Thanks to Professor Lebow for an engaging review of International Relations’ Last Synthesis. He highlights the core argument of the book, one in favor of theoretical diversity and openness. In doing so, though, he posits ontology as having a more central role in the argument than is our intent. As he notes, the book does indeed claim that the common feature across self-described constructivisms is ontological, the assumption that political reality is socially constructed rather than materially given. However, this is in no way a claim that ontology is the principal conceptual basis for comparison of theories more broadly. The term “theory” is sufficiently broad, meaning so many different things in different contexts and to different scholars, that any claim that there is one way to compare across theories is misplaced, whether the basis for that comparison is ontological, epistemological, or something else.

Different understandings of theory are often simply orthogonal to each other. This is in a way our point in arguing against a constructivism-critical theory synthesis; the two conceptual categories are orthogonal to each other, and therefore can reasonably interact or not within specific research projects as appropriate to those projects. In fact, we argue at length that critical theories do not have a common ontology. What they have in common is the idea that theory in the social sciences is inherently political. This idea is compatible with but in no way inherent to an ontology of social construction.

Nor do we make this claim about constructivist ontology as an exercise in inclusion and exclusion, an argument about who is or is not legitimately a constructivist. Our claim is that self-proclaimed constructivists’ descriptions of what they do are generally consistent with an ontology of intersubjectivity and co-constitution. We are not in the business of saying who is or is not a constructivist (or critical theorist, or any other kind of “-ist”); anyone who chooses to describe themselves as a constructivist (or critical theorist, etc.) is, from our perspective, welcome to the moniker.

More broadly, we speak in terms of various theories of and approaches to the study of global politics as each offering its own affordances, understood as the potential uses that are latent in and can be expressed through specific intellectual tools. The key affordance of constructivism writ large is tools for thinking about the social basis of political activity; of critical theory, the political basis of social theory. Thinking in terms of the affordances of intellectual tools, rather than in terms of competition among theories or paradigms, helps to highlight how various tools can be used in tandem in a specific intellectual project as appropriate to that project. This claim is intended specifically as an argument against the disciplinary tendency in IR to think of theories and paradigms as either mutually exclusive or as interrelated in any fixed and necessary way. It is intended to help enable scholars to think more creatively about how to use the various intellectual tools available to use in the study of global politics. We agree with Lebow that disciplinary gatekeeping hinders such creativity. But we argue that making the intellectual case for such creativity is worthwhile, nonetheless.