Shin fukatoku

Shin fukatoku (Japanese: 心不可得), also known in English translation as The Mind Cannot Be Grasped, is a book of the Shōbōgenzō by the 13th century Sōtō Zen monk Eihei Dōgen.

It was also included as the third book of the 28 fascicle "Eiheiji manuscript" Shōbōgenzō, and a variant of it was fourth in that version as well.

Gudō Nishijima, a modern Zen priest, contrasts the subject of this book with the line of René Descartes "I think, therefore I am", which suggests the intellect can grasp the mind.

Nishijima states that Buddhism is instead only a "philosophy of the here and now" and that Dōgen is telling us the opposite of Descartes: the mind fundamentally lacks substance, cannot exist independently of the outside world, and therefore cannot be grasped.

In order to illustrate this point, Dōgen examines a kōan story about Deshan Xuanjian, a Buddhist scholar of the Diamond Sutra, who attempts to purchase rice cakes from an old woman to "refresh his mind".