中國古代思想家在探討自我或人的問題時，通常是通過對「性」此一概念的探討來進行的。先秦兩漢儒者對性的討論十分豐富，而其共通處在於，他們都是在「人之所受以生者」這樣的思考方向下，檢討人之所以稱得上是人、其所稟受的內容究竟為何。但這種思考方向，在佛教進入中國後開始受到批判。梵語使用者是從「體」的角度來思考「性」的問題，事物的實質稱之為體，體的不變異者稱之為性。古漢語所說的性，在佛教思想家看來，是因認知與為作而生，因此只是「有為法」的性。真正的體，必須是無為法、甚至是佛，而由此歸納出的性就是法性與佛性，而對佛性的探究，也成為南北朝至唐代佛教思想的核心。中土在吸納佛教思想的過程中，利用漢語來翻譯由梵語所構造的世界觀與思維方式，由此遂產生了漢梵思維的融合，張載的天地之性、氣質之性二分的說法，正是在此背景下成立。氣質之性言個體所受以生之性，這是古漢語的思維方式，而天地之性則是在講真實不變的性體內容，這是受到梵語思維的影響，張載用「本來性」與「現實性」的架構，來安置此兩種性之間的關係，代表漢、梵思維的融合。此種說法提出後，一方面解決了先秦兩漢儒家有關人性論的爭議（未能對本來性有較深入的探討），一方面又能批判佛教佛性論在實踐上會面臨的困境（無法對個體的現實性賦予太多肯定），因此很快就得到其他理學家與內丹派所接受，成為近世儒、道思想的核心理論。

Ancient Chinese philosophers usually explore humans through the concept of “nature.” The discussions in pre-Qin and Han dynasties Confucianism on human nature are based upon a common thesis: nature is “what human beings receive to live.” This approach is criticized after the introduction of Buddhism to China, as Sanskrit users meditate on human nature from the perspective of invariability. Buddhists think that the ancient Chinese concept of human nature is samskrtadharma (conditioned dharmas) for it is developed from phenomenal recognition, while the true nature should be asamskrta-dharma (unconditioned dharmas) or even Buddha, which can be furthermore comprehended in terms of dharmata (dharmanature) and buddha-dhatu (Buddha-nature). Therefore, the search of buddha-dhatu becomes the core of Buddhism from the Southern and Northern dynasties to the Tang dynasty. During the incorporation of Buddhism into central mainland China, the translation of Sanskrit cosmology and thought into Chinese bring about the fusion of Chinese and Sanskrit thoughts. Amid this context originates Zhang Zai’s theory of heaven-earth nature and psycho-physical nature. The psycho-physical nature means the nature which human beings receive to live, which conforms to ancient Chinese concepts; the heaven-earth nature refers to the true and unchanging nature, which is influenced by Sanskrit thought. Zhang Zai uses the structure of “inherent nature” and “realistic nature” to relate the two concepts of nature. As a synthesis of Sanskrit and Chinese thought, this structure resolves the pre-Qin and Han dynasties debate over human nature and the predicament of buddha-dhatu practice. Hence very soon it is accepted by other Neo-Confucianists and the Daoist school Neidan (internal alchemy) and becomes the core theory of modern Confucianism and Daoism.