As to thy body, it is good to use discretion in eating, drinking and sleeping, and in all manner of bodily penance, and in long vocal prayer, and in all bodily and sensible feelings and fervours, or earnestness of devotions, and tears and the like, and in discoursing with the imagination in times of aridities and want of the feeling of grace. In all these works it is good to use discretion, for the mean is the best.(John Climacus)

This is Aristotle's mean, of course, not the "Sally is mean to her brother" kind of mean.

In the Nichomachean Ethics Aristotle writes,

Now, if we have any quantity, whether continuous or discrete, it is possible to take either a larger (or too large), or a smaller (or too small), or an equal (or fair) amount, and that either absolutely or relatively to our own needs. y an equal or fair amount I understand a mean amount, or one that lies between excess and deficiency.

But Aristotle offers a vision of the mean far beyond that of the body. He also writes,

Virtue, then, is a habit or trained faculty of choice, the characteristic of which lies in moderation or observance of the mean relative to the persons concerned, as determined by reason, i.e. by the reason by which the prudent man would determine it. And it is a moderation, firstly, inasmuch as it comes in the middle or mean between two vices, one on the side of excess, the other on the side of defect; and, secondly, inasmuch as, while these vices fall short of or exceed the due measure in feeling and in action, it finds and chooses the mean, middling, or moderate amount. Regarded in its essence, therefore, or according to the definition of its nature, virtue is a moderation or middle state, but viewed in its relation to what is best and right it is the extreme of perfection. . . .

In seeking spiritual perfection, John does not encourage such moderation.