Causality and Finality in Theoretical Biology: A Possible Picture

In this article we describe a necessary condition for science to develop a theoretical side. It lies in the ability to expand a set of empirically observed facts into a larger set of “imaginary” events or virtual facts. No science lacking this extension can be said to be “theoretical.” Theoretical biology will exist only insofar as biologists are able to construe a set of theoretical developments generated according to a constructive definition, and to specify how reality propagates among this set of virtual processes. (Such is the case of classical Hamiltonian mechanics, where initial data generate reality inside the set of trajectories describing virtual motion.) That the consideration of virtuality is necessary to science was clearly perceived by Aristotle, who systematized it with the distinction between potentiality and actuality. We show how a set of virtualities might be defined to classify the Bauplane of animal organisms, by referring them to three basic spatial axes. And we briefly refer to Aristotle’s theory of four causes to explain how efficient and final causes may be subsumed under formal causality (using the notion of “morphogenetic field”). A text from Aristotle’s Politico particularly illustrative of his general method is given in an appendix.