帛書本《老子》第四十章首句「上士聞道，堇能行之」中「堇」字的訓釋目前存在兩種截然相反的觀點：一方認為當讀作「僅」，義為少；另一方認為當讀作「勤」，義為多。從話語語言學的角度看，此句與緊接其後的兩句「中士聞道……」、「下士聞道……」構成遞降關係。從哲學義理的角度看，本體論或宇宙生成論意義上的《老子》之「道」既等於「無」也等於「有」，「玄之又玄」。這兩個角度的分析均說明《老子》之「道」具有深奧難懂、難以把握或難以踐行的特徵。本文認為，將「堇」理解為「少」的觀點彰顯了《老子》之「道」的這一特徵，因而合理正確，而將「堇」理解為「多」的觀點完全否定了這一特徵，不合本章主旨或語義中心，不能成立。

There are two opposite views of the meaning of the character “jin 堇” in the first sentence of chapter 40 of the silk manuscript of the Laozi, “When the best student hears about the Tao, (1)it is barely within his power to practise it / (or2)he practises it frequently”. The former interpretation reads jin as “jin 僅 (barely)”, while the latter reads jin as “qin 勤 (frequently)”. First, from the perspective of text linguistics, the sentence in question forms a semantically descending hierarchy with two subsequent sentences: “When the average student hears about the Tao…,” “When the worst student hears about the Tao…” Second, as far as philosophy is concerned, the Tao in the Laozi equals both “Non-being” and “Being” in its ontological and cosmogonical senses; it is “mystery upon mystery”. Both analyses show that the Tao in the Laozi is characterized by being abstruse and hard to practise. This paper argues that understanding jin as “barely” manifests these characteristics of the Tao in the Laozi and therefore makes sense and is correct, whereas understanding jin as “frequently” does not agree with these characteristics nor with the main idea of chapter 40 and is untenable.