《莊子．天下》篇，把老子思想學說總結為：「建之以常無有，主之以太一，以濡弱謙下為表，以空虛不毀萬物為實。」其中，前兩句是最能夠貫穿老子的宇宙本源，而用以這一些概念來描繪其宇宙之理論體系的。對此，學者的歧見，言人人殊，紛然相雜，從斷句、注釋到解析都各執一端。不過，若能揭示《老子》首章之旨，則《莊》述意義可豁然貫通。梁啟超開始做出「常無」、「常有」的解釋，大體上與「道」之體用為一體的觀念類似。梁啟超所謂「建之常無、常有之兩元，而實歸宿於一」的解析，以及許抗生所言「『常無有』與『太一』皆指的是老子的『道』」。然則，若「常無有」分讀成詞，恐未免偏離老子的原義，故蔣錫昌說：「若必欲字字而分別之，則將愈別愈晦矣。」可見，《老子》一書闡明「無」、「有」同出於「道」而異名，而其首章乃全書「眾妙之門」。因而其宇宙思想，應該還是繞著「無」、「有」體用的關係，實有必要敘述各項有關「道」之涵義。

　　　　　《Chuang Tzu．Tien-Hsia》(《莊子．天下》) concluded the thinking of Lao Tzu as follows: "It is to be established on eternal existence and nonexistence, headed by extremely unification. Its appearance becomes weak and humble, yet its essence is based on All Creature of empty and undamaged quality. "The first sentence would most likely linked up with the thinking of Lao-Tzu on Universal Origin. However, scholars held various opinions on this. Some of them argued about its punctuation, and some explained from different points of connotations and analysis. If one can delineate the theme in the first chapter of 《Lao Tzu》, he will be able to understand completely the meaning of 《Chuang Tzu》. Mr. Liang Chi-chao (梁啟超) was the first man who asserted the dualism between "eternal existence" and "eternal nonexistence". Mr. Hsu Kang-sheng (許抗生) further explained that "both of 'the eternal existence and nonexistence' as well as 'the extremely unification' are referre9 to the Taoism." On the othe rhand, as Mr. Chiang His-chang (蔣錫昌) pointed out, "It would be too obscure to understand the true meaning of Lao Tzu word for word. "Obviously, Lao-Tzu elaborated 'existence' and 'nonexistence' both from 'Taoism' but in different words. His thinking on the universe should be concentrated on the relationship between 'existence' and 'nonexistence'. Therefore, it would be necessary to discuss the meaning of 'Taoism'.