With reference to the curious interpretation of trigrams according to their minority component (two Yangs and one Yin makes a "Yin trigram", while two Yins and one Yang makes a "Yang trigram") Ziporyn quotes the Warring States document The Great Commentary (I think), a "wing" of the Zhouyi: "Situations quantitatively dominated by receptivity or subservience [those exemplified by Yin trigrams], the responsiveness that brings things to completion, may nonetheless holistically function as active and creative [Yang], as actively initiating new existences." The point is, I think, that Yang works because Yin provides the 'space' for it to do so. Yin calls forth Yang. Thus, Yang transforms in the presence of Yin.
Keeping this in mind, we might profitably revisit that pivotal passage in the Inner Chapters of the Zhuangzi where "fasting of the heart/mind" is described as "listening with qi". Qi, we are told is "an emptiness, a waiting for the presence of beings." (4:9) (Qi can and does mean many things throughout Chinese philosophy, but we need only concern ourselves at the moment with what it means for Zhuangzi here, namely "emptiness".) And this, it seems to me, corresponds to Yin. Thus, we can say, find the Yin within.
Nearly all, if not all, of our human activity, being human, can be described as Yang. This is exercising our existence as beings, and can hardly be dismissed as unnecessary or misguided. But there is, as we all know, a hollowness, an emptiness, at the heart of us all. We require a grounding and assurances, that are not forthcoming. Rather than casting about for definitive stand-ins for these in the form of 'answers' (God, Universal Self, The Ground of Being, etc.), Zhuangzi suggests we make use of the emptiness itself. To do so, the passage goes on to tell us, is to allow the rug to be pulled out from under our most precious 'possession', or sense of being a self. It is to allow that our self "has yet to begin to exist". It's trying, but it cannot. It cannot because our Yang is embedded in Yin; it is always a becoming and is never an 'is'. Taking this onboard, living this, we wander.
The context of this passage, it is important to remember, concerns how to affect political reform. "Taking the mind as one's teacher", forging ahead as Yang, will be of little use, and may even get us killed. Reconnecting with one's inner Yin, on the other hand, allows one to follow along with the target Yang as the Yin necessary to allow it to change. Zhuangzi suggests we be qi/emptiness/Yin to the Yang we wish to see transformed, just as finding our own has transformed us. The point is to be that 'space' that invites change, not another 'being' wishing to displace another 'being'.
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