break down the difference between our water and Twin Earth water, “quaxel,” that makes Putnam’s answer so intuitive. By assumption, the intensions agree. The extensions are different because we know that one is H2O and the other is XYZ. And the pronunciation is different. Intuitively, “water” and “quaxel” can’t mean the same thing, which is the contradictory result.
So consider a different example where we again assume that intensions don’t determine extensions. We know the actual definition of oxygen based on its microstructure. We know it has 8 protons in its microstructure, commonly binds in pairs to form oxygen molecules, and is necessary for breathing. Now on Twin Earth, they also have oxygen. If we were to send our scientists there, they would agree that their air also contains oxygen. Thus, “oxygen” on both planets seems to have the same psychological state, intension, and extension. We can extend this slightly: on Twin Earth, their English sounds different, so their “yorpit” is our “oxygen.” The intension and extension are the same, and the pronunciation difference isn’t important. This result should be intuitive and unsurprising.
Now, remember the difficulty above regarding rock water. Imagine that time travelers from the future come to visit us today, and in their time, they have discovered sub-magnetic fields to make finer distinctions between elements. They discover that there are actually two types of oxygen. In Earth oxygen, a sub-magnetic field appears within its electrons but doesn’t in Twin Earth oxygen. In fact, these time travelers laugh that we call these two substances both oxygen because it’s obvious to them that they only share superficial qualities like their microstructure. To reiterate, though, both types of oxygen behave in exactly the same ways: we can breathe and fuel fire with both of them. Only because the time travelers have discovered faster-than-light methods of transportation did they notice the difference.
With this new information example, we must accept the scientific truth from the time travelers. Because of this new distinction, we now have the same breakdown as between “water” and “quaxel.” They have the same intension, but different extensions and pronunciation. In this case, it isn’t obvious that “oxygen” and “yorpit” have different meanings. Because of my social and scientific context, I don’t care about sub-magnetic fields; that has nothing to do with my meaning when I say “oxygen.” And even though “yorpit” and “oxygen” are different words, and the time traveler asserts to me that these two are fundamentally different, I still don’t believe my meaning has changed. If we analyze the difference with the “water” and “quaxel” example, we see that the controversy doesn’t come the belief that intensions don’t determine extensions; that’s consistently assumed in both cases. It’s a different pre-supposed intuition that creates different conclusions. Instead of showing that “intensions determine extensions” is necessary, these examples only prove that our intuitions about words affect its meaning.
This thought experiment doesn’t explicitly prove that intension doesn’t determine extension. Depending on how we define intension and meaning, I might still believe that intensions determine extensions. However, I don’t believe that Putnam’s appeal to our intuition is necessarily strong enough to prove this because of the limited perspective of our intuitions.
Putnam, Hilary. “Meaning and Reference.” The Journal of Philosophy, Vol. 70, No. 19, Seventieth Annual Meeting of the American Philosophical Association Eastern Division (Nov. 8, 1973), pp. 699-711. http://www.jstor.org/stable/2025079