I have been somewhat interested in a confusion that I've seen a lot recently, between the two following descriptions (or their equivalents):
(1) Knowledge of a system of beliefs S
(2) Treating S as a system of knowledge
The confusion involved here is between 'S as a thing known' and 'S as (a system of) things known'. The two are not at all the same. Someone could have knowledge of a system of beliefs they consider completely wrong; for instance, I could acquaint myself with the beliefs of astrologers in order to refute them more thoroughly. Situations that require me to know the beliefs of astrologers do not thereby require me to consider astrology a legitimate body of knowledge. I do not have to put any trust in horoscopes in order to know what people do when they practice horoscopy; this is simply a matter of research, not astrological practice. You can be an expert on ancient Greek religion without being a devotee of it; you can do respectable research into the worship of Moloch without trying your hand at immolating children. Urging someone to come to know a system of belief is not the same thing as urging them to treat the system of belief as a system of knowledge. That would be a conflation of the object of knowledge with knowledge itself.
What puzzles me is why anyone would fall into this confusion in the first place. It's not a very difficult confusion to avoid, if we aren't engaging in massive equivocations; there are plenty of obvious parallel instances where people can know what's in S without taking S as a body of known truths; an epistemology in which you couldn't know any falsehoods -- even to know that they are false, and the ways in which they are false -- would be a very peculiar epistemology indeed. Perhaps it has to do with thinking that only truths are known, without recognizing that even when dealing with false claims and beliefs there are truths about those false claims and beliefs that can be known.
