Does science ever prove anything for certain?

No, not in the strict sense of the word. Proof belongs to mathematics and logic. Science works with evidence. That can sound like a weakness, but it is a big part of why science keeps getting better.

People ask this for good reasons. A headline says scientists have proved something, and later another headline seems to say the opposite. A relative calls evolution “just a theory.” A video argues that since science can’t prove everything, any idea is as good as any other. These are fair things to wonder about.

Here is the core picture. In mathematics, a proof starts from agreed rules and uses logic to show that a statement must follow. In 1995, the mathematician Andrew Wiles published a proof of Fermat’s Last Theorem, a claim about whole numbers first stated in the 1600s. His proof covers every case at once, which no amount of checking examples could ever do.

Science is different, because its claims are about the real world. As a matter of logic, no pile of observations can show that a general law holds everywhere and always. In principle, one solid counterexample can show that it fails, though in practice scientists first check whether something else went wrong. So scientists talk about evidence and confidence. The U.S. National Academies put it this way: science aims for refined degrees of confidence, rather than complete certainty.

That does not make science a guess. Some ideas are backed by so much evidence that no new finding is likely to overturn them: the Earth goes around the Sun, living things are made of cells, and matter is made of atoms. Engineers use well-tested science to design airplanes, and the airplanes fly. Even these ideas stay open to refinement. That openness is part of why they can be trusted.