International Relations. A self-Study Guide to Theory

particular theories of International Relations. It is important to emphasize 
once again that the discussions in Part 2 of the book will be based on “learn-
ing by example”: the broader intention is to offer meta-theoretically and phil-
osophically informed guidance for your structured self-study of any IR theory 
– not only those presented in the book. The application of this concept will be 

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demonstrated by way of five sample theories. The method is based on the 
conviction that a structured learning process along the lines of criteria de-
rived from philosophy of science discussions will offer important insights on 
theory construction that, because of a neglect of their embedding in philoso-
phy, would otherwise not be reached.
As this learning unit is basically about the didactics and method to be ap-
plied in Part 2 of the book, there will be only one self-study instruction and 
two review questions. Key aspects will be given in form of a tabular over-
view of the criteria developed in this unit. 
Criteria for a structured learning process about theories of IR 
1.
Core question 
Each learning unit dealing with a particular theoretical approach will start by 
asking: what is the core question or core problem of the approach? Which 
phenomena of international politics does the theory explain? What is the pur-
pose of constructing this particular theory of IR? 
An introduction of different theories of IR with regard to their core ques-
tion will offer a first and important insight on the understanding of the under-
lying theory and science. 
2.
Ontological assumptions about actors and structures in 
international relations 
As you have learned in Units 2 and 3, theoretical constructions in the social 
sciences are always built on assumptions: ontological, epistemological, and 
methodological starting points in the process of theory construction.
For a theory of International Relations these are usually assumptions
(1) about the relevant actors of international relations, the “type” of actors 
considered to be most important and their “properties”; 
(2) about the context of interaction, that is, the structures of international re-
lations;
(3) about interrelations between the entities; how the actors and structure re-
late to each other. 

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You know that these are ontological assumptions as long as they involve 
claims about existence and being (what is), the entities that exist, and their 
properties and relations. They are epistemological assumptions insofar as 
they concern questions of how to come to know and what counts as valid 
knowledge. They are methodological assumptions when they relate to the 
ways and methods in the practice of gaining knowledge. 
Let me now elaborate on what we are looking for in IR theories when ap-
plying the criterion of “assumptions about actors and structure”. 
2.1.
Assumptions about actors 
In order to reflect on the politically relevant interactions, a theory will usually 
ask about actors. Who are the relevant actors in international politics? What 
is the “nature” of the actor and what is the “nature” of interactions taking 
place? 
Remember that the answers to these questions are “starting points”, not sub-
ject to any “proof”, but instead fall under the category of what we call “as-
sumptions”. An example is the general assumption that the “nature” of interna-
tional relations is inter-state politics, that states are the central and most im-
portant actors, and that they act rationally. This is a claim shared by the most 
influential theoretical approaches in IR. However, other theories exist as well, 
starting for example from the assumption that the “nature” of international poli-
tics is a world of interwoven, network-like social relations between diverse 
types of actors within a “global society”. Here, any social actors, state and non-
state, are relevant for the “existence” of international relations. For each exam-
ple, the view of the “being” of international politics – the view of ontology – 
differs. This difference – whether you think of international relations as state 
interactions within a system of states or, alternatively, have a world society in 
mind when talking about “international relations” – affects both the theoretical 
construction and the explanatory model that a particular theory offers.
The precondition of action and interaction between social actors is usually 
perceived as an intentional state: action is, by its very nature, intentional and 
purposeful (even though, of course, it can have unintentional effects and con-
sequences). Therefore, theories usually make assumptions about the “driving 
forces” of actions/interactions and about how actors reach decisions. These 
are ontological assumptions related to the actor’s motivation, goals, needs, 
cognitions (such as values, beliefs, attitudes, knowledge, and perceptions), in-
terests or preferences; in short, they are ontological assumptions about actors 
and their “properties”. 

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110 
For example, many theories in IR draw on action theory and assume actors 
are “rational actors”. For rational actors, the “source” of action is assumed to 
be “internal” (their “interest”) and to involve utility-maximization, which is 
perceived as being a “property” of the individual actor. With regard to an ac-
tor’s decision-making style, utility-maximization assumes that actors have in-
dividual preferences for various possible outcomes in any situation and, as a re-
sult, can rank the outcomes in terms of their desirability. They then choose 
whatever strategy or course of action makes the better outcomes most likely, 
thereby maximizing the actor’s “utility” (rational choice). You will find such 
assumptions in economics as well as in most other social science theories. 
Those theories that draw on mathematical models of decision–making in a 
formal manner demonstrate individualism and the rational actor-assumption 
most clearly. Examples are decision theory, which focuses on single decision 
makers, and game theory, which focuses on small groups of actors interacting 
strategically (for a good overview of rational choice in IR see Kydd 2008). 
In line with these ontological assumptions, IR theories assuming rational 
actors ultimately explain outcomes in international politics in terms of the in-
dividual actors’ rational actions. Depending on the particular actors assumed 
to be relevant for international relations (these could be individual actors 
from a state’s society as is the case in liberal theory, or unitary states as in 
neorealist theory), different theories of IR operate on the general assumption 
of rational individual actors. Here, philosophy of science discussions become