The Mean

The mean — the central and correct — is the structural virtue of the Book of Changes. In each hexagram the second and fifth lines occupy the "central" places of the lower and upper trigrams, and a line that is both central and in its proper place is the most favored of all: it holds the middle without excess or deficiency. The commentaries return again and again to whether a line is "central," "central and correct," or has strayed from the middle.

The idea is ethical as much as diagrammatic. To hold to the mean is to keep the balanced, measured course that neither overreaches nor falls short — the disposition that lets a ruler govern from the fifth place and an official serve rightly from the second. It is close kin to modesty and to timeliness: the middle way is the way that stays in accord with the time and avoids the ruin of extremes.