B.5.FM:4.2 - Choose the participants and distinctions

Follow what can be transformed, exchanged, combined, constrained or observed. Propose the objects and relations needed to describe those changes. For a physical situation, an interaction may cross the first proposed boundary: air surrounding a vessel or a path through its casing can matter to the answer.

Try a consequential variation. If two situations receive the same description but permit different answers, recover the distinction that separates them. An object can need several quantities; several objects can sometimes be represented together. Choose the coarsening from the inference it must preserve.

For a question about permitted continuations, A.3.3 helps construct a sufficient state description. For an observation, C.16 helps connect the quantity of interest to what the observation reports.