Homology thinking reconciles the conceptual conflict between typological and population thinking

Abstract

This paper attempts to reconcile the conceptual conflict between typological and population thinking to provide a philosophical foundation for extended evolutionary synthesis (EES). Typological thinking has been considered a pre-Darwinian, essentialist dogma incompatible with population thinking, which is the core notion of Darwinism. More recent philosophical and historical studies suggest that a non-essentialist form of typology (i.e., representational typology) has some advantages in the study of evolutionary biology. However, even if we adopt such an epistemological interpretation of typological thinking, there still remains an epistemological and methodological conflict between these two styles of thinking. How can we relate typological thinking with population thinking in pursuit of more integrated or interconnected research into evolutionary biology? I propose that homology thinking, which is another style of thinking that recognizes homologous characters, provides a common basis for typological representations of character states and for character dynamics in an evolving population. Good examples of this bridging role are found in teratology and breeding, where variation and novelty are recognized in developmental and morphological traits, gene expression patterns, and so on. Essentialism-free, dynamic views of homology have great potential to reconcile typological and population thinking and to set the stage for the EES.