On one important notion of irrelevance, evidence that is irrelevant in an inquiry may rationally be discarded, and attempts to obtain evidence amount to a waste of resources if they are directed at irrelevant evidence. The familiar Bayesian criterion of irrelevance, whatever its merits, is not adequate with respect to this notion. I show that a modification of the criterion due to Ken Gemes, though a significant improvement, still has highly implausible consequences. To make progress, I argue, we need to adopt a hyperintensional conception of content. I go on to formulate a better, hyperintensional criterion of irrelevance, drawing heavily on the framework of the truthmaker conception of propositions as recently developed by Kit Fine.
KeywordsRelevance Hyperintensionality Partial content Truthmaker semantics
The research for this paper was funded by the Deutsche Forschungsgemeinschaft (Grant KR 4516/1-1), and I gratefully acknowledge the support. An earlier version of this paper was presented at a research colloquium at the University of Hamburg. I thank the members of the audience for their comments and criticisms. Special thanks are due to Sebastian Krug and to my fellow phlox members Michael Clark, Yannic Kappes, Martin Lipman, Giovanni Merlo, Stefan Roski, Benjamin Schnieder, and Nathan Wildman. I have also greatly benefitted from a number of conversations with Kit Fine on the general topic of relevance and truthmaker semantics. Finally, I would like to thank an anonymous referee for this journal for some very helpful comments and suggestions which have resulted in a number of improvements.
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