Three Glimpses of Evolution

Have we yet recognized the full complexity of evolution? Indeed, can we ever expect to do so? The aim of this chapter is to discuss the extent to which our methods for studying evolution may limit our perceptions of it and to consider whether any approach is capable of encompassing all the issues. The chapter focuses on an aspect of method which is particularly hard to stand back from. This is the area, beyond data gathering and experimental techniques as such, of relating the diversity of available data and inferring their meaning in relation to a full understanding of evolution: what one could call the tacit rationale, since the underlying arguments and assumptions are so rarely made explicit. Three such rationales are identified and characterized and then, in a final section, assessed in the light of their contribution to a possible single, coherent approach to evolution. The vertebrate eye is used to illustrate the arguments, for reasons that will become evident.