International Relations. A self-Study Guide to Theory

particularly relevant. Only a superficial difference arises between theories of 
IR because they assume different actors to be relevant; from a philosophy of 
science perspective, the theories are the same in terms of their underlying in-
dividualist ontology. In the example of neorealist theory, as in many other 
theories of IR, the state is theoretically treated as an “individual”: it assumes 
the state is a unitary actor analogous to an individual, with a rational – state – 
interest and engaged in rational interaction with other states (as individual ac-
tors). You can find such state individualism in many IR theories. 
What these theories express is in fact the ontological position of atom-
ism/individualism you learned about in Units 2 and 3. Treating the state as if 
it were an individual actor reflects an ontological view of international rela-
tions made up of individual “units”. At the level of international relations, 
this atomism can sometimes be difficult to see. As you already know, this 
fundamental ontological position has epistemological and methodological 
implications: when the state is treated as an individual and the basic unit of 
international relations, outcomes of international politics are usually ex-
plained in the final analysis by referring to the individual state’s motivation 
and interest. You know that this approach is called methodological individu-

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alism. In IR, it is sometimes referred to as “methodological nationalism” or 
“methodological statism” because the “individual” in this case is the state. 
Generally, the question of how to treat actors theoretically in international 
politics is difficult. This holds true not only for the state, but for other actors 
as well. For example, how can we account for actors such as international or-
ganizations? How can we conceive theoretically of the UN or the EU as ac-
tors in international politics? Ontological assumptions regarding the “being” 
of collective and individual actors have important consequences for explana-
tions. This point is also closely related to the fundamental ontological ques-
tion of how the “whole” relates to the “parts”: is, for example, the UN as an 
international organization more than the sum of its constituents – the states? 
Is the UN a “collective” actor to be perceived as a collective “global commu-
nity” with a “quality” that goes beyond the sum of the individual actor’s 
(state) interests? Is “society” more that the sum of its components, the indi-
vidual societal actors? The theories presented in Part 2 of the book will be 
discussed with regard to the difficult ontological, epistemological and meth-
odological aspects of theorizing actors and their “properties”.
2.2.
Assumptions about structures 
In addition to actors, theories of the social sciences usually reflect on the 
“context” for social actions: the social environment of actors is often called 
the structural context or “structure”. “Structure” refers to the social order or 
organization within which actors act and interact. For example, “inside” the 
state, individual and collective actors (citizens, interest groups, parties, trade 
unions etc.) act within state structures. Structures are not only material insti-
tutions; they also embody the norms and rules of authority (e.g. laws) that 
govern and regulate the behavior of actors and sanction deviant behavior. 
“Outside” the state in international relations, states and non-state actors are 
usually assumed to act and interact within an international system. We have 
already discussed the fundamental assumption that the “type” of social order 
found in the international system is often perceived as “anarchy” (as opposed 
to hierarchy inside the state). The assumption of an anarchical international 
system is usually an assumption about the structural features of the interna-