Noticing differences greatly assists survival… up the point of diminishing returns, especially for a thinking animal like us. Blindly validating perceptions of difference ultimately leads to anxiety of some sort.
Nevertheless, discerning differences would seldom become so worrisome for our hunter-gatherer ancestors. Civilization, by taming the wilderness, removes the natural stresses that would otherwise counterbalance cognitive stresses. Before we know it, we become neurotic nitpickers in one way or another.
Chapter 56 hints at how to mitigate the ‘difference bias’ that can swamp cognition so easily now: Block the openings; Shut the doors. Blunt the sharpness; Untangle the knots; Soften the glare; Let your wheels move only along old ruts. This is known as mysterious sameness.
It helps to know where one is on the bell curve of balanced awareness, i.e. not too much focus on differences or similarities. As with maintaining physical balance, noticing when we near the tipping point is crucial. As they say, ‘A stitch in time saves nine’. That ‘stitch in time’ means watching the mind as circumspectly as possible. Most notable is the tendancy to focus excessively on differences, seldom on similarities. I assume that is because noticing difference is the greater survival asset for life in general.
Much of the difficulty lies in what we think we need. Desire (need + thought) pulls perception to gloss over differences at times, and yet make mountains out of molehills of difference at other times. We habitually think what we need to think. No wonder chapter 71 warns us that thinking that one knows will lead to difficulty. Look out for examples of this continually. As chapter 71 ends, It is by being alive to difficulty that one can avoid it. The sage meets with no difficulty. It is because he is alive to it that he meets with no difficulty.