One of the most influential arguments in favour of perdurantism is the Argument from Vagueness. The argument proceeds in three stages: The first aims to establish atemporal universalism. The second presents a parallel argument in favour of universalism in the context of temporalized parthood (‘diachronic universalism’). The third argues that diachronic universalism entails perdurantism. I offer a novel objection to the argument. I show that on the correct way of formulating diachronic universalism the principle does not entail perdurantism. On the other hand, if diachronic universalism is formulated as Sider (incorrectly) proposes, the argument fails to establish his principle, and thus perdurantism.

When interpreted, sometimes treaties have to go through a trial by fire and are found either to be ‘living instruments’ evolving alongside the relevant changes both in law and in facts or to have a ‘fixed’ meaning. The aim of the present article is to examine how intertemporal considerations find their way into the interpretative process and what the effects are on the treaties being interpreted. Do these changes in law and fact actually change the treaty itself, or do they merely trigger a latent quality already existing in the treaty itself? Does time change the treaty, or does it merely ‘unfold’ it? This question will be examined through the lens of the main philosophical theories on identity, persistence, time and change (endurantism, perdurantism and exdurantism), and by focusing on the ‘direct’ (principle of contemporaneity and evolutive interpretation) and ‘indirect’ (Article 31(3)(c) and the intertemporal application of the rules of interpretation) points of entry of intertemporal considerations in the interpretative process. Through this examination the elements that weigh upon the judicial interpretative process and tip the scales either in favour of an evolutive interpretation or in favour of the principle of contemporaneity, will be identified, as well as the limits of any such interpretation. In this manner, an answer will be arrived at as to whether, from an interpretative perspective, treaties endure, perdure or exdure.