Science explained

Hypothesis, theory and law: the differences

In science, a hypothesis, theory and law are different kinds of statements; a theory does not simply 'graduate' into a law.

Scientific methodVocabulary

Editorial review: August 12, 2026 · Julian E. Marston

Hypothesis

A hypothesis is a testable proposed explanation or prediction for a specific question.

Theory

A scientific theory is a broad explanatory framework supported by extensive evidence and successful predictions.

Law

A scientific law describes a consistent relationship or pattern, often mathematically, without necessarily explaining why it occurs.

Why the distinction matters

Calling evolution, atomic theory or germ theory 'just a theory' uses the everyday meaning of theory rather than the scientific one.

This page explains scientific concepts for general learning. It does not replace laboratory safety procedures, professional engineering guidance, or individualized medical advice.