Constitution of Acts Through Shared Practice: Why the Same Movement Counts as a Particular Institutional Act Only Within a Practice

This conceptual paper introduces Constitution of Acts Through Shared Practice, the relation through which an observable movement or mark counts as a valid institutional act under the rules of a shared practice. Participants, procedure, and timing can be conditions of validity that the physical movement alone does not establish. The paper distinguishes detecting a movement, determining whether a valid act occurred, and deciding whether to count or recognize it officially. Official acceptance can be mistaken, and not every rule governing conduct is a condition of validity. Where governing rules are disputed, closer inspection of the movement cannot by itself resolve the dispute. The discussion connects the relation to Rawls’s practice conception of rules and examines the Florida ballot recount described in Bush v. Gore. The case shows how official counting varied with the standards applied. It does not establish that every rejected ballot lacked a valid vote, and the paper takes no position on the election outcome. Part of the Constitution, History, and Standing series within On Human Modeling, the paper offers questions about which practices make actions count and who certifies their validity. Its framework can inform human–AI research on whether systems distinguish observable inputs from valid approvals, commitments, or other institutional acts.