Material World is Impermanent
It became one of my favourite chapters in The Laṅkāvatāra Sūtra when I read the chapter for the first time a few years ago as Mahāmati asked the Buddha.
“Bhagavan, your teachings about neither arising nor cessation, nirvana, ignorance, impermanence, and delusion, etc. are not unique because non-Buddhists are teaching the same. Bhagavan also uses the same worldly terms to describe the Truth,” Mahāmati asked (Not a literal translation, but to give the gist of the question)
The Buddha replied, “No, my teachings are not the same as that of the non-Buddhists. I teach neither arising nor ceasing that is not established on the dualistic indications of perceived and perceiving.”
《楞伽阿跋多羅寶經》卷4〈一切佛語心品〉：「佛告大慧：『我說一切法不生不滅，有無品不現。』」(CBETA, T16, no. 670, p. 506, a21-22)
Any individual understands that material world is impermanent. It is also the basic practice for Hinayana practitioners to observe the five aggregates to eliminate their self-attachments. So when the non-Buddhists heard that the Buddha taught about impermanence of the material world or nirvana, they interpreted those terms with their best comprehension – literally. Initially based all phenomena on worldly theories and logic, the practitioners could observe that worldly matters are indeed of dependent arising; actually, they are correct – for mundane issues.
When people state that all dharmas are impermanent, the theories are based on worldly matters to start with – all dharmas which manifest within the three realms; if a foundation is mundanely built, its original existence of entity cannot be everlasting.
But the Buddha taught the root cause of all the mundane existence; in other words, the origin of matters that brings forth dependent arising to the three realms, which does not belong to the three realms. The Buddha taught the perpetual non-discerning Buddha nature.
It (the Buddha nature) is without any form or appearance, if the Buddha did not use language to describe Its unique characteristics to the disciples, who could understand any thing about It? While the Buddha explained with terms and languages, listeners would interpret the teachings with their own understandings. It is because we are limited within the scope of our conceptual mind.
That is why to get “awakened” is so important in Buddhist cultivation, through personally realizing and verifying the Buddhist teachings, the practitioners’ eyes can penetrate the sutras (figuratively speaking) and catch the gist and will be able to study further.
That is also the drastic distinction between the Mahayana practitioners and the Hinayana practitioners. The former personally witness the state of nirvana during life time, while the latter cultivate their fourth fruits of arhatship based on eliminating their eighteen sense-realms, after passing away, arhats just vanish from the three realms (liberated from cyclic births and deaths). Arhats have never personally witnessed their Buddha nature, because all their practices are limited and based on the worldly eighteen sense-realms. (A very concise summary only, detailed descriptions are available upon request)