This essay addresses the relationships between prescription and description in legal rules. The analysis will focus on the culture-laden connotations of factual categories implied in all legal sentences and/or provisions. This investigation is spurred by the need to assess the impact of cultural difference in people’s understanding of legal imperatives and, symmetrically, how that impact is to be considered in the application of law. Differences in ways of categorizing the world could position the cultural pre-understanding required by law, and the (...) pluralism recognized and protected by constitutional principles and human/fundamental rights discourse, at a crossroads. Hence, even when we find an illegitimacy or an ignorance about what legal rules do not explicitly state but instead implicitly presuppose, this does not exclude that behind that ignorance there may be something worthy of legal protection. A question emerges: is it legitimate and reasonable to consider the ignorantia facti resulting from differing ways of categorizing the factual world as automatically and uncritically subject to the principle ignoratia legis non excusat? The essay continues with an assessment of the possible consequences of ignorantia facti in the administration of justice in multicultural societies and migration contexts. For this purpose, the opportunity for an intercultural use of law—including within national law—will be considered as a means of avoiding the discriminatory application of ignorantia facti. This topic will be addressed by leveraging both semiotic and cultural-anthropological analytical tools, including the well-known greimasien “contrat de véridiction”. (shrink)