A Monk asked Zhaozhou, "Does a dog have a Buddha-nature or not?" Zhaozhou said, "Yes."
The monk said, "Since it has, why is it then in this skin bag?"
Zhaozhou said, "Because he knows yet deliberately transgresses."
Another monk asked Zhaozhou, "Does a dog have a Buddha-nature or not?"
Zhaozhou said, "No."
The monk said, "All sentient beings have Buddha-nature—why does a dog have none, then?"
Zhaozhou said, "Because he still has impulsive consciousness."

Commentary: If you say a dog's Buddha-nature surely exists, afterwards he said 'no'—if it surely does not exist, still previously he said 'yes.' And if you say that to say 'yes' or 'no' is just a temporary response spoken according to the situation, in each there is some reason. That is why it is said that someone with clear eyes has no nest.

The point of this monk's question was to broaden his perspective and learning; he didn't base it on his own fundamental endowment. Zhaozhou said 'yes', using poison to get rid of poison, using sickness to cure sickness.

This monk also said, "Since it has, why is it then in this skin bag?" He didn't realize he himself had been born in the belly of a dog. Zhaozhou strikes twice; a fleeting opportunity is hard to catch.

This monk might have thought that he was judging the result on the basis of the cause, but if you understand in this way, you cannot even be the slave of a professor.

Later a monk asked this again, whereat Zhaozhou said 'no'. He was one who had attained—whether he said 'yes' or 'no' he had a way out. This monk judged the fundamental way on the basis of words: "All beings have Buddha-nature; why doesn't a dog have it?" Thus challenged, I dare say that even the hand that can move the North Star has no way to turn around, but Zhaozhou answered sincerely with this: "Because he still has impulsive consciousness." Now you tell me—did this monk have blood under his skin after all? Tiantong cannot avoid putting more moxa to burn on the scar on the red flesh:

Verse: A dog's Buddha-nature exists, a dog's Buddha-nature does not exist;
A straight hook basically seeks fish who turn away from life.
Chasing the air, pursuing fragrance, cloud and water travelers—
In noisy confusion they make excuses and explanations.
Making an even presentation, he throws the shop wide open;
Don't blame him for not being careful in the beginning—
Pointing out the flaw, he takes away the jewel;
The king of Chin didn't know Lian Xiangru.

Commentary: "A dog's Buddha-nature exists, a dog's Buddha-nature does not exist"—the two parts are not the same; he brings them out together, just like Xuedou's "One has many kinds, two have no duality." Tiantong wants to meet with Zhaozhou, that's why he versifies in this way. Yingtian Zhen said, "A straight harpoon catches ferocious dragons, a curved hook catches clams."

Afterwards, "chasing the air, pursuing fragrance," like hunting dogs they make excuses and explanations in noisy confusion. What juice is there in a dry bone?

Дело скорее в том, что если природа будды есть у вас, то она будет и в чём угодно.

Склоняюсь к тому, что для живых существ природа будды присутствует в любом куске материи лишь потому, что мир "кусков материи" - это мир, что существует только в уме у живых существ (поэтому этот мир "одушевлён", т.е. принимается за реальность).
Реально, мир материи - это нечто однородное (смотрим метафизику с её теориями), где формы являются лишь информацией, не более... Мир форм - это только лишь некая "умышленная прослойка" в бесконечном однородном пространстве пракрити.

В школе нас учили, что способность (по)знания универсальна, так как природа (по)знания - отражение. А отражение можно найти и в самом грубом куске материи. Примерно так рассуждает и Санкхя-Йога. Саттва, что собственная природа просветленности, находится везде, правда, в разных пропорциях.

Природа будды отражается в зеркале поросячего ума и в результате получается природа свинства.