I think this is about semantics, actually. As far as I'm concerned "insight" = observation + analysis: as a lit professional, if I'm offering you insight about a text I'd better damned well be able to back it up with evidence, otherwise I'm just blathering, mystically or not.

And what else is "instinct", in the human sense, other than extremely fast observation and information processing on an unconscious level? I don't believe in mystical bollocks either.

Please don't hate Holmes more because of my vocab choice! - I agree that his process of observation + analysis doesn't hold water a lot of the time in either book or film, but he's a pretty endearing and compelling literary construction despite being basically unrealistic.