Paradigm Shift

Definition

A scientific revolution is the wholesale or partial replacement of one paradigm by an incompatible successor — not an extension of the old framework but a break from it. Kuhn insists the break is real even when the new theory's equations can be made to "reduce" to the old ones: the derivation that recovers Newton's laws from relativity changes what every symbol in them means, so accepting the new theory means you cannot also hold what practitioners of the old one meant by their own terms.

In the Book

Kuhn develops the idea through an extended political analogy: revolutions begin when existing institutions are seen to have stopped solving the problems they created, proceed through a period when the community splits between rival frameworks, and end by means outside the old framework's own rules — persuasion and demonstration, not appeal to a shared procedure, because the rules themselves are what's in dispute. He uses this to dismantle the "special case" reading of scientific progress: Einsteinian mass, space, and time are conceptually different objects from their Newtonian namesakes, not refinements of them.

Why It Matters

The concept explains why major transitions — in science, organizations, or belief systems — cannot be resolved by simply presenting better evidence to the old regime: when the disagreement is about which framework supplies the standards of evidence, argument becomes circular on both sides. It reframes discontinuous change as a distinct kind of event, not a bigger version of ordinary revision, with its own dynamics of persuasion, defection, and irreducible framework conflict. (Note: paradigm-shift and other paradigm-rooted slugs in this book are claimed by Kuhn as the originating source, superseding the provisional reservation of paradigms elsewhere in the atlas.)