March 1987
The following arguments are attempts to show that private language is impossible, as inspired by the Philosophical Investigations of Ludvig Wittgenstein.
Argument I.
1. All language in use tends to drift (change meaning), because:
- a. People apply old language in new contexts, therefore definitions change.
- b. Cultures meet and meld (change, accommodate) at their intersections.
- c. Atypicality is deliberately employed.
(Each of the above is a sufficient condition for change. The categories are not cleanly discrete.)
2. Drift in language both enhances and limits its utility.
Drift enhances the utility of language in meeting new situations.
Drift limits ability to communicate with others: contemporaries, forebears, descendants.
3. One of the devices which thwarts drift in language is to make them rule-based, establishing standards of correct and incorrect usage.
4. A rule is a social norm, norms are socially defined. No one person can establish a social norm.
5. Therefore, language cannot be based on the actions and judgments of a single individual. (There can be no private language.)
Argument II.
1. Language is a rule-based system. The rules are social norms.
2. In a rule-based system, I either abide the rule or I do not.
3. Thinking that I abide the rule and abiding the rule are not the same thing. I do make mistakes.
4. Only the testimony of others can assure me that I actually am keeping a given rule when I think I am doing so. (This is one reason why we have judges, umpires, etc.)
5. If I think I am keeping a rule, and those around me say that I am not keeping that rule, there is no infallible internal evidence to which I can turn to prove either to myself of to others that I really did keep the rule. I must look for, find, and proffer external evidence (a photograph, circumstantial evidence, the testimony of additional persons, etc.) to assure that I kept the rule.
6. The search for external evidence to prove that I kept the rule is done to prove to others that I really did what I think I did. Therefore, others are the basis for being sure I abide the rule.
7. Therefore, there is no private language (no linguistic structure wherein I make up the rules, use the rules, judge that I use the rules, and have a right to be absolutely sure that all that is done correctly).