In this paper, I deal with how cognitive science can enrich our understanding of the ontological problem of legal philosophy by identifying and describing the cognitive foundations of law, legal institutions, and legal facts: namely, the cognitive features that human begins must possess to act in light of legal facts they believe to be existent, and hence to support the existence of these facts and their connected legal institutions. I will start with social institutions, of which legal institutions are an instance. Then I will introduce some peculiar features of legal institutions, putting forward three theses about them. Finally, I will explain how the proposed analysis, which is theoretical, can have significant practical consequences: in particular, I will argue that if legal institutions and legal facts require some cognitive capacities and dispositions, weakening the latter could entail weakening the former. This approach can lead to a cognitive-based theory of legal pathologies, the possibility of which jurists should be aware of.