成唯識論演祕 3.161

3.161

所緣幻化，有為不實，故譬毛輪。有云：說境微細，或境多故，故類毛輪勘。

The cognitive object is illusory, conditioned and unreal, hence it is compared to a hair-net. Some say: it means the object is subtle, or because the objects are multiple, hence it is compared to a hair-net; this should be examined.