TIPwhere he argued that the theory is so broad-brushed that it cannot even identify
the most important structural change that has taken place in international politics over
the past thousand years: when Medieval Europe gave way to the modern state
system.^3 Although it is true that Waltz adopts a very parsimonious approach to
theory-building in order to extend the reach of his theory we argue that, paradoxi-
cally, as a consequence of the conditions he lays down, the theory simply cannot be
applied to substantial areas of the macro-historical canvas. To the counter-argument
that anomalies can be found for all highly general theories, we say that the anomalies
revealed by a world historical perspective are so large as to undermine the theory’s
claim to universality: it simply doesn’t work for huge swathes of time and place.
What we do in this chapter, therefore, is to show why this paradox occurs and
how other theorists have endeavoured to highlight and accommodate the complexity
and variation in international politics. We do so through the lens provided by the
main components of Waltz’s theory: units, system, structure and process. Then in a
final section we examine the implications of Waltz’s theory for the periodization of
world history and show that the periodizations developed by theorists who adopt a
less parsimonious approach to theory-building can more effectively accommodate
the variation and evolution that has occurred in international politics across the course
of world history. We end by suggesting that despite its universalist aspirations, Waltz’s
theory provides an inadequate framework for looking at world history, but that the
theory can and is proving very useful to world historians who are examining more
specific periods when the conditions that he lays down apply.
Units
At the heart of Waltz’s theory is the notion of ‘like units’. The reference to the term
‘units’ is deliberate because Waltz acknowledges that the nature of the units that
operate under conditions of anarchy can take many different forms. He distinguishes
between city states, empires and nations, and as already noted, considers that his
theory can be extended to tribes, firms and street gangs.^4 It is because these units
are so very different that it is not possible to account for the unchanging texture of
international politics in terms of their internal characteristics. The parsimonious
decision to exclude the internal characteristics of the units from theoretical
consideration is essentially dictated by the theory’s terms of reference. Waltz wants
to account for the persistence of anarchy and this cannot be done by making
reference to the internal characteristics of the units that constitute the anarchy
because they have self-evidently varied so dramatically across time. However, Waltz
takes the argument one step further by suggesting that, at any particular point of
time, if an internal development within a unit gives it a power advantage over the
other units, then there will be a tendency for this development to be emulated by
these other units, although he is quick to qualify the more profound implication of
this position by insisting that the theory does not lead one to expect that emulation
‘will proceed to the point where competitors become identical’.^5 But in what sense,
then, are these units ‘like units’? Waltz argues that they are ‘like’ units in the sense
The paradox of parsimony 289