History Paper

Key Differences between Classical Realism and Neo-Realism

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Classical realism, as applied in international relations, explains the patterning of social structures in a situation where anarchy exists in international politics. Realists, through a naturalist approach perceive certain interwoven patterns that determine which state plays what role, just like the laws of nature work. On the other hand, Kenneth Waltz’s neo-realism perceives political structures and the way they are hierarchically structured to determine how each state’s capabilities contribute to balance of power in international politics. This essay defines both classical realism and neo-realism with respect to international relations. It begins by also highlights the differences in the lines of thought between realists and neo-realists. Then, the differences between the two theories are pointed out.


Meaning of realism

Today, more and more philosophers continue to use the term “realism” in their written work in order to discuss matters of international relations, yet little is said about the meaning of realism (Putman, 1976). Classical realism is one of the most dominant theories of international relations today. According to Putman, 1976, whatever else realists may mean, one of their intentions is to use the term “realism” to mean “the correspondence theory of truth”. When arguing for this position, realists are opposing most of the positions held by idealists. By doing this, philosophers seem to be shifting the burden of proof to idealists.

One of the opposition arguments advanced by realists against idealism is the conception of science as some kind of miracle. On the other hand, neo-realism has been observed to be distinct from realism since its main attempt is to systemize all the insights put forward by classical realists by giving them a more solid theoretical foundation.

However, Waltz, 2003, rejects the conceptualization of neo-realism as a theory that is based on classical realism. He argues for the idea that neo-realism represents a conceptualization of contemporary international politics that is completely different from that of classical realism. Waltz, 2003points out that he understands neo-realism as a replacement of classical realism only when the former is shaped by the enduring liberal-political traditions of a country such as the United States. Neo-liberalism emerged in the United States. It is also here that this political theory thrives.

In order to understand the social world, realists use naturalism as one of the most basic principles of the theory. Proponents of naturalism argue that in many respects, international society can be studied in much the way that nature is studied. Bhaskar 1998, in The possibility of Naturalism, argues that those who are skeptical about naturalism always tend to make a big mistake by believing in the positivists’ arguments about natural science; that is, that its main aim is to try and discover universal laws that govern all the phenomena that we observe.

According to Carter and New, 2004, realists hold the opinion that the complexities surrounding human desires, ambitions, interests, and relationships can never be summarized using a set of generalizations. However, this is not to say that human social existence is chaotic. What this means is that social life is structured into many interwoven patterns that are patterned in a rough way rather than determined by a set of laws of nature (Bhaskar, et al. 1998).

Classical realism makes it possible for a distinction to be made between the knowledge that human beings have of the world (the transitive realm) and the world which happens to be an object of this knowledge  (the intransitive realm) (Carter and New, 2004). Realists hold the view that the world that is often referred to by our theories and concepts (the intransitive realm), neither constituted by, nor a product of, the theories that we have conceptualized about it.

The main aim of realists is to maintain a plausible argument in support of objectivity. This, notes Carter and New, 2004, calls for an explanatory model whereby the interplay between pre-existent structures that possess causal powers and properties, and different people, who have their own distinctive causal powers, (and hence their own unique properties), resulting in many contingent outcomes.

One of the epistemological implications of classical realism relates to the plausible defense of objectivity in everything that defines our knowledge of the physical world and the social relationships that define interactions between people. The contention by realists that truth is mind-independent continues to shape philosophical theory to this day. There is a temporal priority of all structures that make up the world as we know it. For this reason, they are completely independent of whatever knowledge we may have about them. In the realist’s perspective, the main reason why people have an inaccurate understanding of issues affecting them is that there are vested interests that cloud the truth, preventing them to access the whole truth.

In explaining the social world, realists tend to move away from happenings and phenomena. Instead, they focus on the mechanisms and structures that generate them (Carter and New, 2004). Bhaskar, 1989, talks of three main ontological domains that guide a realist’s line of thinking: the “actual”, the “empirical” and the “real”. The “empirical” is simply a subset of the actual. The “real” has elements of both “actual” and “empirical” according to Bhaskar.

Realists are also interested in circumstances that are not easy to structure or observe, but whose outcomes are known. This understanding, according to realists, is the beginning of gaining an understanding of the complexities of the social world, including international relations. Whenever they are explaining issues relating to international relations, realists have to begin with certain unstated assumptions and implicit generalizations. This may bring about a misleading explanation that arises when singular concrete events are linked together (Hooker, 1995).

Classical realism and international relations

Classical realism is an old and, indeed, a very well established theory as used to define how different nations relate with each other. Classical realism, as used in political theory is characterized by many antagonistic definitions even in traditions that are defined by authoritative defining texts such as Christianity and Marxism (Donnelly, 2000).

Commentators have argued that realism[1], as a theory, is not defined merely by assumptions and propositions; rather, it is a general orientation, some kind of philosophical disposition, a set of normative emphases that define the theory. It is more concerned with the “state of mind”, which has a distinctive flavor that is easily recognizable (Donnelly, 2000).

Classical realism, as an approach to international relations, has emerged gradually through work that is credited to different analysts who have continued to argue within the confines of the traditional approach to realism[2]. According to Waltz, 1979, with the realist tradition, success is the ultimate test of national policy; success is assessed through the extent to which a state is preserved and strengthened.

All the definitions that Donnelly, 2000 presents present a resemblance that can be said to encompass a family-type relationship that ties different conceptions of realism into a single classical tradition. Within this family, the main emphasis in classical realism refers is the constraints on politics that are imposed by human nature and more importantly, lack of an international system of government. Against this backdrop, Thompson, 1985 observes that human nature remains the same since the old days of classical antiquity. For this reason, he says, the basic tenets of classical realism remain unchanged.

Donnelly, 2000, agrees with some realists, among them Niebuhr and Morgenthau who use Machiavelli’s radical realist view[3]to come up with the view that classical realism is largely a descriptive theory. Machiavelli himself contended that any other assumption other than that there are enough egoists is a very risky one. The majority of realists according to Donnelley, 2000, are in support of the view that men are always motivated by other desires apart from the strong desire for power and that there are other aspects apart from power in issues of international relations. These desires, according to Thompson, 1985, relate to “the insatiable quest of all men for the doctrine of justice”.

Nonetheless, realists extend the conception of the tradition as one that is based on egotistic passions by adding that passions are ineradicable and that by extension, conflict is therefore inevitable. Realists plainly admit that it is profitless for a world to exist where men do not organize themselves in different for purposes of preparing for conflicts. The central political problem is egoistic passions. Therefore, statesmanship, according to realists, entails the ability to control this ineradicable aspect of human nature.

To realists, there are political necessities that are always gained whenever there is international political anarchy. As long as there is no international government, the law of the jungle will always hold (Evans, 1928). At the state level, egoistic desires are always tamed through the establishment of a hierarchical political system. In the international arena, the prevailing anarchy makes it possible for the expression of the worst forms of human nature. Whenever egoism interacts with anarchy at the international level, says Donnelly, 2000, the result is a situation whereby there is a need for international security[4] to be maintained.

Through approximation, Donnelly, 2000 comes up with a typology of six different sub-groupings of realists, namely structural realists, biological realists, radical realists, and hedged realists. For structural realists, the predominant emphasis is on international anarchy[5]. Through international anarchy, the realists argue that emphasis is put on the issue of centrality of power. Contemporary structural realists are sometimes referred to as neo-realists, owing to the “newness” as well as their views which are considered a bit different from those of classical realists (Waltz, 1979).

For biological realists, the emphasis is on the idea of a fixed human nature. A good example is Morgenthau’s argument that “social forces are born whenever human nature is in action”. He continues to explain that a social world is nothing more than human when projected onto a collective plane. This conception somehow differs from that of radical realists who argue that the three dimensions of: egoism, power politics, and anarchy. Strong realists believe that some space for non-realist ideas should exist. Therefore, for them, realism is a positive theory of international relations rather than a negative one. For hedged realists, different solutions are offered on the best solution to the problem of the state of anarchy.

Meaning of neo-realism

Neo-realism, also commonly referred to as structural realism, is a contemporary form of realism where attention is on political structures and their hierarchical patterning. Kenneth Waltz’s book, Theory of International Politics, that was published in 1979 remains one of the central neo-realism reference texts for more than a decade. Waltz was fascinated by the striking similarities in the nature of international life throughout the millennia, notwithstanding some differences in attributes as well as interactions (Waltz, 1979). After carrying out an analysis of the nature of international politics, he came to the conclusion that these similarities are as a result of a persistently structured international anarchy.

Neo-realists distinguish political structures depending on their principle of ordering (Waltz, 2003). Political actors may either be ordered according to the right order of authority and subordination or such an order may be missing. International relations, for neo-realists, mean a system characterized by anarchy, a system characterized by lack o f a hierarchy. International order, within this theoretical framework, arises from interactions between states who in the formal sense are equal political actors.

Differences between neo-realism and realism

The meaning of neo-realism contributes to a better understanding of the differences between international relations and comparative politics through the definition of different constraints, rules and opportunities of hierarchic and anarchic structures. Neo-realists also define the relationship that exists between units based on differentiation and functions. For instance, in a hierarchical order, the relationship between super- and subordination defines the differences between different units (Waltz, 1979).

According to Rengger, 2000, Waltz thinks that a theory of international politics should systematic, while theories of foreign policy, in sharp contrast must be reductionist. This sets the stage for a discussion of differences between theories of international relations and theories of foreign policy. However, admits Rengger, 2000, is that all the theories of international politics[6] that Waltz discusses have a reductionist element in that they fail to appreciate the distinctions that he puts forth or even their theoretical implications.

The principal differences that make each state unique are their capabilities and not their function (Donnelly, 2000). The tasks that all states perform all the time or try to perform are always very similar (Waltz, 1979). Waltz makes a very compelling distinction between national relations and international relations, thus; national politics are made up of differentiated units that perform specified tasks while international politics are made up of like units, each of which tries to duplicate the functions of the other.

To further distinguish neo-realism from realism, Waltz talks about differences in the distribution of capabilities among different units of states. Whereas in realism international order is considered as anarchic, owing to lack of differentiation of functions of different states, in neo-realism, international political structures of different states are easy to distinguish from each other by simply using the yardstick of capabilities[7] (Waltz, 2003).

            Unlike realism, the central tenets of neo-realism have been somehow changing. Waltz, 2003 talks about the inevitability of balance of power, an aspect that was missing in his 1979 book, Theory of International Politics. Waltz conceives the balance of power as the main tool of statecraft, and that the “ordering principle” forces all states to become like players on the international arena. However, neo-classists appreciate that states are not the sole participants in the international political arena (Rengger, 2000.

            The neo-realist agenda has undergone many modifications since its conception. When it was first proposed by Waltz in 1979, the emphasis was mainly in political structures, the units therein, and how the features of these units determine the role that each state plays in international relations. This is the main reason why the theory acquired the name “structural realism. Latter-day generation of structural realists introduced more elements of sophistication, and ended up christening the theory “neo-realism”. Although the sophistication lies abstractly within the lines of thought that Waltz had conceptualized, the ideas expressed seem to be drifting away from the initial tenets of structural realism (Rengger, 2000)

            Donnelly, J. 2000 refers to the new lines of sophistication introduced by Stephen Walt, a “third generation neo-realist” who was trained by Waltz. In Walt’s first book, Origin of Alliances, he recasts neo-realism by stating that balance of power is never an effort against power, but rather an against perceived threats. He further argued that the perceived threats constitute the functions of perceptions of intent, aggregate power, and offense-defense balance (Rengger, 2000).

According to Rengger, 2000, the main difference between neo-realism and realism lies in the issues of order and balance. Neo-realists do not give much attention to the thorny problem of order in the way realists do. Neo-realistsare is interested in new methodological assumptions that define relations between states. In the course of defining these assumptions, it seems that the position that ‘states are not the only actor’s international relations’ is verified. Waltz, 1979 criticizes Aron because of the latter’s claim that the field of international relations is resistant to a theory of any kind, including the type that Waltz propounds. Aron (cited in Rengger, 2000) claimed that Waltz’s theory contains diverse subject matter (Most of it both normative and explanatory), in order to locate the problem of order. This way, Waltz reduces “theory” and focuses, instead of on the “explanatory”. Aron, therefore, argues that such a discussion is not a good account of order; that it only acts as a mere description of the patterns that can be discerned in the theatre of international relations.

The explanatory aspects of neo-realism were used to describe the U.S-Soviet alliance during World War II. This was a case of two international adversaries being brought together in order to fight a common enemy. After the way, the U.S and the Soviet Union became morbid rivals once again (Donnelley, 2000). Whenever two explain the concept of balance of power, neo-realists cite the situation whereby dominant powers face each other. In this case, each state perceives the other of threatening its security and therefore the powerful states can only be enemies. In this situation, each of the powers has to balance its power relative to that of the adversary, regardless of its own political inclinations and preferences.

Although neo-realism, as propounded by Waltz has a provision for the existence of internal differences among various states, it completely abstracts every other aspect of the state except its capabilities. The main reason for this approach is that the anarchic nature of international relations can only be accurately defined in reference to the capabilities of different states. To explain this argument, Waltz, 1979 argues that “a state may behave in whatever manner it chooses to, but the state can only be rewarded if the behavior responds to structural pressures. If the behavior fails to respond to these structure pressures, it is punished” (Donnelley 2000).

Kratochwil, F. 1993 points out that it is easier to explain the changes brought about by perestroika (dissolution of the Soviet Union), the reunification of Germany and the end of Cold War through realism rather than neo-realism. First, Kratochwil notes that neo-realists suffered a major embarrassment caused by the chain of events that led to the end of the Cold War era. To begin with, they were very accustomed to explaining changes through reference to shifting growth patterns or inherent distribution of capabilities.


However, the events of 1989/1990 were not occasioned by any such redistribution. For instance, the soviet military was the same way only one year before the fall of the Berlin Wall. Furthermore, all these changes had taken place in an unexpected manner, in that a hegemonic war did not break out. It appears that the international changes that characterized the end of the Cold War were brought about by domestic political changes rather than systematic factors such as the democratization of Eastern Europe.

In addition, neo-realism seemed to lack the conceptual apparatus to explain the nature, direction, and scope of change (Burchill, 2005). This failure by neo-realism made realism seem more suited to explaining the changes in international relations. Moreover, the contention by realists that “the strong often do what they can while the weak suffer what they must” seemed to find justification in the events of 1989/1990. However, the weak were realizing that there is a limit to what they “must” suffer while the strong was realizing that what they “can” do was much different from the repertoire of daily hustle and bustle of international politics. Neo-realists were at pain comprehending either phenomenon (Kratochwil, 1993).


Both classical realism and neo-realism are relevant as far as a proper understanding of international politics is concerned. For classical realists, a naturalist approach is taken to explain how the inherent desire for power drives individual states into pushing agendas in an anarchical international atmosphere. For neo-realists, the emphasis is on how different states operate in international politics depending on capabilities in order to deal with perceived threats.


Bhaskar, R.1998. The possibility of Naturalism: A Critique of the Contemporary Human Sciences (Third Edition). London: Routledge.

Bhaskar, R. et al (Eds). 1998. Critical Realism: Essential Readings. London: Routledge.

Burchill, S. 2005. Theories of International Relations. London: Palgrave Macmillan

Carter, B. and C. New, (Eds.) 2004. Making Realism Work: Realist Social Theory and Empirical Research. New York: Routledge.

Donnelly, J. 2000. Realism and International Relations, Cambridge: Cambridge University Press.

Evans, L. 1928. New Realism and Old Reality: A Critical Introduction to the Philosophy of the New Realists. Princeton: Princeton University Press.

Hooker, C. 1995. Reason, Regulation, and Realism: Toward A Regulatory Systems Theory of Reason and Evolutionary Epistemology. New York: State University of New York Press.

Kratochwil, F. 1993, The Embarrassment of Changes: Neo-Realism as the Science of Realpolitik without Politics, Review of International Studies, 19(1), 63-80.

Putnam, H.  What Is “Realism”? Proceedings of the Aristotelian Society, New Series, 76, (4), 177-194.

Rengger, N. 2000. International Relations, Political Theory, and the Problem of Order: Beyond International Relations Theory? London: Routledge.

Shimko, K. 1992. Realism, Neorealism, and American Liberalism, The Review of Politics, 54(2), 281-301.

Thompson, K. 1985. Righteous Realists: Political Realism, Responsible Power, and American Culture in the Nuclear Age. New York: Routledge.

Walker, R. 1987. Realism, Change, and International Political Theory, International Studies Quarterly, 31(1) 65-8.

Waltz, K. 2003.Realist thought and neorealist theory. Journal of International Affairs 5(3), 15-35.

Waltz, K. 1979. Theory of International Politics. New York: McGraw-Hill.

[1] In this case, the term “realism is used in reference to “political realism”.

[2] Nardin and Marpel, 2002 present a good reading into different ideas relating to traditional thoughts on international relations.

[3] Machiavelli believed that politics and immorality were inseparable (1970: Book 1, ch.3).

[4] According to the term “international security” to realists means a world that is somewhat less violent and less dangerous, as opposed to a world that is completely safe.

[5]In international relations, the term “anarchy” in its literal sense, means a lack of government or absence of rule.

[6]Walts engages in a discussion of Morgenthau, Richard Rosecrance, Aaron and Morton Kaplan.

[7] In neo-realism, some states are considered to have more capabilities than others, such that each state can be uniquely defined by considering its unique capability.

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