大般涅槃經集解 68.64

68.64

案僧亮曰：實處無故則不遍，應是無常。二處無者，實處無空、空處無實也。

Sengliang comments: Because it does not exist in solid places, it is not pervasive and should be impermanent. 'Nonexistent in two places' means that there is no space in solid places, and no solid in empty places.