 What, then, of the legal utterances “occurring in a textbook of law”? Are these assertions or directives? At a surface level, Ross tells us, the language in such books will often be similar or even identical to the language in an actual statute: a doctrinal writer might, for example, say that certain behavior “gives rise to liability” or “shall be punished.” But we should not be misled by this surface similarity, Ross says: “the propositions in a textbook, at any rate to a certain extent, intend to describe, not to prescribe” (1959, p. 9). To that extent, therefore, they must be assertions, not directives—specifically, Ross claims, assertions about what is valid law.