the mean relative to us...

the mean relative to us, this being determined by a rational principle, and by that principle by which the man of practical wisdom [ phronimos ] would determine it.’[^33] Virtue, therefore, is a habit or disposition to choosing the right medium between excess and shortage. But this is not easy, for the right means is not the arithmetic mean. To find it we need another rule. This rule will be the one established by the prudent man and applied just as he would apply it.

In short, we cannot determine what is or is not virtuous without the concurrence of the prudent man. The mid point is dictated by reason or by the straight rule of the prudent man. This reason or straight rule is, rather, correct reason, that is corrected reason.

It is the limit to which a process of correction tends, one of elimination of errors, by relation to the end sought: ‘[...] there is a mark to which the man who has the rule looks, and heightens or relaxes his activity accordingly, and there is a standard which determines the mean states which we say are intermediate between excess and defect, being in accordance with the right rule ( katà tòn orthòn lógon )’[^34] .

Therefore, prudence requires experience: ‘Young men become geometricians and mathematicians and wise in matters like these, it is thought that a young man of practical wisdom cannot be found.

The cause is that such wisdom is concerned not only with universals but with particulars, which become familiar from experience.’[^35] Experience is time and memory, but not just any lapse of time, but one which one has spent reflecting, trying to understand the nature of the things we see, of the actions we do and what happens to us. Experience is the memory of a time lived and thought, for it is the fruit of succeeding corrections.

But let us remember that prudence itself is a virtue and, moreover, ‘it is impossible to be practically wise [ phronimos ] without being good’[^36] . Therefore, nobody could be prudent without following the ruled dictated by prudence. Nobody could be prudent without having been already. This vicious circle (or virtuous one, depending on how we look on it) is resolved by education and action, that is, by action steered by somebody prudent until one becomes prudent oneself[^37] .

The prudence of an experienced person serves for drawing up rules, ‘since the universals are reached from the particulars’[^38] .