吉藏繼承興皇法朗以來，所主張的「二諦唯是教門，不關境理」這一觀 點，最終所要彰顯的是什麼？再者吉藏於其諸著書中，為何處處提及「中道是 二諦體」這一概念呢？這是否與《大乘玄論》卷第二所說「中為正宗，二諦為 傍」、「理為正，教則傍」等觀點有著內在的關係？ 又「二諦」與「三諦」之間，祇是「有時攝 ‧ 三諦為二諦」、「有時開 ‧ 〔二 諦〕則有三諦」，或「開理、教為三諦」之「開、合」不同，或者僅是「用 正」、「體正」的差異而已嗎？ 此中，吾人藉由「以楔出楔」的手法，並以吉藏的「四重二諦」內容，作 為探索本文的切入點。附帶一提的是，在討論與釐清的過程中，筆者會「以吉 藏說吉藏」的方式，引證並陳述、證成與釐清二諦、三諦「此一」議題。 當然，有關吉藏的二諦與三諦之開展與內在連結，吾人擬從（1）對「三 諦」之解讀及其立場；（2）從「二諦」或「三諦」的彼此相攝內容；（3） 「二諦」或「三諦」擇一所可能產生的過失；（4）就眾生根性以觀機說法； （5）隨其眾生所患而因病施藥；（6）約說法的重心、特色與隱顯之差別，來 看「二諦體」或「三諦義」均是以「非……非……」之定型句的形式陳述。因 此，筆者以為吉藏所要表達的訊息是「正道未曾有無」而已──「實無二諦，方便說二」、「隨順眾生故說有二諦」、「無有三諦；但隨順眾生說有三 諦」。但因「眾生悟入不同，故適化多種」，「於一義作種種說」，故二諦、 三諦（乃至「涅槃」、「〔正因〕佛性」等義）「皆是轉勢說法，各示一 門」，而「名部雖異，斥病顯道，其義大同」，它衹是「轉側適緣」罷了。

Chi-Tsang inherited Hsing-Huang Fa-Long’s thought and proposed the theory of “two truths as an instruction, not the principle of objective realm.” What kind of picture did it provide on this theory? Why did Chi-Tsang frequently indicate the concept of “middle path as the substance of two truths” in his commentaries? Is there any correlation among this concept and the concepts of “middle path as the primary, two truths as the secondary” and “principle as the mainstream and instruction as the minority” in the preachings of Ta Cheng Hsuan Lun? Whether at all “two truths” and “three truths” proposings are only the comparisons of differences between quotations of “three truths incorporated into two truths” and “two truths elaborating with three truths,” the difference between specific and elaborative interpretation of “principle and instruction concerning three truths” or the difference between “function” and “substance”? This article starts with an investigation on these questions by using the method of “knocking off a wooden nail with a small one” and Chi-Tsang’s “four levels of two truths.” Besides, in the process of discussion and clarification, this author uses “Chi-Tsang’s own words to analyze Chi-Tsang’s concept” and attempts to prove this discussion by taking quotations, descriptions, justifications and clarifications of “two truths” and “three truths.” This author tries to explain the development and the internal link between “two truths” and “three truths” with the following viewpoints: (1) The foundation and explanation of “two truths” and “three truths.” (2) The correlation between “two truths” and “three truths.” (3) The possible drawbacks of choosing either one of them. (4) Dharma preaching according to human nature. (5) Giving medication according to the symptoms of sentient beings. (6) Using the same sentence structure of “non-…non-…,” according to the focus, characteristics and the difference between expressive and implicit of Dharma preaching, to summarize and illustrate the concepts of “two truths” and “three truths”. Therefore, this author assumes that the only information Chi-Tsang delivered is that “there is neither existence nor nonexistence of the noble path”—the existence sayings of “two truths” or “three truths” are introduced only in accord with the needs of sentient beings. However, in order to accommodate the different awakening levels of sentient beings, there are many ways to interpretate the same truth. Therefore, the two truths and the three truths, as well as Nirvana and Buddha nature, are the same access to the noble path. Despite of the fact that the two truths and the three truths are merely two different adaptive means with two different terminologies, they are both able to cure the sentient beings’ illness and to characterize the noble truth.