A Structural No-Go Statement on Unbounded Physical Effectiveness

This paper formulates a structural no-go statement on unbounded physical effectiveness. Under minimal and widely accepted assumptions of consistent physical description, it is shown that an unbounded counting of physically effective contributions cannot be formulated without contradiction. The work introduces neither new dynamics nor a new physical theory. Instead, it makes explicit a necessary structural constraint that is already implicitly realized in all consistent physical descriptions under extreme conditions. This work constitutes Part I of a three-part series on physical effectiveness and structural consistency. Follow-up papers further develop the Effectiveness Principle and apply it to a concrete trans-Planckian consistency test.