‘The word samadhi carries within itself two absolutely contrary meanings: “perfect reception” and “perfect non-reception.” In order to “perfectly receive” each instant as it occurs, it is necessary to “perfectly not-receive” the previous instant and the future instant. No matter how accurately and in what detail a mirror may reflect what is before it in one instant, should it be turned to face a new direction, the previous reflection will disappear without a trace and the mirror will faithfully reflect what is newly before it. Likewise, in its power to always perfectly receive what is at hand and to perfectly not-receive what is not at hand, the heart functions doubly. For this reason, from times of old, the heart has been likened to a mirror. The state in which this power functions to receive everything perfectly, just as it is – that is to say, the heart of perfect nonreception that does not get caught up – is called “the heart that is still,” or simply Zen.’ (Novice To Master)
Two things strike me about this passage: the first is the use of the word heart, rather than mind. We often invoke ‘luminous mirror wisdom’ in our chanting and dedications, so he is right that the analogy is deeply ingrained in this practice – but I like how he (or the translator, given that the same character can indicate both ‘heart’ and ‘mind’ in Japanese) situates this in the heart, and not just in mental processes. Second, is the realisation of what it takes to ‘perfectly receive’ a moment – that is, how much of our usual conditioning of values and judgements we have to put aside for this to happen.