Ostensive Definition and the Problem of Pointing

Core Idea

Ostensive definition—pointing at an object and saying its name—seems the most primitive way to teach and learn language. Yet Wittgenstein showed that pointing alone cannot fix meaning: the same gesture could mean different things depending on context (the shape? the color? the material?). Ostensive definition works only within a language-game where participants already share understanding of what is being defined. Pointing is not a foundation for language but depends on language.

Explainer

From your study of Wittgenstein's language games, you already know that meaning is not a fixed property words have in isolation — it emerges from the practices, rules, and shared forms of life within which language is embedded. Ostensive definition is the most ancient and intuitive theory of how meaning gets established: you point at an object and say a word, and the learner comes to associate the word with the thing. It seems like the bedrock of language acquisition. Wittgenstein's devastating insight is that this apparent foundation is itself already dependent on language.

Here is the problem. When you point at a red apple and say "apple," what exactly does your gesture indicate? You might mean: the object in front of you, the color of it, the shape of it, the species of plant it came from, the surface texture, the category of fruit, or any number of other features. The physical act of pointing — the gesture itself — does not determine which feature is being named. The same is true of any ostensive act. If I point at your dog and say "dog," I might be pointing at the animal, at the color of its fur, at the concept of domesticity, at the breed, or at a spatial location. The pointed-at object has indefinitely many properties, and the finger-pointing gesture selects none of them on its own.

What resolves the ambiguity? The answer is that the learner must already have a grasp of the relevant category — they must know in advance that words can name *objects* as opposed to colors, or colors as opposed to shapes. They must understand the *kind* of definition being given. But this prior understanding is itself a piece of linguistic competence. As Wittgenstein puts it: "An ostensive definition can be variously interpreted in every case." You cannot establish even the first word without a prior framework that tells you what the pointing gesture is doing. The definition presupposes the very competence it is supposed to produce.

This has profound implications for theories of language acquisition and for philosophical accounts of reference. The empiricist picture — that we build language from scratch by labeling bare sensory experience — is undermined. Children do not learn language by passively receiving labels; they are already participating in structured social practices (joint attention, turn-taking, shared activities) that establish what words are about before any explicit definition is given. Shared forms of life — Wittgenstein's phrase — do the foundational work that pure ostension cannot do. Language is caught, not taught through pointing alone.

The practical upshot is that there is no such thing as a private ostensive definition — an act of naming one's own inner experience that grounds meaning purely in the individual's mental act of pointing inward. Wittgenstein uses this argument against the possibility of a private language: a language whose terms refer to one's own private sensations and could in principle only be understood by oneself. Such a language is impossible because there would be no way to establish that any repeated use of a word correctly tracks the same type of experience — correctness requires a standard, and a standard requires a community. Ostensive definition, it turns out, is a social achievement from the very first gesture.