allisbe noted

“All we can do is to search for the falsity content of our best theory. We do so by trying to refute our theory; that is, by trying to test it severely in the light of all our objective knowledge and all our ingenuity. It is, of course, always possible that the theory may be false even if it passes all these tests; that is allowed for by our search for verisimilitude. But if it passes all these tests then we may have good reason to conjecture that our theory, which (we know) has a greater truth content than its predecessor, may have no greater falsity content. And if we fail to refute the new theory, especially in fields in which its predecessor has been refuted, then we can claim this as one of the objective reasons for the conjecture that the new theory is a better approximation to truth than the old theory.”

Karl Popper