首楞嚴義疏注經 10.332

10.332

因細得名也。此是諸識之中串習機要，亦名精明湛不搖處，故云湛了，即本識也。有而若無，故云罔象。罔，無也。象，似也。非有形質，故曰虛無。望前行陰最為其細，再三示云微細精也。

Its name is derived from its subtlety. This is the crucial nexus of habitual practice among all consciousnesses, also called the state of essential clarity and tranquil unmovingness; hence it says "tranquil clarity," which is the fundamental consciousness. Being present yet seeming absent, it is called "elusive." Wang means absent; xiang means resemblance. Lacking physical form and substance, it is called "insubstantial." Compared to the preceding aggregate of formations, it is the most subtle; repeatedly it is shown to be "subtle and essential."