The paper critically engages with the argument that competition law functions as a socially constructed power structure. In doing so, it examines competition law as a system dealing with legal and empirical facts. It develops the theory of competition law system as the sum of multiple choices of exclusion and inclusion being shaped by several inconsistent determinants such as the basic legal structure, politics, science and culture. The paper demonstrates how these choices are triggered by cycles of epistemological re-examinations, which are either practice-oriented or fueled by broader socio-economic or political events.