The four clauses that close this chapter are among the most precisely constructed in the book, and each has the same shape: a quality is affirmed, and the harm normally inseparable from it is removed.
Square without cutting. A square edge is what makes a corner sharp; the sage has the definiteness and not the wound. Sharp without piercing. Straight without stretching, which is to say upright without pulling anything into line. Bright without dazzling, which is illumination that does not blind the person it falls on.
The list is a direct answer to the problem the middle of the chapter raised. If the straight turns strange and the good turns monstrous, then the danger in any quality is its own excess, and the reversal the chapter describes is what happens when a quality is carried to the point where it damages. What is recommended is not the abandonment of the qualities but the removal of their edges.
That distinguishes this passage from a simple counsel of moderation. Nothing here is diluted. The sage is square, sharp, straight and bright, all four, and the four things subtracted are effects on other people rather than degrees of the quality itself.
The pattern echoes elsewhere in the book. Chapter twenty-eight says that the greatest cutting does not divide. Chapter forty-five says great straightness seems bent. Chapter fifty-eight is the version that is neither a paradox nor an appearance: the qualities are real, they are held at full strength, and their capacity to harm has been taken out of them.