1. And so these men of Indostan

2. Disputed loud and long,

3. Each in his own opinion

4. Exceeding stiff and strong,

5. Though each was partly in the right,

6. And all were in the wrong!

Introduction

In recent years the thousands of international investment treaties in existence have given rise to hundreds of investor–State arbitrations. International investment law has thus become a topic of great practical importance, and one which has received significant attention in both arbitral awards and academic literature. The quotation of poetically undistinguished verse above is intended to imply, somewhat mischievously, that some of this attention has been not entirely dissimilar to the observations of the fabled (blind) ‘men of Indostan’ concerning the nature of an elephant – each perceiving different aspects of the subject at hand (for example, a tusk, the trunk, or a knee of the elephant), but insufficiently embracing the complexity of the whole (determining that an elephant is like a spear, a snake, or a tree, respectively). The complexity of international investment law is, however, not that of a whole made of variable parts (like an elephant), but of a whole which is itself open to different interpretations, which possesses inherent ‘dualities’ – a closer analogy might be with an optical illusion, a single image or object which may appear strikingly different to different viewers or from different perspectives.

The dualities of international investment law are presented in some of the most fundamental questions concerning its nature and purpose. This chapter explores the ideas or influences which lead analysis of the subject in conflicting directions and invite these seemingly contradictory viewpoints, by focusing on the ‘public–private’ distinctions or conceptions which lie at its contested foundations. These public–private dualities thus form a kind of conceptual lens through which international investment law may be viewed, and through which its different appearances or representations can be examined.