The positive in human life often brings out its negative opposite. Laozi recognized the relative nature of choices as to what values to accept. When such a choice is made, it will also give rise to its opposite. Therefore one must closely examine values, language, matters and things.
人間的正面常會逼出自己的反面，老子看到價值認取有相對性，當一個價值被怎麼認取，會形成倒反的價值觀，因此必須對價值觀、語言、存在事物作徹查。