The Buddha himself once said that there were quite a few inconsistencies in his teachings in order to suit the taste of different audience, but the one that would never change is the teaching on emptiness.  For example, from the point of view of relative truth, impermanence and suffering being the nature of all phenomena are deemed absolute truth, but not from the point of view of the ultimate truth. In the Three Dharma Seals, only no-self is deemed the absolute truth.

- Quote from The Right View, "Buddhism—the Definition"