disadvantage. Punctuated models go further to claim that any prediction is inherently
impossible, given the unexpected nature of exogenous shocks and the chaotic echoes they
create in systems. Furthermore, to demonstrate that the political change observed is
indeed radical and significant, one must arrive at a clearer definition of what counts as a
constitutive change. This is a problem that biologists encounter consistently in
determining what changes constitute speciation, as opposed to variation within a species.
Kuhn encountered a similar difficulty in separating those scientific innovations that
contributed to "normal science" from those that launched a paradigm shift. To solve this
difficulty, paleontologists have defined a species as the highest order within which
breeding can take place. Kuhn, similarly, indicates that meaningful communication is
only possible within any paradigm. Goertz, Diehl and Cioffi-Revilla have addressed this
difficulty by explaining their choice of the rivalry as unit of analysis in terms of a
punctuated equilibrium logic. As the authors cited above have shown, constitutive
change can mean change of the international system, change of constitutive elements
defining a relationship between two states, change in the policies defining the identity of
an empire or state or changes that radically redefine the meaning of a situation, such as a
rivalry or a dispute.
We do not know, as yet, how common such changes are in international affairs.
As in paleontology, the adoption of a punctuated model makes change appear where
previously, due to lack of data, stasis was assumed. The adoption of a punctuated model
in political science can thus enhance our ability to accept the existence of sudden and
significant changes, understand the underlying causes and mechanisms and explain the
ensuing effects. A more detailed application of the biological variant of the punctuated
equilibrium model to political science could shed light on the types of ideas that succeed
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Convention