Aristotle and the search of a rational framework for biology

Chance and necessity are mainstays of explanation in current biology, dominated by the neo-Darwinian outlook, a blend of the theory of evolution by natural selection with the basic tenets of population genetics. In such a framework the form of living organisms is somehow a side effect of highly contingent, historical accidents. Thus, at a difference of other sciences, biology apparently lacks theoretical principles that in a law-like fashion may explain the emergence and persistence of the characteristic forms of living organisms that paradoxically, given the current importance attributed to chance, can be grouped into organized structural typologies. Nevertheless, the present essay shows that since its origins in Aristotelian natural history, biology aimed at achieving rational, non-accidental, explanations for the wide variety of living forms endowed with characteristic behaviors that constitute the landscape of biological species.