 (5) Kuhn claimed that Popper and others had missed the existence of key structures in the history of science—the longer-term approaches that he called paradigms and hence both normal and truly revolutionary science. There are different historical scales in play: individual theories, paradigms, and the still longer-term perspective of a succession of paradigms. So Kuhn adopted a two-tiered or double-process conception of science in which there is, first, a constitutive framework (the paradigm), held immune to revision during periods of normal science, and, second, change from one framework to another. For these frameworks are historically contingent and are eventually displaced by others. Kuhn’s two-process account sharply clashed with the one-process account of Popper (1963) and many others. Ironically, given that Kuhn was also attacking positivist positions, and given his greater sympathy for Popper, the two-process account was closer to the “positivists” Reichenbach and Carnap than to Popper (see Reisch 1991; Carnap 1950; De Langhe 2014a,b; Nickles 2013a).