Scientific Thinking
Theory vs Hypothesis
In everyday speech "theory" can mean a hunch, but in science a theory is the opposite of a guess. Here’s how a hypothesis differs from a scientific theory.
| Aspect | Theory | Hypothesis |
|---|---|---|
| What it is | A broad, well-tested explanation | A specific, testable prediction |
| Evidence behind it | Large body of confirmed evidence | Proposed, awaiting or undergoing testing |
| Scope | Explains many observations | Addresses one particular question |
| Role | The current best explanation of how something works | A starting point to test an idea |
| Example | The theory of evolution by natural selection | "This fertiliser will increase crop yield" |
When to use theory
Use "theory" for an explanation that has survived extensive testing and unifies many findings — like the germ theory of disease or plate tectonics.
When to use hypothesis
Use "hypothesis" for a specific, testable statement you set out to support or refute with evidence — the unit of a single experiment.
Frequently asked questions
- Is a scientific theory "just a theory"?
- No. In science, a theory is a well-substantiated explanation backed by extensive evidence — among the strongest things science offers, not a hunch. The casual sense of "theory" (a guess) is closer to what scientists call a hypothesis.
- Can a hypothesis become a theory?
- Not by simple promotion. Hypotheses that survive repeated testing become part of the evidence supporting a broader theory. A theory is not a "grown-up hypothesis" but a wider explanatory framework built from many confirmed findings.
- What makes a good hypothesis?
- It must be testable and falsifiable — it makes a specific prediction that evidence could contradict. "Plants grow taller with more light" is testable; a claim no observation could ever disprove is not a scientific hypothesis.