Changes

In fact, Barseghyan notes that "as early as in The Logic of Scientific Discovery, Popper points out that it is the modifications of a theoretical system that should be assessed, not the system itself. Surely, the central requirement of Popper’s system – the requirement of falsifiability – is applicable to an individual theory ... yet, Popper realizes that falsifiability alone doesn’t allow distinguishing between two competing theories when both are falsifiable and, thus, he formulates additional rules of theory appraisal which are essentially comparative".[[CiteRef::Barseghyan (2015)|pp. 186]] Although Popper thus subscribes to the aforementioned ''comparativist'' view, Barseghyan believes he "inches towards ''the contextual appraisal view'' when he devises a rule that applies only to theory modifications: he prescribes that a theoretical system should be modified in such a fashion that the overall empirical content of the system is not diminished". And, continues Barseghyan, Popper "comes even closer to ''the contextual appraisal view'' in his Conjectures and Refutations, where he concedes that in any experimental situation scientists “rely if only unconsciously on… a considerable amount of background knowledge”.[[CiteRef::Popper (1963)|p. 322]]".[[CiteRef::Barseghyan (2015)|pp. 186]]While "it is nowadays common knowledge that any theory assessment presupposes some “unproblematic” background knowledge," Barseghyan emphasizes that "this background knowledge is often presented as a matter of choice or agreement, or, as Popper would have it, as a result of “methodological decisions”.[[CiteRef::Popper (1963)|pp. 151, 322–330]]. Yet, it must be clear that new generations of scientists do not choose their background knowledge, for they are in no position to start from scratch. What they deal with is the existing scientific mosaic: they take it where they find it and try only to modify it by replacing some of its elements by new elements". This final point is reflected in the ''contextual appraisal theorem''.[[CiteRef::Barseghyan (2015)|pp. 186]]  Kuhn, like Popper, gets close to the "contextualist" account.