The power of science doesn't come from scientists being smarter than everyone else — it comes from a method designed to catch their mistakes. The core move is falsifiability: a scientific claim must make predictions that could, in principle, be shown false by observation. 'All swans are white' is scientific because a single black swan disproves it; 'invisible undetectable fairies cause gravity' is not, because nothing could ever refute it.
This inverts normal human reasoning. People naturally seek evidence that confirms what they already believe (confirmation bias). Science deliberately does the opposite: it tries to break its own theories through controlled experiments, peer review, and replication. A theory earns trust not by being proven true — you can never prove a universal claim absolutely — but by surviving repeated genuine attempts to prove it false. That's why 'it's just a theory' misunderstands what a scientific theory is: it's an explanation that has withstood serious efforts to destroy it.