Our intramural, often scholarly, but not always polite, debates about the legitimacy of invasions directed against more-or-less brutal authoritarian governments demonstrate how one’s preferred conception of the nature of law can affect one’s conclusions about its contents.
The celebrants of what I will call the classical view display the following characteristics: while recognizing that states can establish and alter norms through both explicit agreements normally expressed in written texts and implicit agreements manifested in practice, they tend in their epistemology toward a rather strict separation of these two processes; when attempting to identify norms arising from explicit agreements, they presume that the parties had an original intention which can be discovered primarily through textual analysis and which, in the absence of some unforeseen change in circumstances, must be respected until the agreement has expired according to its terms or been replaced by mutual consent; when attempting to identify norms arising from implicit agreement, they rely primarily on relatively formal manifestations of consent, deemphasize the relative power of states, and imply a high threshold below which alleged norms are entirely without legal character.