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Prescriptive versus Descriptive Rules

When debating terminology, I have several times run across the issue of prescriptive versus descriptive rules. A prescriptive rule states how people should use a word; a descriptive rule states how people do use a word.

For example, many people pronounce "nuclear" as "new-cue-ler". Webster's has even accepted this oddity as one among several pronunciations. But does Webster's inclusion of the pronunciation mean that it is "correct" to pronounce the word that way? I don't think so. The inclusion of the pronunciation is descriptive; they included the pronunciation because it describes how a significant portion of the English-speaking population pronounces the word. They are not endorsing the pronunciation.

Interestingly, the same sorts of issues arise in the rules of games. I have debated rules of poker, for example, with people who insist the rule they follow is "correct" because everyone seems to play that way. But when I look up the rules in an authoritative source, such as Hoyle's Rules of Games, I sometimes find that the "official" rules differ from the common way in which people play.

I favor acting according to prescriptive rules rather than descriptive rules. Discrepancies between prescriptive and descriptive rules typically arise from ignorance - a larger and larger number of people who aren't familiar with a traditional rule begin to behave differently until few people even know what the original rule was. I want my rules to be based on full knowledge of both common usage and history, which sometimes means dismissing common usage as based on ignorance.


Prescriptive rules must be justified. They are normative. X should be done this way because Y. Descriptive rules do not require justification because they are empirically verifiable. A descriptive statement is either true or false. A truly prescriptive statement cannot be true or false.
Roger L. Cauvin said…
The fact that a descriptive rule is one that people actually use doesn't make it "true" or "false". We might define the "truth" of a rule as depending on its popularity. In that case, descriptive rules would be empirically verifiable (subject to the possibility of surveying use of them). However, no rules are true or false in isolation.
I'm not sure is prescription NEEDS to be justified. It certainly is not always justified in English!

Why not justify the action of prescribing rules by the need for a group of people from varying backgrounds (each with descriptive rules of their own) to efficiently converse with one another.

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