The five colours blind the eye.
The five tones deafen the ear.
The five flavours dull the taste.
Racing and hunting madden the mind.
Precious things lead one astray.
Therefore the sage is guided by what he feels and not by what he sees.
He lets go of that and chooses this.
 Most other texts (as we saw yesterday with Cheng) translate this more literally as being '... for the belly and not for the eye'.
The Ma wang tui text also adds '... in the government of the sage...', a variant which does not come up in any of the later versions.
Wang's commentary say that '...to use things to provide for the belly is to nourish oneself. To use things to provide for the eye is to enslave oneself...' and states that the sage accepts the former and rejects the latter.
Cheng disagrees vehemently. As a practitioner of Taoist yoga, he says:
The one seems substantial, but is, in fact, hollow; the other seems hollow, but is, in fact, real. This is the same as saying that although, seemingly, the abdomen is supposed to be filled with substance, on the contrary one should fill it with breath (ch'i); although the valley seems to be empty, it is, in fact, filled with vapour (ch'i ). By the same token it might seem that the eyes should be used for looking, but in fact one should use them only to see inwardly... This is what Lao-tze means when he speaks of the 'Tao of the Sage'. Wang Pi's interpretation is that only one's belly is for filling with food, but this is tantamount to suggesting that one pluck out one's eyes. If that were so, why would Lao-tze say, 'that which is there is an advantage, but it is its emptiness that makes it useful'?
I think Feng's translation of the last line as a stroke of absolute genius. The sage 'lets go of that'... all that... and 'chooses this'... What is closer than 'this'?
The Chandogya Upanishad has the famed statement TAT TVAM ASI - 'Thou art That', but 'that' is definitely - both in English and in Sanskrit (and in all other tongues I can think of) - 'something else' and 'some other thing over there'. Only 'this' is 'here'.
This doesn't mean to say that it can't be an object - this computer, this room - but that is not the 'this' that Lao-tze is talking about. The 'this' he means is this thing here that's writing or reading this. This - the lucid and present awareness of the instant as it passes.
One of the practices used by late Ch'an and Zen is what's called the hua t'ou - 'the head of a thought'... A technique for getting into it is to continuously question yourself as to who this is... Who is this that's reciting the Buddha's name?', 'Who is this that's dragging this corpse aroound here?', 'Who is this that's reading this?... saying this?... thinking this?... aware of this?...' The object being to get to a point where your ordinary relative mind relinquishes its hold and you can step into the mind that is beyond the cage of conceptual 'on-offs' (to use a binary term).
'The stillness in stillness is not real stillness; stillness in motion is stillness indeed!'
Feng's translation (echoing the Ma wang tui text) hits exactly that point, thereby rendering the scruples of both Wang and Cheng superfluous. You leave 'that'; you choose 'this'.
As ever, screeds more could be said... This is enough, no?