Scottish philosopher Thomas Brown — not the more famous Reid, but his overlooked successor at Edinburgh — distinguished between two kinds of mental association: those formed by mere contiguity (things that happened near each other) and those formed by resemblance (things that share a structural pattern). Most habits are built on contiguity: you always run at 7am, always in that gear, always on that route. But Brown noticed something unsettling — contiguity-based bonds are secretly parasitic on circumstances you don't control. Resemblance-based bonds are portable. What this means for a habit you've built carefully is that the deepest version of it isn't 'I do this thing at this time in this place' — it's 'I am the kind of person who responds to this type of situation in this way.' The runner who trains only on flat morning roads has a contiguity habit. The runner who has practiced on hills, in rain, in the afternoon, in new cities, has something closer to a resemblance habit: a pattern that recognizes itself across varied surfaces. Brown's insight, combined with what memory researchers call 'varied encoding' — the documented finding that retrieving a memory across different contexts strengthens its underlying structure — suggests your next step isn't adding a new habit. It's deliberately exposing your best existing habit to one unfamiliar context, so it learns to recognize itself there too.

Think of your most reliable habit — the one you'd say is truly 'yours.' If you stripped away the specific time, place, and gear associated with it, what would actually remain?

Drawing from Scottish Philosophy of Mind (Thomas Brown) synthesized with Cognitive Memory Science (Varied Encoding Research) — Thomas Brown — Lectures on the Philosophy of the Human Mind (1820), on the laws of suggestion and the distinction between contiguity and resemblance as associative bonds