|An 1871 caricature of Darwin|
published in The Hornet, a satirical magazine
According to Lennox, Darwin was acquainted with the concept of teleology, and while at Cambridge, he admired the argument from design in Paley’s work. Lennox says that Darwin was “apparently ready to accept creation by design as the most reasonable explanation for adaptation when the Beagle sailed. Less than ten years later he was confident of the main outlines of a theory which explained adaptation, and the creation of new species, by references to natural causes, and was an avowed agnostic.”
In his article, Lennox looks at Darwin’s two explanations of adaptations. The first explanation of adaptation is of the species of Primula which have been observed to be adopting a particular strategy, by means of particular structures. The second explanation of adaptation is of Orchids about which Darwin has commented in his Various Contrivances.
In his conclusion to the article, Lennox provides a summary of his key arguments:
By carefully examining Darwin's actual use of teleological explanation, one finds an explanatory structure which is at once irreducibly teleological, and at the same time unlike any of the standard forms of teleology in the nineteenth century. Indeed it is only rather recently that there is a model of teleological explanation to which Darwin's reasoning conforms. Moreover, though Darwin occasionally endorses his own teleology, to my knowledge he never provides a philosophical commentary on it.
This last fact is closely related to the puzzle of Darwin's public silence on how he intends his readers to understand his use of terms such as 'Final Cause', 'purpose', 'end for which', 'good for which'. After all, his letters and notebooks indicate that he thought about it a good deal. Puzzling as this is, however, it is not a special puzzle about his teleology. The same sources show that he thought deeply about the nature of inductive support for theories, but his published books and papers leave such issues alone. Darwin read and thought much on the philosophy of biology — he published nothing at all on the subject. There is no reason to think he would deal with the question of final causation any differently. A skilled rhetorician knows when to speak, but more importantly, when to be silent. That followers as different as T.H. Huxley and Asa Gray could both find a teleology that they could live with in Darwin's explanatory practice indicates that, as usual, Darwin was a skilled rhetorician.Lennox notes that while Darwin’s explanatory practices are not in line with the dominant philosophical justifications of teleology at his time, they are in conformity with the recent defenses of the teleological character of selection explanation.