Epistemology of living organisms in Aristotle's philosophy

For Aristotle, living entities are exemplars of substance being. This means that they show a unity of matter and form on the one hand and of potency and act on the other, in contrast to the duality shown in these respects by accidental beings, exemplified by artefacts. An animal, although composed of the same elements (arche) considered by presocratic philosophers, is defined as an individual unity generated and maintained by an organisation which relates its parts in a hierarchical and functional way. Crucial to his understanding of the living is the hierarchy in which each part is defined by fitness to a function, as an instrument (organon), performing within the whole. The whole being is also an instrument tan organism) for a specific kind of life, which actualises an internal and specific principle (psuche). Both the regularity of appearance of each organism and its fitness to a specific function justify the introduction, in addition to the study of necessary causes, of an additional way of analysis in terms of hypothetical necessities, or necessary conditions for a goal to be attained. Fitness to a function and regularity of appearance make necessary the analysis nor just of the elementary components, but of another principle (eidos, form) which defines a structure directed to a goal. While for accidental brings matter can survive their destruction, the corruption (pthora) of living entities causes the disruption of the entire unity of matter and form ana form. Living entities, both as matter and form, show therefore a temporal limitation in being generated and corrupted, although they persist as specific forms since they generate offspring which regularly share their differential characteristics defined in their form. After reviewing recent interpretations of Aristotle's biological writings, I will suggest the usefulness of this conceptual framework to analyse some problems approached by current developmental biology.