ABSTRACT
In this chapter I explore the reasons why biologists have not been as successful as physicists in developing unifying, predictive, explanatory theory. Although most biologists claim that the failure results from the greater complexity of biological systems, I believe the failure is a result of most biologists being diversifiers, exploring the details of biology by observation and experiment, and of most theoretical biologists thinking inductively, whereas theoretical physicists often think deductively. After reviewing the diversifier, inductive unifier, and deductive unifier approaches to science, as exemplified by the development of our understanding of planetary motion, I compare two general explanation's accounting for the evolution of clutch size in birds—Lack's hypothesis and Murray's hypothetico-deductive theory.
