Sublime

What separates Holmes from Watson, the passive observer from the active one, engaged passivity from disengaged activity, is precisely the descriptor I’ve used in both cases: engagement. Flow. Motivation. Interest.

This Sherlock, who self-identifies as a sociopath, likely because he so nakedly prefers technology to people, seems to have both a biological and synecdochal relationship to his PDA.

Secondly, Watson can be intimately familiar not only with my entire genome and my day-to-day medical history, but also with the genomes and medical histories of my parents, siblings, cousins, neighbours and friends.

Watson serves as a constant reminder of what errors are possible. As Holmes puts it, “In noting your fallacies I was occasionally guided towards the truth.” And that is no small thing. Even in asking the smallest questions, ones that seem entirely obvious to Holmes, Watson nevertheless forces Holmes to look twice at the very obviousness of the thin

However, it is made clear in the final confrontation between Moriarty and Sherlock that Sherlock's one weakness is John,because John is the only person whose endangerment finally makes Sherlock visibly upset.

Rogers was, in Isaiah Berlin’s classification, a hedgehog: He knew one thing, but he knew it so well that he could make a world of it.