First and foremost "The Foundations of Legal Reasoning" reflects upon structural nature of legal reasoning in the perspective of a European ius commune; focusing on Roman, English and French law this publication provides an epistemological reflection on the discourse and methods employed by European jurists when they are involved in problem-solving and decision-making. It questions the epistemological assumption that to have knowledge of law is to have knowledge of rules and principles. In place of this thesis an institutional scheme of intelligence is proposed that is designed as a non-propositional deep conceptual model. The model provides a more convincing epistemological framework for understanding legal method since, on the one hand, it is able to function within three dimensions, thus avoiding the tendency for contradiction to be found in the two-dimensional rule model; on the other hand, it uses institutional elements (persons, things and actions) that have an existence, so to speak, in the worlds of law (science) and social fact (object of science). The model has the great advantage of embracing within its structure all of the various aspects to legal knowledge. It links all of the positive subjects with legal history, legal theory and comparative law.