《道德经》第十四章
视之不见，名曰夷﹔听之不闻，名曰希﹔搏之不得，名曰微。此三者不可致诘，故混而为一。
其上不皦，其下不昧。绳绳兮不可名，复归于物。
是谓无状之状，无物之象，是谓惚恍。迎之不见其首，随之不见其后。
执古之道，以御今之有。能知古始，是谓道纪。
《Tao-Te Ching》Chapter 14
We look at it，and we do not see it，and we name it‘the Equable.’We listen to it，and we do not hear it，and we name it‘the Inaudible.’We try to grasp it，and do not get hold of it，and we name it‘the Subtle.’With these three qualities，it cannot be made the subject of description；and hence we blend them together and obtain The One.
Its upper part is not bright，and its lower part is not obscure. Ceaseless in its action，it yet cannot be named，and then it again returns and becomes nothing. This is called the Form of the Formless，and the Semblance of the Invisible；this is called the Fleeting and Indeterminable.
We meet it and do not see its Front；we follow it，and do not see its Back. When we can lay hold of the Tao of old to direct the things of the present day，and are able to know it as it was of old in the beginning，this is called（unwinding）the clue of Tao.
【易解】
看它看不见，就叫"夷"；听它听不到，就叫"希"；捉它捉不着，就叫"微"。从这三方面不可以加以探究，所以是浑融无名的元始。居于其上的本源已不清楚，由它而下的现实世界是清晰具体的。它本身渺渺茫茫，无以名状，不同于现实的具体存在。这就叫做没有确定形状的形状，不可归结于具体组分的显象，它是不确定性的表征。围绕着它团团转，我们永远也搞不清它的模样。维系于古已有之的道，以驾御现实的具体存在。能懂得返本复初，是维系于道的基本点。
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