傳統禪宗的修行重視「以心傳心」，也就是師師傳承的關係。在禪法興盛的時代，禪修者通常能很幸運地在一位乃至數位大禪師座下修行到禪悟的發生。另外，有一些禪修者也能把握正確的禪修方法與觀念，當修行到開悟，再找所謂的過來人來勘驗印證自己的悟境。此外中國禪宗的另外一個重要原則是：「唯論見性，不論禪定解脫。」這都說明禪的修行重視於把握「禪慧」的大原則；相對的，對於禪修過程中的身心反應並沒有那麼重視。十八世紀後半工業革命的發生，人類在科技文明有著空前的進展，理性主義隨之抬頭，人們也要求從事人文精神領域的工作者，用各種科學方式來提出合理說明，包括宗教也不例外。以佛教之禪修而言，近年來國際上對「禪與腦」或「開悟」的研究絡繹不絕，正是代表在這一大環境下所產生的趨勢。我們可以看到歷代禪宗文獻中記載著頗多有關開悟的例子，而其中一個很明顯的身心反應是：禪修者禪悟的當下，會有「通身汗流」現象。若是夏天的禪期，禪修的人要流汗太容易了，但是本文所探討的，並非是因天氣熱而汗流滿身，而是一種禪修者在發生禪悟時所產生的身心反應現象。的確，到目前為止我們尚無法提出反證來說：若禪修者沒有汗流滿身的話，他就一定尚未發生禪悟。但從另外一方面說，我們也可提出另一種可能性：有禪悟而汗流滿身的禪修者，並不一定將此經驗說出來而被記錄於後世的文獻之中。當然，只因禪修而發生了汗流滿身現象這一點而言，是不能夠拿來做為禪悟時「心印心」的勘驗標準，因為在禪宗紀錄中，並沒有看到用「滿身大汗」來驗證禪修者是否達到禪悟境界。然而，禪宗的典籍或當代資料中的確留下非常多如此事例的記載—包括聖嚴法師的禪修經驗在內，這值得將來進一步從跨領域研究中來探索它的奧祕，比如禪修與神經心理學或心理生理學等領域。此外，聖嚴法師從小就親歷無數天災人禍之痛，而激發一究生死迷惑之問題。雖然無人指導他去參一個公案或話頭，卻也憑一己之善根，自然地將許多內心的疑問匯歸到同一個中心問題上去—生命的疑情。這突破了傳統參話頭的型式，讓他更深刻地掌握到從「疑」到「悟」—從「修」到「證」的內涵與意義，此後數十年中，於東方與西方開展出更靈活的各式禪的教學方法。法師在見到靈源老和尚的前一年（1957）之中，他寫了許多佛教文章；文思暢通無礙，並都能匯歸到自己的中心思想上，這讓很多人以為他是開悟了。又在一九五八年春天，也就是在見到靈源老和尚的前三個月之中，都保持在疑（疑情、疑團）的狀態，這明顯地是從「思」到「修」的歷程。聖嚴法師與太虛大師可說有相似的修證歷程。我們看到太虛大師在十九歲時，閱讀《般若經》而發生第一次禪悟體驗後，也有「伸紙飛筆，隨意抒發」的狀況；其後在二十八歲時的第二次禪觀中就開悟了。可見兩位大師的禪悟中也都有明顯的思、修、證之歷程。中國禪宗雖開展出不同於印度佛教的修行方法，但有聞、思、修、證的共通歷程上，仍然與印度佛教是一致的。

The practice and cultivation of the Traditional Chan (Zen) School emphasizes “Mind-to-Mind Transmission” in which the teaching is passed from a Chan master to their disciples and heirs as an unbroken lineage of teacher and disciple relationship. In the golden age of Chan , practitioners can easily find a Chan master, or even many, to learn and practice Chan to achieve enlightenment. For those without a master, if they can seize and follow through the correct concepts and methods of Chan practice and finally awaken to the truth, they can also find a teacher—one called “the experienced”—to examine and corroborate if they are truly enlightened. In addition, the other important principle of Chinese Chan School is to “pursue seeing the nature, not meditative liberation.” This illustrates that Chan practice focuses much more on seizing the grand principle of the realization of wisdom, than on the reaction to one’s body and mentality during the practice. The Industrial Revolution, which started from the later part of the 18th century, produced the greatest advances in technology and engineering for the modern civilization. Rationalism arose consequentially, asserting that in the field of humanistic studies, including religion, the truth should be explained and determined by scientific methods and factual analysis. In Zen Buddhist practice nowadays, the popularity of the study of topics such as “Zen and the Brain” and “Enlightenment” among international scholars and researchers growing trend attempting to view and explore Zen meditation and its effects on the human body in a scientific way. In the historical literature of the Chinese Chan School, many episodes and cases have been documented regarding the phenomenon of Chan Enlightenment. A conspicuous occurrence noted in this literature is “sweating all over”. Obviously what is being referred to here is the physical and psychological reaction the practitioners experienced while becoming enlightened, not the sweating due to the heat of the weather, which can easily happen during retreat in the summer. So far, we don’t have any counterevidence to show that if a practitioner does not “sweat all over,” he is surely not yet enlightened. On the other hand, we can also assume that not all the practitioners who had the experience of “sweating all over” during enlightenment did indeed mention this to others and/or have it documented, in order to become part of the historical record. However, the traditional Chan School uses “mind-sealing-themind”, an intuitive method independent of the spoken or written word, to evaluate and corroborate whether the practitioner is already enlightened. The single physical phenomenon of “sweating all over” during enlightenment can hardly be a criterion for this corroboration. Furthermore, there is no record in the Chan School literature indicating that such a criterion was ever used. But the author shows many exemplary cases documented in the Chan School scriptures and literatures, as well as the case of the Chan meditation experience of Master Sheng Yen himself. It is worthy to explore the mystery with further studies from an interdisciplinary approach, such research based on Chan meditation and Neurophysiology or psychobiology. In addition, from childhood, Master witnessed numerous natural and man-made disasters which inspired him to explore the predicament of life and death. Although there was no one to guide him to practice Koan or Huatou, due to his own good merits, innumerable inner doubts naturally converged to his inner issue—a doubt sensation of life. He broke through the traditional practice formula of Huatou, and could more profoundly grasp the connotation and meaning of Zen Meditation—from “doubt” to “Enlightenment.” This influenced him to employ more flexible kinds of Zen teaching methods in the East and West for decades. In 1957, which is the year prior to his meeting with Master Ling Yuan, Master Sheng Yen wrote many Buddhist articles. His thoughts on Buddhism flowed very smoothly, and could converge to his inner Buddhist ideology, which made many people think he was enlightened. By the spring of 1958, when he met with Master Ling Yuan, Master Sheng Yen’s doubt sensation (or doubt mass) had already lasted for three months. From “thinking” to “practicing,” this clearly a common course for practicing Zen Buddhism. It could be said that Master Sheng Yen and Master Tai Xu shared a kind of similar practice and enlightenment course. When Master Tai Xu, at the age of 19, reading Prajñāpāramitā-sūtra, he experienced a Samādhi experience and then could “write down extreme quickly, feel free to express his Buddhist thought.” In the second Samādhi meditation, at the age of 28, he went into a profound enlightenment. Obviously, there are the same practice processes for the two Masters: from “thinking” to “practicing” and from “practicing” to “enlightenment.” Even Chinese Buddhism carried out such a kind of Zen meditation practice different from the Buddhism of India, but each Buddhism keep the common course containing four processes: “hearing, thinking, practicing and enlightenment.”