Why is language vague?

Language can be defined as a normative system, bound by grammatical rules to help people communicate — yet, despite its expressive richness, ordinary language is pervasively vague. This essay argues that the best explanation of vagueness comes from a broad Wittgenstein’s approach. Wittgenstein’s later philosophy emphasises that meaning is not an inherent property of words but is determined by how those words are actually used within specific human practices, “language games”.

Language is vague because concepts themselves are vague, and concepts are vague because, within the relevant language games, speakers do not need highly precise boundaries. Precision beyond what is pragmatically required would make communication unnatural and cumbersome. Therefore, vagueness does not result from ignorance or a failure of language to correspond to the world. Instead, it arises from the purposes and behaviours of its users. Vagueness is a feature of how we use language, not a bug, to put it in the programming language terms.

To begin, I will argue that everyday concepts lack sharp boundaries because our language game does not require them; these concepts are inherently vague and can only be sharpened as much as the purposes of the language game demands. For example, ordinary speakers can easily identify paradigmatically blue objects, and they can recognise paradigmatic cases of green or purple. But there are clear edge cases, such as shades that one person might call blue while another calls greenish-blue. The language game of colour classification for everyday purposes simply does not require exact boundary conditions. In practice, blue functions well because its limits are flexible; it allows speakers to communicate efficiently without the cognitive burden of specifying precise wavelength intervals every time they refer to the colour of the sky or a shirt.

One could argue against this with the assertion that hard limits do exist if we do formalise these seemingly vague concepts. For example, blue can be represented as a well-defined set of hex codes and wavelengths in the electromagnetic spectrum. The vagueness then actually comes from people’s inability to identify these well-defined limits or boundaries that specify precisely the limits. So, the language is vague due to the users of the language. However, this line of argument does not eliminate vagueness. The wavelength characterisation of colour does not align with the actual meaning of colour terms in ordinary language. When someone calls the sky blue, they are not referring to a specific wavelength interval. They are participating in a socially learned practice of colour classification. This can be further evidenced in the Sorites paradox, which can be expressed by modus ponens:

P1) One grain of wheat does not make a heap. [Base case]

P2) For each positive integer k, if k grains do not make a heap, then k+1 grains do not make a heap. [Inductive step]

C) Therefore, 1 million grains of wheat do not make a heap.

One might oppose this with the argument that there is a limit on the number of grains to make a heap, claiming that language is vague, not because the concepts are vague, but instead because we do not know the precise limits of these concepts, arguing that 500,000 grains of wheat are needed to make a heap. However, one could not tell the difference between 500,000 grains and 499,999 grains; it then follows that even a single grain of wheat, as well as any number of grains, can make a heap and also not make a heap. This indicates that language is vague, not because we have not discovered the precise limits for these concepts, but instead, it is the concepts that we refer to which are vague.

Furthermore, even if such precise limits did exist for these concepts, it would be laborious to communicate with such a level of precision, to count all 499,999 grains of wheat in order to decide that we are referring to a heap of wheat, instead the vagueness of language comes from the fact that there is no collective incentive for the language to be precise enough so as to pin down the definition of a heap of wheat down to the number of grains — this applies more broadly with colour and lots of other words. Therefore, the Sorites paradox supports the Wittgensteinian view that vagueness is inherent in the concepts reflected by ordinary language.

Moreover, it is a combination of the practical contexts, desire for efficient communication, and desire for precise communication which indicates that the users of the language game simply don't want to count the grains of the heap, in principle they could, and thus perhaps would find what the object of the limit is (i.e. number of grains needed to make a heap). But this presupposes that there are objective, human-independent facts about language that people could, in principle, go and find. This is in stark contrast to the language-game perspective, where the meaning comes from usage by people. Objectivity is implausible if we consider that the meanings of words change over time, for instance, computer, calculator and so on. Dictionaries do not contain objective, unchanging definitions but rather track how usages change over time as culture, societies, social trends and so on change.

But some words do not change over time or depend on context nearly as much as other words, such as “zebra”. Perhaps this suggests that there is an objective fact about the meaning of certain words. But this doesn’t seem right in general. Suppose that my friend group and I wanted to start using the word ‘zebra’ to mean something else, e.g. in a card game that we played or to refer to a certain type of person. The new usage of the word creates a new, valid meaning of the word ‘zebra’ valid within the friend group, though not necessarily outside of the friend group, as they are not participants in this language-subgame. Since a new valid meaning has spawned out of thin air and did not exist before, meaning cannot be objective; it changes depending on people, time, place, and context. While this example may appear rare in academic literature, it is not the case in day-to-day interactions.

In evaluation, vagueness reflects the nature of human practices. Our concepts are shaped by the purposes for which we use them, and most of the time, everyday communication does not require hyper-precise boundaries. Imposing sharp boundaries where none are needed would obstruct communication and make ordinary discourse cumbersome. Wittgenstein’s insight that meaning is determined by use shows why vagueness is an intrinsic feature of language. Therefore, language is vague because concepts are vague, and concepts are vague because speakers do not need highly precise boundaries within the language games they participate in.