DIVERSITY VERSUS COMMONALITY: STARTING WITH GENES

The adaptation-versus-constraint debates that began in the late 1970s were a part of a larger and more diffuse critique of the Evolutionary Synthesis. Mainstream neo-Darwinism was subject to a very wide range of methodological criticisms in those days, including the alleged unfalsifiability of adaptationism, the failure to consider nonselective evolutionary phenomena such as drift, and the inability to explain punctuation in the fossil record. The debate was also influenced by political factors, such as the association of adaptationist theorizing with status quo conservative politics (an association at least as old as the British natural theologians; see Desmond 1989). The arguments discussed in the following paragraphs are products of these debates. My own sympathy with the constraint side of these debates is already obvious to the reader. However, it would certainly be a mistake to accept at face value these critics' accounts of the shortcomings of Synthesis theory. We are searching for the genuine theoretical grounds for conflict between structuralist and adaptationist theories, and those grounds were often misstated in those debates. For that reason, this section examines a topic that preceded the constraints debates and that does not directly involve development at all. It exposes the incorrectness of at least one of the early criticisms of the Synthesis, but it also reveals a methodological tendency in Synthesis thought. The tendency was innocuous at first, but it played a contentious role in the later Synthesis stance against the importance of development.