Reverse Engineering Epistemic Evaluations*

Abstract

What is the function of words like ‘irrational’ as used in ordinary epistemic evaluations? I’m thinking of simple evaluations: criticism like ‘Smith’s belief that Obama’s a Muslim is irrational’ or praise like ‘Green’s belief that all humans are mortal is rational’. We don’t make such claims just for the sake of it, just for fun, or for no reason at all. So what is the real point or purpose of this epistemically evaluative aspect of our linguistic practice? It must have some utility, but what? What would we lose if epistemically evaluative words suddenly disappeared from our vocabulary?1 The question requires some motivation, since discovering a word’s function doesn’t necessarily call for armchair philosophy. Some words might ∗I pronounce it, when speaking English, like this: sin ·on dor ·uh·mudge·uh. The question of this paper thus contrasts with the timeworn questions of how to give necessary and sufficient conditions for this or that philosophically interesting property. There are, however, a few excellent philosophical explorations of the function of this or that philosophically interesting word or concept. In philosophy of logic and language, Quine offered an elegantly simple insight about the utility of the truth predicate which precipitated the contemporary development of deflationism about truth; see Quine (1970), Leeds (1978), Horwich (1990/98), and Field (1994). In metaphysics, a series of recent papers on modality have broached the fascinating issue of the function of modal concepts; see Kment (2006), chapter 5 of Williamson (2007), and Divers (2010). In epistemology, there is Edward Craig’s wonderful and underappreciated book, Knowledge and the State of Nature, Craig (1990). Some recent work by Steven Reynolds, brought to my attention only after this paper was given at the Rutgers Epistemology Conference, is closely related to Craig’s project; see Reynolds (2002). Though Craig and Reynolds write about knowledge rather than rationality or justification, there are obvious common themes and specific points of contact between their views and the view I will be developing. The most notable common theme is the general importance we assign to the role of testimony in the function epistemic language. One major difference, since they write about knowledge and not rationality, is that their views are not designed to explain the puzzle I will be raising shortly.