3.1: Introduction

Learning Objectives

By the end of this chapter, you will be able to:

• Articulate the meaning and significance of scientific theory.
• Identify and explain the core assumptions of realism and their implications for explaining processes in international relations.
• Trace the historical roots of realism as a theoretical approach.
• Critique realism’s explanatory strengths and weaknesses.
• Analyze and illustrate important concepts within realism, such as the security dilemma, by providing historical or contemporary examples.

Scientific theory, as a concept, differs radically from the everyday use of the term “theory.” Most people tend to think of a theory as an unproven guess or a supposition. For example, if someone says, “I have a theory about why the traffic is bad today,” they are likely offering an untested, personal hypothesis based on limited observations. In science, however, theories are well-substantiated frameworks that explain observable phenomena based on hypotheses, evidence, and thorough testing. As such, a theory serves as a “proven” (for lack of a better word) explanation of a particular question or puzzle. It is never fully finalized, however, and theories remain open to retesting and reevaluation. A theory’s strength lies in its ability to adapt and evolve with new data. In fact, it is the very process of continual testing and retesting that distinguishes a scientific theory from a mere guess. Examples from the world of sciences include the theory of evolution, the theory of relativity, and cell theory. Each of these provides a comprehensive and well-supported explanation of its respective natural phenomena. Yet, each remains open to modifications as new evidence and research deepen our understanding of these phenomena.

In the social sciences, including the field of international relations, we aspire to the same level of rigor and comprehensiveness. Unlike the natural sciences, however, theories within international relations often deal with complex forms of human behaviors and societal structures that are not readily testable within controlled environments. The objective nonetheless is the same: Researchers aim to create theories that systematically explain evidence-based patterns and processes in international politics. These different theories try to answer a variety of questions on a scale from big, wide-ranging questions (e.g., Why do wars start? How can we achieve global peace?) to smaller, more narrow questions (e.g., Why, or when, are diplomatic negotiations successful? How does economic interdependence affect state behavior?).

Take, for example, the Democratic Peace Theory. While we will cover this theory in detail in Chapter 4, in short, the theory posits that democracies are unlikely to go to war with one another. Historical evidence supports this theory; empirical evidence shows that, over time, democracies tend to avoid conflict with each other. Yet this theory is also constantly reevaluated in light of new political developments and data. Just like theories in the “hard sciences,” theories in international relations undergo ongoing testing and refinement, often using case studies, statistical analysis, and historical comparisons to develop their explanatory power.

Because international relations deals with human behavior, theory development is not a straightforward proposition. As researchers try to explain how states interact on the world stage, they must take into account many variables, such as the diversity of global cultures, political systems, and economic conditions (among many others). This variety means that, while theories provide a general framework, their application may differ across different geopolitical contexts. For example, the way economic interdependence shapes relations between Western democracies might differ significantly from how it impacts relationships between developing nations in the Global South. As such, theories in international relations must aim for a balance between offering broad, universal explanations and allowing for specific, context-based variations. In addition, scholars of international relations should remain committed to the idea of constant testing and evolution (something known as “falsifiability,” which is the ability to test and potentially disprove a theory). This process of constant scrutiny, debate, and empirical validation reinforces a theory’s credibility.