《老子》中有三個最重要的概念：道、無、有。要言之，道是真理，無與有表示道這真理的形上性格。但無一概念的內容非常豐富，經筆者細心研究，發現無一概念起碼有六面意思。一、指本體的道。道是客觀的實體，是實際存在的，且是天地萬物成立和滋長的超越依據。無亦是這個意思。二、是本體的道的描述語。無表示道以沖虛為體，由此可產生無窮妙用，包括創生萬物在內。 三、表示道的虛無為用。虛無狀態之能有用，由於 " 反 "的義理。四、表示工夫修行。要撤除一切的障礙，化解人生的挫折。五、表示處事方法或態度。這便是無為和無不為。無為是不妄為，不刻意做些干擾人的本性的事。能如此，則一切都能辦得妥當，這便是無不為。六、指主觀的實踐境界。即在主觀的心上實現客觀的道而成的一種沖虛的精神境界。 貫串無的這六面意義的，是虛無的狀態。這是客觀的道的性格，也是主觀的心境。老子是《老子》或《道德經》一書的作者。他的哲學有三個最重要的概念，這便是道、無、有。如下文所表述那樣，道是老子心目中的真理，無與有是道這真理的形而上性格，老子又視道為無，而無與有又有相對相關的密切關係。故無似乎介於道與有之間，是老子哲學的一個關鍵概念。了解了無，老子哲學的整個輪廓與根本精神，便能把握得到。 故本文即以“老子哲學的無的概念之探究”為題，闡述與探討老子的哲學。 很多研究老子哲學的學者，都不會忽視他的無的概念。他們通常認為這無的意義有兩個層次：其一是指作為客觀實體的道，另一則是一般的意思，指不存在，是有無的無。（1）這樣理解自然是對的，不過，筆者認為並不足夠，不夠全面，也不夠具體。筆者以為，老子的無有以下多面的意思：它指本體的道，是本體的道的代語：它也指道的虛無為用，也涵有工夫修行及處事方法或態度的意思：另外，它也指一種主觀的實踐境界。這樣理解，自然包含上面的兩個層次的意思。（2）以下我們即就無的這些方面的意思來進行探討。在探討中，我們會廣泛地參考現代學者研究老子哲學的成果，並把重要的說法也推介出來。

　　　　　There are three important concepts in Lao-tzu's philosophy, namely, Tao, Nothing and Being. Tao is the Truth, whereas Nothing and Being represent the metaphysical nature of this Truth. The content of the concept of Nothing is, indeed very abundant. It consists of at least six meanings. 1. It denotes the metaphysical Tao which does exist, serving as the transcendental ground of all entities. 2. It describes the essence of Tao as voidness. Numerous wondrous functions originate from this voidness, including giving birth to all entities. 3. It denotes the various functions based on Tao's voidness. That voidness can induce functions is due to its implication of "return". 4. It involves the implication of cultivation which is achieved in the eradication of all kinds of hindrance and the dissolution of all difficulties. 5. It denotes the methods or attitudes of dealing with daily matters, namely wu-wei and wu pu-wei. Wu-wei means one does not initiate unnecessary actions that will hamper human nature. If one can do so, there is nothing that cannot be done well. This is Wu pu-wei. 6. It denotes a subjective state achieved through practice. That is, one realizes the objective Tao in one's mind, attaining a spiritual state of emptiness. This empty state is Nothing. These six meanings are not separated from each other. They are corelated through the implication of voidness, which denotes, objectively, the nature of Tao, and subjectively, a state of the mind.