Word
Theory
In science, not a guess but a model that has survived hard testing: it explains what we have already seen, predicts what we have not, and can still be proven wrong
Examples
“It's just a theory” misuses the word: in science, a theory is the most tested kind of explanation we have.
A theory can be overturned by a single reliable observation it cannot accommodate.
Origin
From the Greek theōria, “contemplation, a looking at.” The casual sense means a mere speculation, the scientific sense a rigorously tested model. The two pull in opposite directions, which is the source of endless confusion about phrases like “the theory of evolution.”
How it connects
In science the word means almost the opposite of its casual use: not a guess, but a model that has survived testing.
This word appeared in A model that survives attempts to kill it, the Involves connection for August 16, 2026, which asked: What makes an idea scientific rather than just convincing?
Check yourself
In science, what is a theory?
A well-tested explanatory model that predicts and can, in principle, be disproven.. Right. A scientific theory is a tested, predictive model: never final, but hard-won and hard to displace.
What the sources establish
A scientific theory is characterized by explanatory and predictive power and by remaining open to empirical refutation.
Sources
Karl Popper (Encyclopaedia Britannica, 2024), Sections on falsifiability and the demarcation of science