One of Bernard Williams' complaints about much contemporary philosophy was that it lacked an adequate theory of error, that it couldn't explain how it was that whole traditions of thought it rejected had gone often so seriously wrong, and that because of this, we ought to think again about its claims to correctness; if it had little or nothing to say about what it was that had made some evidently very clever people make these systematic mistakes, then what reason do we have to be sure it is not making similar ones? If you haven't thought about how in the past and elsewhere, thinkers powerful enough to have gained a reputation that ensured them a reading, not all of whom can have sold themselves, fell into error, it ought to be difficult to be confident you haven't done the same. One answer, an answer Williams himself tended to favour, was that we shouldn't necessarily expect convergence on views in subjects like philosophy; of course there are standards of success, of better and worse arguments, but because philosophy is a humanistic discipline, because it is about our relation to the world, who exactly we are matters. If we are not asking the same questions as others, whether they be figures in the history of philosophy or simply from somewhere else, we should not be troubled by the fact that they get different answers, though we may learn something from it.
One of the curiousities of Williams demanding this reflexiveness about our philosophical practice is that it's not obvious that he consistently engaged in it himself. He could be quite historically and culturally reflexive, trying quite carefully to see what it was that differentiated the questions we ask, and the context they are asked in, from the questions other elsewhere have asked and do ask. He had that kind of theory of error. What he didn't seem to have was a theory of error for all the people he accused of lacking a theory of error - though it may be that I've just missed it. These people probably made up the majority of his discipline though; for all his brilliance, Williams was, perhaps increasingly as his career went on, somewhat marginal to anglophone philosophy. That was perhaps a rather difficult position to be in though, believing most of your colleagues are deeply mistaken but not being quite clear about why. Not only is there the straightforwardly philosophical worry about how the phenomenon is explained and what an absence of an explanation means, the doubt that casts on your own reasonsing, but there's a professional and personal problem. Quite apart from the persecution complexes it is surely a spur to, without a macro-level explanation of their error, you're left with the option of giving up your view that they're wrong or assuming that they're all idiots or for sale, that the discipline you choose attracts (holy) fools and the corrupt. Surely there are things to be said at the macro-level, some of which may turn on the personalities of particular, prominent figures, but it should be said.