Waltz’s discussion of human nature is rather nuanced and his use of the traditional
image of human nature is subtle. In Man, the State and War, Waltz reviews assump-
tions about human nature that are commonly held by ‘optimists’ and ‘pessimists’.
Waltz concludes his consideration of the ‘first image’ by essentially arguing that we
don’t need to take a position on those assumptions.^11 Our human natures, he argues,
are the same in times of war and in times of peace: ‘the importance of human nature
as a factor in causal analysis of social events is reduced by the fact that the same
nature, however defined, has to explain an infinite variety of social events’.^12 If
human nature is constant, and history is variable, then human nature cannot explain
the variation:
Human nature may in some sense have been the cause of war in 1914, but by
the same token it was the cause of peace in 1910. In the intervening years
many things changed, but human nature did not. Human nature is a cause
only in the sense that if men were somehow entirely different, they would
not need political control at all.^13In Theory of International Politics, Waltz argues that to focus on unit level causes is
to be ‘reductionist’.^14 Moreover, Waltz is careful to say in Man, the State and War,
that the ‘human nature we do know reflects both man’s nature and the influence of
his environment’ and he emphasizes the ‘error involved in taking the social man as
the natural man.’^15
Yet, though Waltz argues clearly that it is not necessary to take a view of
human nature to understand world politics, he does take one. I argue that Waltz’s
assumptions essentially amount to traditional realist assumptions. Specifically, in
Man, the State and Warand Theory of International Politics, Waltz’s implicit assumptions
about human nature – that our human natures are fixed, that we can’t trust others,
and that decision-makers are rational calculators who seek to promote their narrowly
defined self-interests – are consequential for theorizing from a structural realist
perspective. Thus, human nature, for Waltz, determines world politics as much or
more than the anarchic structure of world politics.
How does Waltz take a view of human nature, even though he discounts the
importance of human nature in explaining world political outcomes? First, he
implies a fixed human nature. ‘The assumption of a fixed human nature, in terms
of which all else must be understood, itself helps to shift attention awayfrom human
nature – because human nature, by the terms of the assumption, cannot be changed,
whereas social-political institutions can be.’^16
More important is the content of this ‘fixed’ nature. In his interpretation of
Rousseau’s stag hunt, Waltz characterizes anarchy not simply as a context of uncer-
tainty, but of distrust. He says, ‘In cooperative action, even where all agree on the
goal and have equal interest in the project, one cannot rely on others.’^17 Moreover,
conflict is inevitable, in Waltz’s view. He argues that ‘Force is the means of achieving
the external ends of states because there exists no consistent, reliable process of
reconciling the conflicts of interest that inevitablyarise among similar units in a
160 Rethinking ‘man’