Incommensurability

Incommensurability is the thesis that successive scientific paradigms can lack a common measure, so that they cannot be fully compared or intertranslated.

Definition

Incommensurability is the claim that the concepts, problems, or standards of rival scientific theories or paradigms can fail to share a common measure, so that the theories cannot be straightforwardly translated into one another or compared by a neutral standard.

Scope

This topic covers the meaning, methodological, and observational forms of incommensurability advanced by Kuhn and Feyerabend, Kuhn's later localization of it to taxonomic vocabulary, and the charges that incommensurability entails relativism or self-refutation.

Core questions

• What kinds of incommensurability are there — semantic, methodological, perceptual?
• Does incommensurability imply that paradigms are incomparable?
• Is the thesis self-refuting if it can be stated and understood?
• Can incommensurable theories still be rationally compared?

Key concepts

• meaning variance
• untranslatability
• taxonomic incommensurability
• no-overlap principle
• local versus global incommensurability

Key theories

Meaning incommensurability

Kuhn and Feyerabend argue that key terms change meaning across paradigms, so statements of one cannot be exactly rendered in the other.

Taxonomic (local) incommensurability

Kuhn later localized incommensurability to clusters of interdefined kind terms whose taxonomies cannot be mapped onto one another without violating a no-overlap principle.

History

Kuhn and Feyerabend independently introduced incommensurability in 1962. In response to charges of relativism and the objection from Davidson that an untranslatable scheme is unintelligible, Kuhn refined the thesis in later essays (collected in 2000) into a local, taxonomic doctrine compatible with bilingual understanding.

Debates

Does incommensurability entail relativism?

Critics argue that if paradigms cannot be compared, theory choice becomes arbitrary, while Kuhn replies that incommensurability is local and that bilingual scientists can learn and compare both taxonomies.

Key figures

• Thomas Kuhn
• Paul Feyerabend

Seminal works

• kuhn1962
• feyerabend1962
• kuhn2000

Frequently asked questions

Does incommensurable mean incomparable?

Not in Kuhn's considered view. Incommensurability literally means lacking a common measure, but Kuhn held that incommensurable theories can still be compared in many respects; what fails is a complete, lossless translation between their taxonomic vocabularies.