Process philosophy (or
ontology of becoming) identifies
metaphysical reality with
change and development. Since the time of
Plato and
Aristotle, philosophers have posited true reality as "timeless", based on permanent
substances, while processes are denied or subordinated to timeless substances. If
Socrates changes, becoming sick, Socrates is still the same (the substance of Socrates being the same), and change (his sickness) only glides over his substance: change is accidental, whereas the substance is essential. Therefore, classic
ontology denies any full reality to change, which is conceived as only accidental and not essential. This classical ontology is what made knowledge and a
theory of knowledge possible, as it was thought that a science of something in becoming was an impossible feat to achieve.