The trouble of philosophy of science is that the thinker is trying to explain on what principles the scientist should think, but is himself bound by certain principles on how he should think. So, for example, when Popper says that all scientific theories must be in principle falsifiable, he is in fact making a non-falsifiable statement, and so it is my his own definition pseudo-scientific. Of course, he would say that he is not claiming his philosophy to be scientific as such, but defining whether other theories are. But then one must ask, why listen to Popper's ideas? Moreover, can or should one apply this to historical theories? It is all very well applying it to contemporary (for Popper) pseudoscience like Marxism and Freudianism, but what about geocentrism, phlogistons and the four elements? One can certainly make an argument for and against any of these being falsifiable, but that would be beside the point, because these theories, when they were overturned, were not discussed in such terms, but in the terms common to scholarly argument at the time.
To analyse this in Kuhnian terms, it turns out that philosophy of science, as well as science itself, runs in dominant paradigms for a while before being replaced by new paradigms.
It is to this end that all philosophers of science need to be deeply acquainted with the history of science, and especially the history of the philosophy of science. (What a wonderfully interdisciplinary area of research!) The only book I have managed to find on the subject is this one, which is surely the definitive treatment, and Dr Losee rises to the challenge admirably with a detailed and polymathic overview of a wide range of thinkers and scientists across multiple millennia. One cannot help but admire his understanding of defunct thought patterns; each section deserves to be read multiple times in order to grasp the content. It is only a pity that more philosophers will not engage with history at such a high level.