An Antinomy in Alexy's Theory of Balancing

This article argues that Robert Alexy's influential theory of balancing is affected by a contradiction that makes it unfeasible as an instrument by which to explain some aspects of law and legal reasoning it aims to clarify. In particular, I will show that one of the premises of Alexy's theory of balancing is incompatible with its conclusion. Alexy's theory is based upon a sharp distinction between rules and principles. However, as my analysis will demonstrate, its conclusion implies that it is impossible to distinguish between rules and principles. This is because the so-called weight formula and the law of colliding principles (i.e., the two main notions used by Alexy to explain balancing) cancel out any difference between these two types of norms.