How did Chinese – and hence Japanese – Buddhism get to the universality of Buddha Nature?
How did that broadening happen, so that people were eventually able to say, around the 8th century, that all beings have Buddha Nature?
Later, Dogen creatively reinterpreted that formulation as all beings are Buddha Nature. Everything is Buddha Nature. Not just certain sentient beings, sometime in the limitless future, but everything, now: trees, clouds, sky, everything.
Arguably, the belief is there from the beginning, but in a slightly obscured form.
The three trends which constitute Chinese Buddhism are Madhyamaka, Nagarjuna’s approach—the whole emptiness perspective; Yogacara—mind only; and Tathāgatagarbha—the idea that within each of us is this essence of Buddhahood.
These are all Indian perspectives that come to China, the first two as specific schools. None of them thrived long term in their original form. Chinese Buddhism incorporated them into the specifically Chinese schools of Tiantai and Hua-yen in the 6th and 7th centuries, which in turn birthed the Zen school of meditation and the Pure Land school of devotionalism and other power. (That’s why Zen is often mistakenly seen as standing apart; you have to go through several layers to understand it, and it’s easier to talk superficial ahistorical nonsense)
In these three Indian perspectives we can see, in unstated form, this universality of Buddha Nature.
In Madhyamaka the overriding idea is that everything is empty, nothing has an independent, subsisting self, everything arises and ceases depending on causes and conditions. Although ‘emptiness’ was expressed as something disruptive and new, one can see how that perspective is identical with the original Buddhist perspective as taught in the 12-fold chain and so on. Why?
Because who is a Buddha if not someone who not just sees dependent origination, but lives it, and all that that implies?
The idea of the universality of Buddha Nature is also there in the three natures of the Yogacara school. The first nature is the imaginary nature. All the qualities that we impose on everything that we see— the smoothness of the cup, the softness of the air, all of that constructed world is the imaginary.
When a person is able to see the dependent arising of everything, that is the second nature—the dependent nature. When that person – paradigmatically in meditation: the ‘yoga’ in Yogacara means meditation – is able to experience in their being this interdependent arising, not as something external, not as something thought, but something involving all of them, all of their experience, there’s a potential pivot to the third nature.
And that third nature is Suchness, which arguably, although it’s not stated in this way, is congruent with and supportive of the gradual shift towards the universality of Buddha Nature, although ironically the School fell out of favour in China because of Xuanzang’s denial of this.
Alongside all this, there’s a change in what’s meant by Buddha Nature. Originally Buddha Nature, Buddhahood was something to be achieved in the future, after a great deal of effort and practice. We can see that, on the surface anyway, in the text of The Lotus Sutra, where predictions were made of people being buddhas in future lifetimes.
But saying that everything has Buddha Nature or that Buddha Nature is everything changes it fundamentally.
Rather than thinking of Buddha Nature or Buddhahood as being, as it were, a picture of the biggest wave in the ocean, each living wave, now, is the full manifestation of the ocean.