Chapter 2 argues that although the Analytic of the Teleological Power of Judgment offers an argument for the necessity of teleological judgments of organisms, Kant is ultimately interested in the conceptual purposiveness of nature as a whole. He constructs an argument from the organism to this conclusion, because it allows him to assimilate characteristic features of a dialectic, specifically the fact that it ensnares ordinary understanding. This serves the end of showing that although the principle of the purposiveness of nature is a transcendental principle of reason, employing it is free of the sort of contradictions that typically beset reason. It has a legitimate and indeed necessary role to play in experience. The chapter further argues that the discussion of the methodology of biology is of great philosophical interest. For Kant all causal explanations are mechanistic and he develops a unique model for mechanistic explanations of the processes through which organisms produce or organize themselves. Teleological judgments of organic nature are not therefore a threat to the project of the comprehensive mechanistic explanation of the natural world. The chapter demonstrates this by examining Kant’s views of contemporary theories of generation, Blumenbach, his papers on human races and his evolutionary speculation.

Chapter 4 contends with the Dialectic of the Teleological Power of Judgment and the discursivity of the understanding. It argues that a discursive understanding must think of the empirical world as ordered by an ideal system of universal concepts, which takes the form of a complete hierarchical taxonomy: from the most general empirical concepts to ever more specific concepts. It argues further that the assumption of a comprehensive hierarchy of concepts determining the sensibly given is Kant’s way of talking about the objective order of nature. Only the complete but unattainable determination of the sensibly given by a complete system of concepts can ground the claims to objectivity made in determinative judgments. Kant ultimately thinks of such a system and its concepts as not merely descriptive but as causally informative and thus explanatory as well. It is a transcendental condition of empirical experience and knowledge, which follows from the fact that we are discursive creatures in pursuit of objective knowledge. An important consequence is that empirical knowledge claims are always revisable and indeed defeasible. A further very important argument shows that the part-to-whole or mechanistic form of physical explanation is also grounded in the discursivity of our understanding.