According to the “standard interpretation” of WRPL (favored by Wright, Boghossian, McGinn, and Goldfarb), the epistemological argumentation and metaphysical conclusion of the skeptic’s ruminations in Chapter 2 can be reconciled by viewing the overtly epistemological argumentation as merely a “dramatic device” for developing a fundamentally metaphysical argument. The epistemological challenge – to defend your claim that you know that you mean addition and your claim that you are justified in answering “5” – takes place under conditions in which you are granted ideal epistemological access to all of the sorts of facts capable of constituting your meaning addition by “+.” In this chapter, I will defend the standard interpretation against a recent attack launched by Hannah Ginsborg, and I’ll argue that the standard interpretation fits the text of Chapter 2 of WRPL more smoothly than Ginsborg’s alternative proposal. I’ll also make some comments on Ginsborg’s notion of “primitive normativity.”

This chapter summarizes the results from Chapters 4-8 and speculates on a question that is posed at the start of the book: Why is it that Milgrom’s theory, in spite of its remarkable successes, has been so widely ignored by standard-model cosmologists? It is argued that the approach of standard-model cosmologists to theory corroboration is different from that of Milgromian researchers: the first behave like verificationists, the second like critical rationalists. Unlike Milgrom’s theory, the standard cosmological model has made few if any successful novel predictions, and so it is understandable that standard-model cosmologists have gravitated toward a methodology that favors verification over critical rationalism.

Scientific epistemology begins from the idea that the truth of a universal statement, such as a scientific law, can never be conclusively proved. No matter how successful a hypothesis has been in the past, it can always turn out to make incorrect predictions when applied in a new situation. Karl Popper argued that the most important experimental results are those that falsify a theory, and he proposed falsifiability as a criterion for distinguishing science from pseudoscience. Popper argued in addition that scientists should respond to falsifications in a particular way: not by ad hoc adjustments of their theories, but in a way that expands the theory’s explanatory content. Popper argued that the success of a modified theory should be judged in terms of its success at making new predictions. Popper’s view of epistemology, which is shared by many scientists and philosophers of science, is called “critical rationalism.” An epistemology that judges success purely in terms of a theory’s success at explaining known facts is called “verificationism.” Popper argued that verificationism is equivalent to a belief in induction, and that induction is a fallacy.