FEW HEROES LOWER their sights in the prime of their lives; triumph leads inexorably on, often to destruction. Alexander wept because he had no new worlds to conquer; Napoleon, overextended, sealed his doom in the depth of a Russian winter. But Charles Darwin did not follow the Origin of Species (1859) with a general defense of natural selection or with its evident extension to human evolution (he waited until 1871 to publish The Descent of Man). Instead, he wrote his most (...) obscure work, a book entitled: On the Various Contrivances by Which British and Foreign Orchids Are Fertilized by Insects (1862). (shrink)

The diversity, complexity and adaptation of the biological realm is evident. Until Darwin, the best explanation for these three features of the biological was the conclusion of the “argument from design.” Darwin's theory of natural selection provides an explanation of all three of these features of the biological realm without adverting to some mysterious designing entity. But this explanation's success turns on the meaning of its central explanatory concept, ‘fitness’. Moreover, since Darwinian theory provides the resources for a purely causal (...) account of teleology, wherever it is manifested, its reliance on the concept of ‘fitness’ makes it imperative that conceptual problems threatening the explanatory legitimacy of this notion be solved. (shrink)

The diversity, complexity and adaptation of the biological realm is evident. Until Darwin, the best explanation for these three features of the biological was the conclusion of the “argument from design.” Darwin's theory of natural selection provides an explanation of all three of these features of the biological realm without adverting to some mysterious designing entity. But this explanation's success turns on the meaning of its central explanatory concept, ‘fitness’. Moreover, since Darwinian theory provides the resources for a purely causal (...) account of teleology, wherever it is manifested, its reliance on the concept of ‘fitness’ makes it imperative that conceptual problems threatening the explanatory legitimacy of this notion be solved. (shrink)

In several places we have argued that ‘fitness’ is a primitive term with respect to the theory of evolution properly understood. These arguments have relied heavily on the axiomatization of the theory provided by one of us. In contrast, both John Beatty and Robert Brandon have separately argued for a “propensity“ interpretation of “fitness” ; and in Brandon and Beatty they attack our view that “fitness“ is a primitive term in evolutionary theory, concluding that a definition by way of propensities (...) is possible and preferable. Here we reply to their criticisms, and argue that, at most, the view that fitness is a statistical propensity is a terminological variant on our thesis that it is a primitive in evolutionary theory. (shrink)