La frontera entre hecho y derecho: La norma jurídica extranjera como supuesto fáctico

As regards legal reasoning there is a clear divide between proving the existence of legal norms and proving factual situations, even such as involve rights and duties provided they are the outcome of extra-legal data. Foreign law is to be regarded as one of those data whenever it is applicable in virtue of rules of private international law. In this essay we go into several issues related with the sacaling of connection points, proving the content of applicable foreign law and the epistemological problem of the translatability of alien legal concepts. We try to solve the ensuiing difficulties by dint of both a logic of firsts of truth and a deontic logic of legal situations, which applies not just to the inner legal order but also to rights and duties derived from private or foreign sources.