The Political Realism of Thucydides and Thomas Hobbes

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The Realist school of thought in International Relations has claimed both Thucydides and Thomas Hobbes as two of their intellectual forefathers and in doing so has suggested that the core beliefs and views of these two political thinkers can be classified as Realism. This essay will set out to identify and discuss the main principles of political realism in order to, then, be able to compare and contrast the assumptions of Thucydides and Hobbes about these issues. This will be done through a brief recourse to the core realist principles and then the discussion will move on to compare the views of Hobbes and Thucydides on the topics of the international system; the state and the individual in international relations and finally the causes and justifications of war.

Political Realism sees international relations mainly as a struggle of self-interested, sovereign states that are involved in a game of power-politics within a permanent state of anarchy. The international system, according to this school of thought, is a moral- and value-free environment in which the state is seen as a rational and unitary actor that finds itself in constant conflict with the other states of the system due to the lack of an overarching world government. Stemming from their pessimistic view on human nature, the only way to achieve security in the international system, according to political realism, is by creating a Balance of Power among the most powerful states of the system.

In the writings of Thucydides, many of these core realist assumptions can be found. Pointing towards the concept of power politics, in History of the Peloponnesian War one of his main arguments is, that the strong should rule the weak, as they have the power to do so. He also picks up on themes such as the Security Dilemma, the Balance of Power and the place of justice and morality in international relations. However, to what extent he agrees or disagrees with political realism on these issues will be shown later. Thomas Hobbes, especially in his Leviathan, refers to similar concepts. His idea about the ‘State of Nature’ incorporates some of the main realist principles, such as the state of anarchy. But, here again, the limitations he makes to each of these assumptions have to be carefully considered and taken into account when comparing and contrasting his views on political realism with those of Thucydides.

As briefly mentioned earlier, both political thinkers pick up on the realist view of the international system as a value- and moral-free place of anarchy, where states live under a constant fear of attack or betrayal by others and thus are facing a Security Dilemma. Thucydides, taking up the issue of anarchy within the international system, very much agrees with the realist point of view, saying that in a system where there is no overarching authority, the only way to maintain order is through some form of Balance of Power, which – in the case of Thucydides – takes the form of the strong exercising their power over the weak. Hobbes, in comparison, takes quite a different look at this. Stemming from his theory about the ‘State of Nature’, he admits that without a world government, the system is subject to a state of anarchy and of “a war as is of every man against every man”[1]. However, Hobbes opposes the view that under such conditions it is the strong who determine the order of the international system. According to his theory of the ‘State of Nature’, every man is equal and thus “the weakest has strength enough to kill the strongest, either by secret machination or by confederacy with others that are in the same danger with himself.”[2]. The order, according to Hobbes, is rather maintained by a “general rule of reason”[3] which is that “every man ought to endeavour peace”[4] and since every man is equal in strength and desires, there is certainty that this principle will be followed as long as one’s own security is not endangered. This leads on to the realist claim of a moral- and value-free international system. According to political realism, which sees the state as the primary and simply self-interested rational actor, there can be no universal set of morals or values. Thucydides and Hobbes both don’t fully agree with that point. For Hobbes, as just pointed out, there are, what he calls “general rule[s] of reason”[5] which apply to everyone in the international system and thus create some form of moral standard which to adhere to. Thucydides is a little more sceptical of this, however, even he does not fully deny the existence of such morals and values when speaking about the Spartans’ view of the international system in his History of the Peloponnesian War (Peter J. Ahrensdorf; “Thucydides’ Realist Critique of Realism”; Polity; Volume 2, Number 2; Winter, 1997). Hence, realist assumptions about the international system can be found in the works of both, Hobbes and Thucydides, but, as has been shown, their opinions diverge from each other and from political realism on issues like order and universal morals and values in the international system. In order to understand and appreciate this difference more, it is helpful to look at the assumptions that political realism and Hobbes and Thucydides make about the individual and the state and their behaviour in international relations.

Political realism regards the state as a unitary, rational actor that is motivated by power politics and its self-interest. As far as the individual is concerned, realism holds a very pessimistic view of human nature, regarding people as power-hungry and capable of evil. Thucydides mostly shares this negative view of human nature as he sees “fear, the desire for glory, and the pursuit of self-interest”[6] as universal human characteristics, thus implying that human behaviour is uniform and predictable. Hobbes disagrees with Thucydides and political realism on this point, as although he acknowledges that humans are capable of being evil, he lays more emphasis on possible ways out of this dilemma. Hobbes argues that men have a strong and constant desire for peace and thus, they will always use their power to “obtain some future apparent Good”[7]. He also claims that peace and security in an international system without an overarching authority can only be achieved through cooperation between states and between individuals. This leads on to the next point which has to be made about the view of Hobbes and Thucydides on individuals and states: cooperation. Political realism sees no actual possibility for states to form successful alliances, as no state can be trusted since it only relies on its self-interest and does not pay much attention to what would happen to other states in the system. Thucydides takes a similar stand as he – although not ignoring the possibility – is very sceptical of the chances of success of such a form of cooperation given the anarchic structure of the international system and solely self-interested states. Hobbes, on the other hand, does recognise the limitations mentioned above, however he also says that due to the fact that all states are equal within the international system, they can “create more stable forms of coexistence among themselves”[8] and thus establish peace and security.

Moving on from the assumptions about individuals and states, the discussion will now turn to another very important concept in political realism as well as in the writings of Hobbes and Thucydides; that is war and its causes and justifications. According to political realism, war is inevitable in an international system where anarchy is the rule. As power-hungry individuals lead their states in pursuit of the national interest, fulfilment of the latter can sometimes only be achieved through conflict or the use of force. Thucydides discusses war and conflict at length in his History of the Peloponnesian War and comes to the conclusion that “What made war inevitable was the growth of Athenian power and the fear which this caused in Sparta.”[9] Here he has identified one of the main reasons for war: fear. As Thucydides sees fear as one of the universal human characteristics leading to an evil human nature and thus evil human behaviour, it can be seen that, for Thucydides, war is an inevitable feature of the international system. With the Balance of Power destabilising, which, according to Thucydides, is the only means to achieve peace, the growth of power in Athens caused the Spartans to feel more and more insecure and thus they started to prepare to defend themselves. This very much reflects the realist point of view, as it argues that without a Balance of Power there can be no peace and it also shows how easily the balance can be disrupted so that it causes a war. Hobbes’ viewpoint, again, differs from the above. In his “first and fundamental law of nature”[10] he states that the primary objective of every man “is: to seek peace and follow it.”[11] This suggests that Hobbes does not see war as a necessary means in a world of anarchy, but rather that if every man adheres to this law, there will be no need for war, as “rational sovereigns will not act in an unnecessarily aggressive manner.”[12] However, although these assumptions differ from the logic of warfare put forward by political realism and by Thucydides, the analysis of Hobbes’ view on war and conflict must not stop here. There is also in Hobbes’ Leviathan a passage where he describes circumstances under which war may be justified: “every man ought to endeavour peace, as far as he has hope of obtaining it; and when and when he cannot obtain it, that he may seek, and use, all helps, and advantages of war.”[13] Hence, this refers back to the idea of the self-interested state, as here, Hobbes seems to regard war as justified when there is no other way to achieve one’s own ultimate goal. However, Noel Malcolm argues that “[this] does not imply that such wars of aggression are inevitable – still less that they are desirable. Rather, he [Hobbes] regards them as the products of mistaken judgement about what will really serve the long-term interests of those rulers”[14] and, further, Michael Williams points out that “There is no sense in Hobbes of the glorification of war”[15]. Hence, it can be seen that, as for the topic of war, there is a common assumption found in political realism as well as in the works of Hobbes and Thucydides that war may be justified on grounds of pursuit of the national interest and in order to achieve peace at last. However, there are differences as to what is a ‘legitimate’ national interest. Where for political realism everything that is in the interest of the state and can be achieved by no other means is seen as a justification; Hobbes is far more cautious, regarding only the quest for peace as a legitimate reason to go to war. Thucydides, again, can be found in between those two extremes, as he sees the problem in human nature which causes the evil human behaviour and thus results in the outbreak of war.

Overall, it has been shown that although Thucydides and Thomas Hobbes are classed as ‘realists’, there are significant differences in a lot of their views and assumptions about international relations. Thucydides, all in all, tends to be closer to political realism in his view points than Hobbes. However, the key realist ideas about the international system, about individuals and states and regarding the causes and justifications of war can be found to a greater or lesser extent in the works of both, Hobbes and Thucydides.



1)      Boucher, David; Political Theories of International Relations: from Thucydides to the present.; Oxford University Press (1998)

2)      Brown, Chris; Nardin, Terry and Rengger, Nicholas (editors); International Relations in Political Thought; Cambridge University Press (2002)

3)      Finley, M. I. (editor); History of the Peloponnesian War. Translated [from the Greek] by Rex Warner; Penguin (1972)

4)      Hobbes, Thomas; Leviathan; Forgotten Books (20.02.2008)

5)      Keohane, Robert O. (editor); Neo-Realism and its critics; Columbia University Press (1986)

6)      Malcolm, Noel; Aspects of Hobbes; Oxford University Press (2002)


1)      Ahrensdorf, Peter J.; “Thucydides’ Realist Critique of Realism”; Polity; Volume 2, Number 2; (Winter, 1997); pp. 231-265

2)      Williams, Michael C.; “Hobbes and International Relations: A Reconsideration”; International Organization; Volume 50;  No. 2 (Spring, 1996); pp. 213-236

[1] Hobbes , Thomas; Leviathan, Chapter 13; p. 87

[2] Hobbes,  Thomas; Leviathan, Chapter 13; p. 84

[3] Hobbes, Thomas; Leviathan, Chapter 14; p. 89

[4] Hobbes, Thomas; Leviathan, Chapter 14; p. 89

[5] Hobbes, Thomas; Leviathan, Chapter 14; p. 89

[6] Boucher, David; Political Theories of International Relations; Oxford University Press (1998); p. 73

[7] cited in: Malcolm, Noel; Aspects of Hobbes; Oxford University Press (2002); p.442

[8] Williams, Michael; “Hobbes and International Relations: A Reconsideration”; International Organization;
Vol. 50, No. 2 (Spring, 1996); p. 227

[9] Thucydides; History of the Peloponnesian War; Book 1; Section 23

[10] Hobbes, Thomas; Leviathan, Chapter 14; p. 90

[11] Hobbes, Thomas; Leviathan, Chapter 14; p. 90

[12] Williams, Michael; “Hobbes and International Relations: A Reconsideration”; International Organization;
Vol. 50, No. 2 (Spring, 1996); p. 231

[13] Hobbes, Thomas; Leviathan, Chapter 14; pp. 89-90

[14] Malcolm, Noel; Aspects of Hobbes; Oxford University Press (2002); p.443

[15] Williams, Michael; “Hobbes and International Relations: A Reconsideration”; International Organization;
Vol. 50, No. 2 (Spring, 1996); p. 214


Written by: Mareike Oldemeinen
Written at: University of St Andrews
Written For: Prof Andrew Williams
Date written: 02.11.2009

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