All scientific theories and laws are provisional - and thus remain as hypotheses. They become 'corroborated' by the usefulness the scientific communities who use them find them to possess. A theory or law, which should allow the possibility of being falsified, however true it seems, and however many times it appears to have resisted falsification, is still only awaiting the evidence which will falsify it conclusively. Some scientiific theories or laws are found to be so useful that they are affectionately retained as 'rules of thumb' despite having been falsified. The 'problem of induction' demonstrates the assymetry between verification and falsification. No amount of verifying instances which support a theory will verify it ultimately. However, a single clear and disconfirming instance will falsify it for all time.

Cf : David Hume, Emmanuel Kant, Karl Popper, and even Sir Alfred Ayer.

I am in so way supporting the position of Christine O'Donnell in all this. Scientists cling somewhat possessively to their theories and laws. They are human after all. The rules of logic and epistemology appear to be less accommodating.