  The Duhemian thesis usually makes its appearance in the context of Duhem’s critique of the inductive method (or what he calls the Newtonian method), which rejects any hypothesis about imperceptible bodies and hidden movements and admits only general laws known by induction from observation. Duhem accuses this method of being unmanageable; he asserts that a science can only follow the Newtonian method when its means of knowing are those of common sense: “When science no longer observes facts directly but substitutes for them measurements, given by instruments, of magnitudes that mathematical theory alone defines, induction can no longer be practiced in the manner that the Newtonian method requires,” (1917, 153; [EHPS, 234]). He clearly indicates that some sciences can use the Newtonian method, derive their principles by induction from observation and disconfirm them as tests warrant. What Duhem thinks is wrong with inductivism is that it cannot be used by all sciences. For Duhem the non-falsifiability thesis is a consequence of the non-separability thesis, and the non-separability thesis is an empirical thesis depending upon factors that do not govern all sciences. This is supported as well by Duhem’s assertions, in La théorie physique, that he is imposing narrow limits on his inquiry, and is restricting his generalizations to physics; when he first announces the non-separability thesis, he announces it as a principle about what physicists do, whose consequences will be developed in the remainder of the book.