Generalization in Evo-Devo

How general are our findings concerning the evolution and development of life forms? I will discuss this question of generality and the related question concerning the existence of lawlike generalizations with specific reference to evolutionary developmental biology (evo-devo). On the one hand, evo-devo suggests that the evolution and development of life forms is more contingent than we have previously presumed, thus showing that we have accidental and non-generalizable results concerning evolutionary and developmental phenomena. On the other hand, evo-devo reveals the existence of generality-maintaining mechanisms, thus showing that certain evolutionary and developmental generalizations have stability and necessity. These two findings suggest a picture of evolution as being both stable and contingent, repeatable and unique, and generalizable and non-generalizable. This picture of evolution was already present during the Modern Synthesis. At the same time, evo-devo has provided us with new insights into what are generality-destroying, generality-maintaining, and generality-creating mechanisms behind the evolution and development of life forms.