   Whatever the position on whether constraints count as causes, the lesson to be taken from this part of the adaptationism debate is that it is essential to precisely specify the rival evolutionary hypotheses. There are many examples of such precise specification in the biological literature. For example, Frank (1985) and Stubblefield and Seger (1990) analyzed the influence on sex ratio optima of different constraints on the information available to parents; Lloyd (2005) described the evidentiary support for explanations of the evolution of the female orgasm. Lloyd's analysis supports Symons' (1979) proposal that the female orgasm exists because of a developmental constraint in combination with strong selection for the male orgasm. If males fail to achieve orgasm then no reproduction occurs. The tissue responsible for the male orgasm appears early in human development, long before sexual dimorphism occurs, and this tissue is found in both male and female sexual organs. This example contains competing hypotheses that have commitments about boundaries and about natural selection. The Symons constraint explanation invokes a feature of development and indirect selection on a different trait, whereas the adaptive hypothesis does not incorporate the developmental constraint and instead, posits a direct role for selection.