 At the end of Structure, Kuhn drew an analogy between the development of science and evolutionary biology. This was surprising, since ‘evolution’ is commonly employed as a contrast term to ‘revolution’. Kuhn’s main point was that evolution ramifies rather than progressing toward a final goal, yet its degree of specialization through speciation can be regarded as a sort of progress, a progress from a historically existing benchmark rather than a progress toward a preordained, speculative goal. So specialization is an indicator of progress. As for revolutions, they correspond to macromutations.