It’s every man’s business to see justice done.

The line asserts a civic, not merely professional, duty: justice is not something to be left solely to courts, police, or lawyers, but a responsibility shared by all members of society. Read in a Doyle context, it resonates with his recurring theme that moral clarity and public-spirited action must supplement formal institutions—an idea dramatized in detective fiction where truth emerges through individual initiative. The aphorism also implies that passivity enables wrongdoing: to “see justice done” is to take notice, speak up, and act when necessary, even when it is inconvenient. Its force lies in shifting justice from an abstract ideal to an everyday obligation.