I'm reading Fantl and McGrath's new knowledge book. An important thesis of the book is that of Impurism. Impurism is defined in chapter one as the denial of Purism, given thus:
(Purism about Knowledge) For any subjects S1 and S2, if S1 and S2 are just alike in their strength of epistemic position with respect to p, then S1 and S2 are just alike in whether they are in a position to know that p.
Impurism is also defined, a bit differently, in chapter two:
(Impurism) How strong your epistemic position must be -- which purely epistemic standards you must meet -- in order for a knowledge-attributing sentence, with a fixed content in a fixed context of use, to be true of you varies with your circumstances. (35)
Impurism, Fantl and McGrath think, is a counterintuitive claim; adopting it is, according to the central argument of the book, the heavy cost that is worth paying for fallibilism. I have a hard time understanding why, if it really is so counterintuitive, people find it so. I'm also far from convinced that people do find it so. Purism and impurism are technical notions that require a fairly sophisticated background in epistemology to understand. Furthermore, they are given here in terms of the far from explicit notion of 'purely epistemic standards' and 'strength of epistemic position'. What factors influence the 'strength of one's epistemic position'? Intuitively, what one knows is of great relevance to the strength of one's epistemic position, but Fantl and McGrath cannot be using the term in a way that licenses this intuitive verdict; otherwise purism would be trivially true. They must have some notion other than the intuitive one in mind. What is it? And do we really have intuitions about it?
At points, Fantl and McGrath describe the factors that count towards strength of epistemic position as 'truth-relevant' factors. (I think that DeRose also used this gloss in his characterization of 'intellectualism', which I think is just meant to be the same thing as F&M's 'purism'.) This is meant to rule in facts about the actual or probable truth of the indicated belief, and to rule out facts like what is salient to the subject or how much is at stake for her. That's some progress -- but is it clear enough? It is, I think, meant to be consistent with purism that whether a subject knows depends on whether she is proceeding responsibly in forming her belief. (It'd better be, because that's a traditional view, and purism is supposed to include that tradition.) Is this factor 'truth-relevant'? I guess it's supposed to be. We could rely on a principle like this: if a belief is responsibly formed, then it is likely to be true.
Similarly, it's meant to be consistent with purism that whether a subject knows depends on features of her environment -- even those that don't affect the truth value of her belief. For example, whether a subject knows that there is a barn in front of her depends in part on whether there are barn façades nearby. Presumably, this is roped in under truth-relevance by the effect of such circumstances on the reliability of (a certain specification of) the subject's belief-forming process, which is correlated with truth.
But if a connection that weak is sufficient to count responsibility and environmental features as truth-relevant, then it's hard to see why it shouldn't also count in knowledge, and thus, if the views developed by e.g. Fantl & McGrath, Stanley, etc. are right, make practical situations truth-relevant. Your stakes, like your environment, play a role in determining what you know, and knowledge, like responsibility and reliability, is strongly connected to truth. In what sense is such a stakes-sensitive view 'impurist'? In what sense are stakes disconnected from 'purely epistemic standards'?
I don't even understand what purism amounts to, if it's not the triviality that this line of reasoning suggests. And I certainly don't have intuitions about purism. Therefore, I have a hard time seeing what all the fuss is about. (Interesting sidenote: it looks like common ground among at least many SSI types and at least many contextualists that one of the motivations for contextualism is to maintain purism. I'm a contextualist who has never had anything like that motivation; indeed, it looks pretty incomprehensible to me.)