An interesting legal argument. The crux of this would be if the emotions on display were sufficiently similar - and idiosyncratic - to count as a derived work.

An interesting legal argument. The crux of this would be if the emotions on display were sufficiently similar - and idiosyncratic - to count as a derived work. Emotions are a human universal, so it probably doesn't fly to claim that any emotions are inspired by Doyle's later Holmes work. Take, by analogy, eating; if Doyle had simply omitted to mention Holmes eating until a later work, I don't think it could be argued that any depiction of him eating is derivative of that work. If on the other hand he had specifically made a point of describing Holmes as enjoying frankfurters, which he stashed in his pocket to be consumed while on the case, then this unusual behaviour could still be under copyright. Since emotions are far more slippery than a frankfurter, this case - while likely weak - hinges on a point of literary interpretation. Disclaimer: IANAL