Duhem-Quine thesis that a single theory can never be tested and decisively refuted by experience is well known among philosophers of science. But Duhem himself did not argue for that thesis. His argument was restricted within physical theories.
Duhem has been interpreted as an instrumentalist or conventionalist. But he did not deny the existence of a reality behind the theory. Duhem's realism is very different from contemporary scientific realism. To understand his philosophy of science, it is important to note that he was a Pascalian and argued for intuition as well as logic. His philospophy of science is similar to that of M. Polanyi.
