“A young man is not a fit person to attend lectures on political science, because he is not versed in the practical business of life from which politics draws its premises and subject-matter. Besides, he tends to follow his feelings, with the result that he will make no headway and derive no benefit from his course, since the object of it is not knowledge but action. It makes no difference whether he is young in age or youthful in character; the defect is due not to lack of years but to living, and pursuing one’s various aims, under sway of the feelings; for to people like this knowledge becomes as unprofitable as it is for the incontinent.” 
We should greatly enlarge the entrances to all the departments of political science in the land, not so as to admit more students, but so as to fit those words in large letters on the lintels.
 Aristotle, The Nicomachean Ethics, I.iii:1095a, tr, J.A.K. Thomson (London: Penguin Books, 2004), p.6; capitalisation added to first letter.