Abstract: Private law theory is pulled in opposite directions along many dimensions: internal and external perspectives on law; holistic and reductionist methodologies; conceptualist and nominalist views; and deontological and consequentialist approaches. Relatedly, theories tend to focus on the micro or the macro scales – interpersonal relations or societal effects – but face difficulties in relating these in systematic ways. In this paper, we examine these problems in private law theory through the lens of the legal phenomenology of Adolf Reinach. According to Reinach, the law presupposes a realm of real, timeless entitles and their workings that are synthetic a priori: they are neither conventional nor contingent. Nor are they inherently moral or customary. We argue that whether what Reinach identifies as a priori has the ontological status he claims for it, it does point toward something more robust than most current theories would countenance. We illustrate the usefulness of this perspective through Reinach’s analysis of property, transfer, and representation. Reinach’s analysis of, for example, the principle of nemo dat quod non habet (‘one cannot transfer what one does not own’) as underlying all transfer even if displaced by positive rules such as good faith purchase, captures features and generalizations that have eluded analysis. His views also point toward the importance of accessibility for legal concepts, including cases of tacit knowledge. Whatever its exact source, this “deep structure” of the law has the potential to partially reconcile some of the fissures in private law theory and to connect the micro and the macro through a better understanding of system in law.