It is the mark of an educated mind to expect that amount of exactness which the nature of the particular subject admits. It is equally unreasonable to accept merely probable conclusions from a mathematician and to demand strict demonstration from an orator.
AristotleThe purpose of the present study is not as it is in other inquiries, the attainment of knowledge, we are not conducting this inquiry in order to know what virtue is, but in order to become good, else there would be no advantage in studying it. For that reason, it becomes necessary to examine the problem of our actions and to ask how they are to be performed. For as we have said, the actions determine what kind of characteristics are developed.
AristotleThe soul consists of two parts, one irrational and the other capable of reason. (Whether these two parts are really distinct in the sense that the parts of the body or of any other divisible whole are distinct, or whether though distinguishable in thought as two they are inseparable in reality, like the convex and concave of a curve, is a question of no importance for the matter in hand.)
Aristotle