What Is the Second Moon?

Original text of the Sūtra of Perfect Enlightenment (Yuanjue Jing):善男子。一切众生。从无始来。种种颠倒。犹如迷人。四方易处。妄认四大。为自身相。六尘缘影。为自心相。譬彼病目。见空中华。及第二月。 

Explanation: The Buddha said: Good men, since beginningless kalpas, all sentient beings have constantly harbored various inverted views and thoughts in their minds, like a person who has lost his way, wandering in all directions, ceaselessly searching for his own belonging. Due to a lack of wisdom, they groundlessly take the material body composed of the four great elements to be their own body, and take the images of the six sense objects conjured up through conditioning to be the appearance of their own minds. They go so far as to be fully convinced and to affirm that the material body of the four great elements is "I," and that the images of the six sense objects are the appearance of their own mind, without the slightest doubt, clinging to them stubbornly unto death; for beginningless kalpas they have been sinking in the river of birth and death, unable to attain liberation and escape. When the inverted minds of sentient beings perceive these illusory marks, it is just like diseased eyes seeing flowers in the sky or a second moon. The second moon seen by diseased eyes in fact does not exist—there is only the first moon, the true moon; likewise, all the dharmas seen by inverted beings are not nonexistent—they are nothing but the true suchness of one's own mind. When will sentient beings be cured of their illness and no longer be inverted, no longer take the false marks as real, and see only the appearance of the true mind?