The First Moon, the Second Moon, and the Shadow Moon

Original text of the Śūraṅgama Sūtra, Volume Two: 佛告阿难。且汝见我。见精明元。此见虽非。妙精明心。如第二月。非是月影。 

Explanation: The Buddha told Ānanda: The seeing essence with which you can see me is the origin that can discern material form. Although this seeing essence is not the wondrous, pure, luminous fundamental mind—the tathāgatagarbha—it is like the second moon, not a reflection of the moon. 

The "second moon" and the "seeing essence as the luminous origin" that the Buddha speaks of here refer to the seeing nature of the tathāgatagarbha, but not the most subtle seeing essence and luminous mind; that is to say, the seeing nature of the seeing essence and luminous origin is the subtle seeing nature of the tathāgatagarbha. The "reflection" refers to the images perceived by the seven consciousnesses, composed of earth, water, fire, wind, and space. 

This involves the relationship among the first moon, the second moon, and the moon's reflection. The first moon refers to the actual moon hanging high in the sky as seen by the eye consciousness. The second moon is an identical, simulated false moon produced by pressing the corner of one's eye with a finger—a virtual image formed by the eye consciousness due to misaligned focus, also called a double image. Therefore, as long as the first moon is real, one cannot say the second moon is false. The shape, color, and every state of the second moon are exactly the same as the first moon; by seeing what the second moon is like, one knows what the first moon is like.

For example, suppose I have a file on my computer and send it to you over the network. The file on my computer is the source file, similar to the first moon; the file you receive is a copy, similar to the second moon, exactly identical to my source file. You cannot say that the file you received is the source file on my computer, nor can you say that the file you received is not the same file as the source file, a fake file. Another example: you take a notice and photocopy it on a copying machine. The black characters on white paper that come out are exactly the same as the original document. You cannot say the photocopy is different from the original document, nor can you say the photocopy is the original document; but when you see the photocopy, you know what the original document is. Such is the relationship between the first moon and the second moon.

What, then, is the moon's reflection? The moon's reflection is the shadow cast by the moon in the sky into a river. It is similar to the first moon yet also different: in both shape and color it differs from the first moon, and it also differs from the second moon. If the river water flows with shimmering ripples, the reflected moon will become distorted, and its difference from the first and second moons becomes even greater; therefore it is more illusory than the second moon. The reflected moon does not emit light and cannot illuminate; it can only be admired and has no practical value.

The tathāgatagarbha is the first moon; the seven consciousnesses are the second moon; the moon's reflection is the dharma manifested through the combined transformation of the three transforming consciousnesses. What is meant by "combined transformation" is that the tathāgatagarbha directly gives birth to dharmas by means of seeds; the seventh consciousness directly influences and facilitates the tathāgatagarbha's production of dharmas; the six consciousnesses influence the choices and intentions of the seventh consciousness; and the seven consciousnesses together discern and manifest the dharmas in the mind—thus dharmas appear. The moon's reflection is the dharma manifested in the minds of the seven consciousnesses; it is extremely illusory, without substantial function or value, like the water and fire in a mirror, which can neither quench thirst nor burn. Yet sentient beings do not know this, and the seven consciousnesses do not know it; they continually grasp at the moon's reflection, scooping at the bright moon in the sea, and in the end it is all in vain.