In the works of Socrates' disciple Plato (428-347 B.C.) and in those of Plato's disciple Aristotle (384-322 B.C.), abundant justice is done to these fields of human activity.

These two, the greatest among the Greek philosophers, differ from each other in many things, but it is worthy of remark that they both seem to regard the whole sphere of human knowledge as their province.
Plato is much more interested in the moral sciences than in the physical, but he, nevertheless, feels called upon to give an account of how the world was made and out of what sort of elements.

He evidently does not take his own account very seriously, and recognizes that he is on uncertain ground.

But he does not consider the matter beyond his jurisdiction.
As for Aristotle, that wonderful man seems to have found it possible to represent worthily every science known to his time, and to have marked out several new fields for his successors to cultivate.

His philosophy covers physics, cosmology, zooelogy, logic, metaphysics, ethics, psychology, politics and economics, rhetoric and poetics.
Thus we see that the task of the philosopher was much the same at the period of the highest development of the Greek philosophy that it had been earlier.