Lama Michel Rinpoche explains (in English with a French translation) the four fundamental pillars or ‘seals’ that characterize Buddhist thought. If all these four seals are found in a path or a philosophy, it can be considered the path of the Buddha.
The Four Seals are:
All composed phenomena are impermanent
All impure phenomena are of the nature of suffering
All phenomena are empty and lack intrinsic existence
Beyond suffering there is peace
The Four Seals of Buddhism, Lama Michel Rinpoche – May 2013, Geneva
