老子「知」的哲學歷程，是「突破」的理性展現，他採取的路徑與孔子迥然不同。孔子由具體的禮樂制度，凝鍊成「仁」的價值；老子以「真知──自知──知人」銷損的方式，拈出「道」的純粹。老子透過「知」了解有欲、無欲的世界，其「知」橫跨「超現實界」與「經驗界」。老子的「真知」，突破人們篤信的神造之說，以「知古始」引領人們真知「道」為萬物之宗。「自知」大多涉及「道用」，討論不爭、謙退、貴虛、守靜的人生議題，其昀高境界是「知不知」。「知人」探討「道術」，統治者應透過「智」認識天下，無為而治，謹守不逞強、戒矜、戒伐的原則。真知──自知──知人，從超現實界的知，銷損至偏重經驗世界的知，老子將哲學的玄妙與現實世界，勾連得十分順美。

The philosophy history of "know" of Lao-Tzu is the rational show of "breakthrough". The way he had taken is totally different from the Confucius’s. Confucius condensed the value of "benevolence" from a specific ritual system. Lao-Tzu brought up the pure "Tao" from "Real know ─ Know yourself ─ Know human". Lao-Tzu understood the desire and desirelessness by means of "know" which spans "surreal world" and "experience world". The "Real know" of Lao-Tzu broke through people’s devout belief in God. In the process of "knowing the origin of the universe", Lao-Tzu led people to realize "Tao" as the fundamental law of all things on earth. "Know yourself" mostly relates to "the use of Tao". It discusses no fighting, modest retreat, peace, keep quiet on the question of life. The highest level is "know what you don’t know". "Know human" explores "Taoism". Rulers should understand the world through the "wisdom", inaction, and keep not show off its power, not to be arrogant and no more war. "Real know ─ Know yourself ─ Know human", from the know of surreal world downgrades to the know of experience world, Lao-Tzu makes a smooth and perfect connection between the mysticism of philosophy and the real world.