We discussed the second programme in the BBC series “The Great Philosophers”, a series of discussions broadcast in 1987 by Bryan Magee with various eminent academics.  In this second episode, Magee and Martha Nussbaum discussed Aristotle.  Aristotle was a pupil of Plato, but he became perhaps even more of an influence through the ages than his teacher, particularly in metaphysics, science and ethics.  Unlike Plato, Aristotle did not seek knowledge from anywhere beyond the material world as experienced by sensations.  He built up his insights from experience, identifying subjects and predicating something about that subject.  Building on that, his predicate logic was the logic through into the 19th century.  He was interested in identity and what was the essence of a subject while it developed and changed.  His four causes (of a subject) were material, formal, efficient, and final.  Things are made from matter, but it is their form, brought into being and modified by the efficient cause that gives them identity.  The form is not Plato’s other-worldly pattern, but just their proper organisation or arrangement of that matter driven by the efficient cause.  He would have been fascinated by DNA!  Also important to identity is the final cause - the function or purpose of the subject.  The function of a human is to live a good life, and Aristotle set down a code of ethics to achieve the final cause.  He could interrelate and classify the world around him, and his biological classification stood for years.  Considering how little of his writing survived, the endurance of his influence on philosophy and science is remarkable.