" We cannot conceive of the birth of anything.There is only continuation. Please look back even further and you will see that you not only exist in your father and mother, but you also exist in your grandparents and your greatgrandparents. As I look more deeply, I can see that in a former life I was a cloud. This is not poetry; it is science. Why do I say that in a former life I was a cloud? Because I am still a cloud. Without the cloud, I cannot be here. I am the cloud, the river, and the air at this very moment, so I know that in the past I have been a cloud, a river, and the air. And I was a rock. I was the minerals in the water. This is not a question of belief in reincarnation. This is the history of life on Earth. We have been gas, sunshine, water, fungi, and plants. We have been single-celled beings. The Buddha said that in one of his former lives, he was a tree. He was a fish, he was a deer. These are not superstitious things. Every one of us has been a cloud, a deer, a bird, a fish, and we continue to be these things, not just in former lives. "

― Thich Nhat Hanh , The Heart of Understanding: Commentaries on the Prajnaparamita Heart Sutra