But more important than the source are the
consequenceso f that conceptiono f causesi n morala nd political
philosophy, for the same four causes operate in Aristotle's treatment
of physics, but with this differencet, hat powersa re determined
uniquely to ends in natural things and natural change,
while moral actions are determined by habits which involve
choice, and political associations and combinations are determined
at least in part by men's conception of the good. The numerous
acceptable analogies between physics, on the one hand,
and ethics and politics, on the other, have frequently tempted
philosophers to deny these differences. In the philosophy of
Aristotle, however, they mark the crucial point at which practical
sciences are distinguished from theoretical-as the analogies
between physics and politics mark the difference between
the practical sciences and the arts-for the indeterminacy of habit and choice which stands between human powers and actions make necessary in politics and ethics a dialectical method
which unites the subject matters of the two practical sciences in
contrast to the scientifically discriminated subjects treated by
scientific methods in the physical sciences.