2.1. What is Ontology?
Ontology is, with metaphysics - leaving aside the problem of their distinction - the branch of philosophy that strives to answer the most general and universal question about the world: What there is? The question thus expressed fully corresponds to the etymological meaning of the term “ontology”: reasoned discourse (logos) on what is there (on).
The problem of what counts as an entity is “the” main problem for most philosophers throughout history, from Plato and Aristotle to our days (just think of recent formal ontology, and of mereology) and, as usual, the answers strictly depend on the conditions of validity established in the premises. The distinction between “revisionary” and “descriptive” metaphysics introduced by P.F. Strawson (1959, pp. 9-12) can be used to make clear this point. Ontologies have two main basic attitudes towards human experience; either they recognize an ontological status to whatever comes into human experience, and in this sense they are “descriptive” ontologies, or they can be “revisionary”, as long as they establish criteria for accepting – and excluding – some piece of experience in - and from - the domain of entities. Descartes and Quine are representatives of the revisionary attitude, while Aristotle is the most ancient and authoritative exponent of the descriptive approach. Leaving to the historians the interesting question of tracking back philosophical genealogies, it is evident even at a first glimpse that systemic thinking belongs to the Aristotelian “descriptive” group, in that it forges instruments of comprehension of “what there is”, without excluding other alternative or complementary criteria (on this delicate point I will be more precise further on).
The conceptual analogies among Aristotelian and systemic ontology are deeper than just being both “descriptive”, and it is worthwhile to track their similarities not for the sake of ennobling the genealogy of systemic thinking, but because systemic thinking shares the basic attitude of the ancient thinker towards human experience: the world, including ourselves, has a sound rational structure traceable in every aspect, object and detail of what there is, that becomes attainable to human comprehension using multiple methods of inquiry.