The present study addresses the requirements that must be met when analyzing tax effects in the context of financing decisions. The author demonstrates that the theoretical explanation of the influence of taxation on individual behavior, based on neoclassical tax effect hypotheses, does not suffice for a critical-rational understanding of explanation, but is compatible with a methodologically instrumentalist understanding. The methods of empirical testing are fundamentally associated with both positions, provided that certain modifications to the prevailing research practices are made.