道之體與道之德是同一個道。道之體是道之德賴以產生的實體，道之德是道之體的功能、作用。這種體用關係，表明二者密切聯繫，內在一致。同時，二者作為道的兩個層面，又各有特徵。老子從道的體與德之區別著眼，提出了有與無、有名與無名、道與一、動與靜、妙與徼等對偶範嚼，以及有生於無、道生一等觀點。

　　　　　Tao's substance and its virtue is one and the same thing. The former depending on the latter engenders reality, and the latter is the function of the former. The relation of substance and virtue indicates that they are closely interwoven with each other, and have inner coherence. Meanwhile, they are two aspects of Tao, and have respective characteristics. Lao Tze starting from the distinction of substance and virtue of Tao proposes the principle of opposites: yu and wu, yu-ming and wu-ming, Tao and one, miao and jiau; and the notion of that yu is from wu and that Tao begets one etc.