This chapter examines the interpretation practice of international investment tribunals, using the territoriality requirement in international investment arbitration as a case study. International investment tribunals employ various interpretative methods when interpreting the scopes ratione loci and ratione materiae of investment treaties. However, on many occasions arbitral tribunals use methods of interpretation that favor the object and purpose of treaties over other elements of interpretation envisaged in Articles 31–33 of the VCLT. When applied to the interpretation of the territoriality requirement, arbitral tribunals interpret the requirement based on the intention of the contracting parties to create favourable conditions for the promotion of investments and economic cooperation. Such an interpretive approach creates an expansive tendency of the territorial application of investment treaties.

The chapter analyzes the ’principle of single undertaking’ of the World Trade Organization (WTO) Dispute Settlement System (DSS). The principle of single undertaking is a unique feature of the WTO, and refers to the fact that the WTO treaty comprises several agreements all of which bind WTO members simultaneously and cumulatively, thus requiring implementation as a single undertaking. In order to maintain coherence within this single undertaking, the WTO DSS has engaged in horizontal cross-fertilization of jurisprudence across agreements. This is done by reliance on the tools and methods of treaty interpretation as defined by the VCLT rules of interpretation and their customary counterparts.

This chapter examines the collective interpretative practices of non-judicial actors, with a special focus on the One Ocean Hub. The One Ocean Hub is an inter- and transdisciplinary ocean research network that engages academic and non-academic stakeholders, including local decision-makers and representatives from international organizations, civil society, and affected communities, to co-develop mutually supportive interpretations of international environmental law, the law of the sea, and international human rights law. The interpretative practice of the One Ocean Hub related to the protection of human rights that are dependent on a healthy ocean is an example of collective interpretation whose authority comes from the expertise of the involved practitioners. The chapter examines how this expertise-based interpretation can be institutionalized under the law of treaties, with a view to embedding it in the work of relevant treaty bodies.

This is a book about the intellectual history of the later Sasanian Empire, with a particular focus on medicine, astral science (i.e., astronomy and astrology), and philosophy. It is also, necessarily, a book that deals extensively with the premodern Islamic world – not only because this is the context where most of the fundamental sources for Sasanian intellectual life take shape but also because the transition from Sasanian to Muslim rule in Iraq and Iran in the mid-seventh century CE did little to immediately and substantially impact this kind of scholarship. Particularly for the fields in focus here, a coherent intellectual-historical period can be said to extend from the sixth to the ninth century, as it is only around 800 that, owing to the raft of scholarly translations into Arabic produced under the early Abbasids, medicine, natural science, and philosophy in the erstwhile Sasanian heartland undergo a decisive shift: Greco-Roman scholarship achieves qualitatively new levels of centrality and availability, and Middle Persian and Syriac give way to Arabic as the dominant language of secular learning.

This chapter provides a detailed genealogy of the development crimes against humanity, from its nineteenth century natural law origins through its codification in the Rome Statute, and finally its possible recodification in a new treaty. It subsequently traces the interpretative approaches of states towards the current draft proposal about a specialized treaty, ultimately concluding that states’ attitudes may fall into one of three categories – unity, evolution, or diversity. Unity refers to states who advocate for the new treaty to be a horizontal add on to the Rome Statute, making the two instruments consistent as a matter of text and application. Evolution, refers to states who advocate for the progressive interpretation of existing provisions, with a view to adjusting the definition of crimes against humanity consistently with new development, or expanding the list of crimes that fall in this category. Diversity, finally, refers to the possibility of states to continue developing the law even after codification, through evolutions in customary law or diversity in national codification.

International law formation through treaties and customary international law is inherently based on a private law paradigm characterized by bilateralism and consensualism. For the most part, this private law paradigm permeates into the process of interpretation as reflected in Articles 31–33 VCLT. That said, the principle of ‘systemic integration’ enshrined primarily in Article 31(3)(c) VCLT and its customary counterpart presumes a systemic structure of international law. In this context, obligations erga omnes, jus cogens norms, and, to some extent, general principles of law provide for at least a rudimentary public law framework, which dilutes consensualism and enables a certain degree of systematization of treaty and customary law. Such systematization then takes places through the process of interpretation and, more specifically, systemic integration. Underlying this analysis is the claim that the rule of interpretation requires the systemic integration of the rules of international law ‘regardless of the source from which these rules may be stemming’

Processes of national implementation of the Rome Statute of the International Criminal Court (ICC) represent a relevant interpretive practice when it comes to this treaty. When adopting implementation legislation, states effectively offer their interpretation of the Rome Statute, sometimes diverging from the way that the ICC interprets this treaty. The chapter focuses of such examples of divergent interpretations, in order to establish whether divergent interpretations by states might influence the way the ICC interprets the Rome Statute. As an international treaty, the interpretation of the Rome Statute is governed by the rules of interpretation as enshrined in the VCLT. In light of this, divergent interpretations by states might need to be taken in consideration by the ICC in its interpretation, for example as subsequent agreement within the meaning of Article 31(3)(b) of the VCLT. Ultimately, while it remains necessary to distinguish between an interpretation within the scope of the existing law and modification of the text of a treaty, judges of the ICC may rely on the VCLT rule of interpretation in order to account for the interpretative practice of states.

Interpretation is part and parcel of every juridical endeavour. In international law, the law and methods pertaining to the process of interpretation continue to vex international legal theory and practice; in fact, increasingly so. The provisions of the Vienna Convention on the Law of Treaties (VCLT) on treaty interpretation reflect three premises which can have broader implications for the practice of interpretation in international law. First, they reinforce the idea that interpretation is, or at least can be, a formal process based on legal rules.Second, this process determines the content of rules that are ‘in force’ and is thus legally and analytically distinct from the processes of identification, modification, amendment, and termination of rules. Third, these legal rules can have a general scope of application in the sense that they can apply regardless of the nature or subject-matter of the rule to be interpreted and irrespective of who performs the interpretation. That is to say, the VCLT envisages the possibility of a law of interpretation that forms essentially ‘a unity’

The major through line in the intellectual history of late antique Iraq and Iran is its eclecticism: to a rare if not unique extent for the premodern world, the scholars of these regions drew substantially on both Indian and Greco-Roman traditions during the Sasanian and early Islamic periods. As we have seen, this eclecticism is reflected not only in the scholarly productions of this era but also in its historiography, where we find episodes such as Šāpūr II’s resettlement of Roman and Indian physicians in Khuzestan, and the comparison of Indian and Greco-Roman astronomical texts at Khusrō I’s behest.

There are four different scenarios when the institutional context of an organization is relevant in the interpretation of customary international law. Based on these scenarios, the following observations about interpretation in the institutional context can be made. Firstly, the separate institutional sphere of an organization adds a layer of normativity and authority next to that of general international law. Therefore, it may happen that instruments created by the organization would have normative effect within the institutional framework, but not per se in general international law. Conversely, a rule of customary international law could be of uncontested validity but not have normative force automatically within the institutional framework. Secondly, within the institutional framework, conduct of the organization may not be readily distinguishable from the conduct of member states. This may then influence the identification of potentially new customary rules. Finally, it seems that the institutional context is conducive to the teleological method of interpretation.