維摩經略疏 3.81

3.81

問：沫等與炎等何別？答：沫等有此色質，但是虛假，分折易空。以人不知色身空故，用此為譬。炎等似有，實無體質，以此無質譬於麁細有質之色，知諸法皆空。

Question: What is the difference between foam and so forth, and mirage and so forth? Answer: Foam and the like have this physical form, but it is merely provisional and false, easily analyzed into emptiness. Because people do not know that the physical body is empty, these are used as similes. A mirage and the like seem to exist, but actually lack physical substance; using this lack of substance to serve as a simile for gross and subtle physical forms with substance, one knows that all dharmas are empty.