Every scientific theory has predictive power, and something else that we don’t normally think about: a range of validity. In other words, we’re going to do experiments, make observations, and otherwise poke-and-prod the predictions of this theory. Ideally for a scientific theory, the range of validity will be as large as your experiments/observations permit, and the any discrepancies will be solely due to experimental/observational errors. This was why Newtonian gravity was the most successful theory of all time; it stood, unchallenged, for the better part of three centuries.
In this sense, we’re all scientists; every time we encounter something in the natural world that isn’t explained by our current understanding of it, we revise our explanations so that they can explain both the old phenomena that our previous explanations took care of, but also explain the new phenomena that the archaic explanations are insufficient for.