Meaning Change for Natural Kind Terms

Abstract

Diachronic linguistics studies and explains the ways in which langRages change over time. It studies changes in phonetic, grammatical, and semantic items, and in whatever theoretical entities linguists postulate to do ordinary synchronic linguistics. In this paper I want to consider the effects of scientific investigation on the meanings of natural kind terms. I will present a diachronic model of the way such terms undergo meaning changes. Consider some of the ways in which science has an effect on language. Scientists may discover important distinctions that are not captured by current natural language or by the technical vocabulary the scientists inherit. They may suggest new words or a new usage of old words to reflect such distinctions. On the other hand the scientists may discover that natural language has terms for classifying things that do not exist or for making distinctions that are no longer thought to be worth making. Then they may suggest dropping some words or usages. They might suggest a substitution, dropping an old usage and starting a new one at the same time. Historical accident enters into how all this happens. The scientist (or someone else) may explicitly suggest a change in the language or he may simply start using words in a new way, expecting that the change will catch on. In either case his attempt might fail; he may have an effect on nothing beyond his own ideolect. When a scientist does change the language, he may add clarity or confusion. The diachronic model I suggest for natural kind terms should be helpful for finding and systematizing whatever regularities are available among these changes. The model I pro-