Throughout the history of analytic philosophy, the problem of meaning has been and remains one of its central themes. Semantic studies of recent decades have underscored the unrelenting interest of philosophers in this issue. The criticism of the traditional theory of meaning is one of the most critical developments in analytic philosophy in recent times. This criticism was initiated by the creators of the so-called “new theory of reference,” among whom is the prominent American philosopher and logician Hilary Putnam, the founder of “Twin Earth” thought-experiment.
Before substantiating Putnam’s theory, it is necessary to briefly define what is meant by the traditional theory of meaning. McGinn (1977) states that the sense of the linguistic expression is a two-component entity. It denotes some object with a denotation or extension and expresses some meaning with intension. Secondly, the meaning of a linguistic expression is understood as a set of descriptions. A general term is a description of properties or characteristics that are common to all objects included in the extension of this term. Thirdly, the intension of a term defines its extension because something is included in the extension of the term only if it has the characteristics included in the term’s intension. The concept of analytic truth is closely related to intension. A sentence is considered analytical if its truth is established based on the intensions of the terms included in it. For example, if P is a property included in the intension T, then the statement “All T is P” is analytically true. Thus, in a generalized form, the traditional theory contains the above provisions.
Hilary Putnam offers arguments against the traditional approach to show the inadequacy of the traditional understanding of meaning in general. Putnam (1975) argues that the words meaning, understood as an intension, determines its extension in the sense that the intension forms a necessary condition for the object to enter the extension. According to Putnam (1975), there are two simple aspects behind this dependence of extension on intension. Firstly, from the identity of the intensions of two words, the sameness of their extensions follows. Secondly, words that coincide in extension can have different intensions. For example, “a living being with kidneys” and “a living being with a heart” distinguish the same class of objects.
Of particular importance in Putnam’s activities is his “Twin Earth” thought-experiment. Putnam (1975) believes that the mental state cannot determine the extension of a term. To prove this, Putnam offered a little science fiction story about Twin Earth and water. Somewhere far in space, there is a planet “Twin Earth,” which is similar to the Earth in everything. The only difference is that the oceans, seas, and rivers on this planet are filled with liquid, which at standard temperature and normal pressure is indistinguishable from water, but not described by the formula H2O. The chemical structure of this liquid is expressed by a very complex formula, which for brevity sake can be written as XYZ. If at some moment contact is established between the two planets and a difference in the meaning of the word “water” is found, then this difference is easily explained. It is because different extensions correspond to varying definitions of the word “water.” On Earth, the extension of the word “water” is a set of compounds consisting of H2O molecules. In turn, on Twin Earth, the extension of the word “water” is a set of compounds comprised of XYZ molecules.
It seems that neither on Earth nor Twin Earth is known the chemical formula of water, which took place, for example, in 1750. Therefore, if choosing two people, one of whom lived in 1750 on Earth and the other on Twin Earth, it should be recognized that both were in the same mental state when thinking about water. Nevertheless, according to Putnam (1975), the extension of the word “water” in 1750 was the same on Earth as in 1950, that is H2O. In turn, the extension of the word “water” on Twin Earth in 1750 and 1950 was substance XYZ. Thus, this difference in the reference of the word “water” on Earth and Twin Earth does not correspond to any difference in the mental state of the inhabitants of either planet. It could serve as an explanation for the difference in extensions, which means that the assumptions underlying traditional theory cannot be valid. Accordingly, Putnam concludes that the concept does not determine the extension of natural species terms that the speaker has in mind.
Therefore, Putnam’s thought experiment was to refute the relativistic interpretation of reference. The philosopher wanted to prove that the concepts of true scientific theories refer not to mental representations but the real world. As a result of this research, Putnam came to two effects: the formulation of the theory of natural classes and the sociolinguistic hypothesis – the idea of the division of linguistic labor. McCulloch (1995) notes that the sociolinguistic hypothesis determined one of the main aspects of interpreting the concept of truth in the future idea of pragmatic realism. According to this hypothesis, from the fact that people can make mistakes and incorrectly correlate concepts with objects of reality, a relativistic interpretation of reference and truth does not follow. Since scientists know the correct use of notions, the whole language acquires referential definiteness. Suppose any person or any historical epoch does not possess scientific knowledge and formulates false sentences. In that case, it does not follow that language is not capable of referencing to reality, that subjective states of consciousness are always denotations of concepts, that it is impossible to create true scientific theories.
Putnam’s arguments have convinced many philosophers of the inadequacy of descriptive semantics. However, many considerations cast doubt on the unconditional nature of such a conclusion. According to Fodor (1987), there is a possibility of erroneous attribution of this or that object to some biological species, as was the case with the XYZ substance in the thought experiment with Twin Earth. The liquid on Twin Earth, which coincides in its external phenomenological properties with water, is not water since it does not have a similar nature with the liquid that is called water on Earth.
It must be admitted that Putnam’s preferred theory contributed to the formation of a more adequate and deep understanding of how language functions and how it interacts with the outside world. Critics of the traditional theory of meaning have exposed real problems with the descriptive interpretation of meaning. However, in condemning the traditional theory of meaning, one should not forget the issues that Putnam turned to descriptive semantics to solve. In essence, the new theory of reference contains a solution for the simplest case, namely, for the regular use of names. Moreover, Putnam’s constructive ideas involve relatively strong assumptions, the truth of which is not at all obvious. Therefore, Putnam’s preferred theory cannot overcome the “explanatory irrelevance” objection.
Thus, Putnam’s “Twin Earth” thought-experiment serves as an illustration of his argument in favor of semantic externalism. The philosopher believes that the meanings of words are not purely psychological. Despite the conviction of many philosophers in the reliability of this experiment, many still sit in judgment of this idea because of its unreliability. Nevertheless, Putnam made significant contributions to philosophy, criticizing the traditional theory of meaning. The debate with the traditional theory of meaning is not over yet.
References
Fodor, J.A. (1987). Individualism and supervenience. In J.A. Fodor (Ed.), Psychosemantics: The problem of meaning in the philosophy of mind (pp. 34–58). The MIT Press.
McCulloch, G. (1995). The mind and its world. Routledge.
McGinn, C. (1977). Charity, interpretation, and belief. The Journal of Philosophy, 74(9), 521-535. Web.
Putnam, H. (1975). The meaning of “Meaning.” In H. Putnam (Ed.), Mind, language and reality (pp. 215–247). Cambridge University Press.