ABSTRACT
According to Plato the forms physical matter takes on exist on their own account outside
matter as actual objects of understanding called Ideas…But according to Aristotle the
forms of physical things exist only in matter and not as actually understandable. Since we
can only understand what is actually understandable…our minds need to make things
actually understandable by abstracting their forms from their material conditions. Our
7.1 ‘SIGHT IS THE PRINCIPAL SOURCE OF KNOWLEDGE’
Bertrand Russell says of Aristotle that his metaphysics ‘may be described as Plato diluted
by common sense. He is difficult because Plato and common sense do not mix easily’2 Born at
Stagira on the northern shores of the Aegean in 384 BC, Aristotle spent two important periods
of his life in Athens and in the proximity of Plato and the Academy. For twenty years, from 367
until Plato’s death in 347, he was first a student and then a teacher and independent researcher at
the Academy. Returning to Athens in 335, he taught at his own rival school, the Lyceum, until
twelve years later, having been indicted like Socrates for impiety, he fled to Chalcis in order not
to suffer the same fate. He died the following year, in 322 BC. Inevitably, therefore, his name is
linked with that of Plato, as the two giants of ancient Greek-and all European-philoso-
phy, and his thought tends first of all to be compared or contrasted with that of his teacher.
