The assertion that language is inherently social and relies on public criteria marks a pivotal shift from internalist models of mind to a normative, practice-based understanding of meaning. This perspective, often associated with the **Private Language Argument**, posits that for a sign to have meaning, there must be a distinction between *following a rule* and *merely believing* one is following a rule.
## The Impossibility of Private Verification
A central argument for public criteria is the failure of private ostensive definition. If an individual attempts to define a sensation (e.g., a specific pain) by naming it "S" in a private diary without any external reference, they lack a standard of correctness. In a purely private context, there is no way to verify if "S" is being applied consistently over time.
As there is no independent check, "whatever is going to seem right to me is right," which, as Wittgenstein observes, means we cannot even talk about "right" here. For a rule to function, there must be a possibility of being wrong, which requires a standard external to the individual’s immediate impression.
## The Normativity of Social Practice
Meaning is not a mental state but a **normative practice**. To understand a word is to know how to use it within a social context, a concept described as a **language-game**. These games are governed by shared rules that are maintained through community correction and training.
- **Public Criteria:** We use external behaviors or circumstances to ground the use of mental terms. For example, the word "pain" is not learned by looking inward, but through the public manifestations of pain (crying, flinching) and the social responses to them.
- **Intersubjectivity:** Language requires a shared framework where participants can converge on the application of terms. Without this intersubjective agreement, communication would collapse into a series of disconnected, idiosyncratic signals.
## Forms of Life as Semantic Anchors
The stability of language rests upon **forms of life** (*Lebensformen*)—the shared human activities, biological needs, and cultural practices that provide the background for communication.
1. **Consistency:** Language works because humans generally agree in their perceptions and reactions (e.g., agreeing on what constitutes "red" or "up").
2. **Praxis:** Meaning is anchored in what we *do* together. The "correct" application of a word is judged by its success within a collective activity, such as building, mourning, or calculating.
By framing language as a social institution, we move away from the "spectator" theory of knowledge. We recognize that linguistic competence is a skill acquired through immersion in a community, reinforcing the idea that a "private language" is a contradiction in terms. Meaning is a shared achievement, not a solitary possession.