Are the Five Consciousnesses Discerning in Dreams?

The states experienced in dreams are all Image-Only Objects; they are all mental sense-objects, lacking the relatively more real five sense-objects of actual characteristics. Because the five sense-objects are absent, the Image-Only Objects are incomplete and deficient, and when the solitary mental consciousness alone discerns the mental sense-objects, the discernment is not very clear—it is only approximate and highly illusory and unreal. Therefore, the mind consciousness and the manas cannot discern very clearly, and mistakes are inevitable; sometimes the errors are especially numerous and especially great, often amounting to misattributing one thing to another. In dreams, the manas's discernment takes the leading role, and the manas's wisdom of discernment is not strong with unfamiliar states; it lacks accurate judgment, so what it discerns is murky and unclear.

If there were five sense-objects in the dream, the five sense consciousnesses would participate in the discernment, and then there would be no difference from the waking state; there would be no dream state and no sleep at all.