> The science of deduction as he's supposed to apply it in the stories would actually require rather encyclopedic knowledge of many different topics in order to

> The science of deduction as he's supposed to apply it in the stories would actually require rather encyclopedic knowledge of many different topics in order to understand the wide array of humans he's supposed to be reading --- I partly disagree with this. You live with people. A trained person can learn to detect differences - of gestures, habits, behaviour - far more easily, and would not require the broad knowledge that computers need for effective pattern-matching and deduction. (And since Holmes is doing his detective work constantly, he would have been honed and trained enough for that sort of thing.) That Holmes is ignorant of mainstream things - whilst being extremely conversant in the eclectic - does not necessarily impair his deductive abilities. After all, deduction is just the ability to tie facts after facts and event and event - and to trace effect to causation. Deducing who might have done something seem entirely within the realm of possibility and limits of Sherlock Holmes' knowledge, given that the evidence he looks into often makes a look of sense in context. (Now, deducing motive is a different thing altogether - no one really knows what's in the heart of men.)