Scientists only abandon a paradigm when a better one is available

what scientists never do when confronted by even severe and prolonged anomalies. Though they may begin to lose faith and then to consider alternatives, they do not renounce the paradigm that has led them into crisis.

They do not, that is, treat anomalies as counterinstances, though in the vocabulary of philosophy of science that is what they are.
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the act of judgment that leads scientists to reject a previously accepted theory is always based upon more than a comparison of that theory with the world.

The decision to reject one paradigm is always simultaneously the decision to accept another, and the judgment leading to that decision involves the comparison of both paradigms with nature and with each other.