Zen Master Jōshū once asked his teacher, Nansen, “What is the Way?” Nansen answered, “Ordinary mind is the Way.”
This may be true, but as Dogen explains it, to learn the Way as ordinary mind is extremely rare. To learn the Way as ordinary mind is to realize that both the body and the mind are always completely ordinary, and that there is never the slightest taint nor any trace of design.
Dogen wrote two separate essays titled Butsu-Kojo-No-Ji (The Matter of the Ascendant State of Buddha). One is included as Chapter 28 of the Shobogenzo anthology, but the other appears only in a shorter, "Secret Shobogenzo" collection. To paraphrase Dogen from his second essay as it appears in the "Secret Shobogenzo," in our everyday state of mind, we do not describe yesterday as today, nor describe today as tomorrow. We think of mind and body as separate. The is the ordinary state of mind, but people are prone to misunderstand the ordinary state of mind and dismiss it as if it were just so many hundreds of weeds. However, we can intuitively understand that those hundreds of weeds are themselves ordinary. It is because the ordinary state of mind is the Way that the hundreds of weeds do not wither or rot. If the Buddhist patriarchs were not ordinary, they could never have gotten free from the world, forgotten themselves, and practiced the Way, for practice of the Way is naturally ordinary.
However, Dogen warns us, if we think that because ordinary mind is the Way we need not practice, we misunderstand ordinariness. Practice and experience are themselves completely ordinary. There being none that is not ordinary, there can be none that is tainted. "It is not that practice and experience is nonexistent," Nansen later taught, "but it cannot be tainted."