Sanford Goldberg’s account of epistemic coverage constitutes a special case of Douglas Walton’s view that epistemic closure arises from dialectical argument. Walton’s pragmatic version of epistemic closure depends on dialectical norms for closing an argument, and epistemic coverage operates at the limits of argument closure because it minimizes dialectical exchange. Such closure works together with a shared hypothetical consideration to justify dismissal of surprising claims.

Simple extrapolation is the orthodox approach to extrapolating from clinical trials in evidence-based medicine: extrapolate the relative effect size from the trial unless there is a compelling reason not to do so. I argue that this method relies on a myth and a fallacy. The myth of simple extrapolation is the idea that the relative risk is a ‘golden ratio’ that is usually transportable due to some special mathematical or theoretical property. The fallacy of simple extrapolation is an unjustified argument (...) from ignorance: we conclude that the relative effect size is transportable in the absence of evidence to the contrary. In short, simple extrapolation is a deeply problematic solution to the problem of extrapolation. (shrink)