楞伽阿跋多羅寶經註解 1.231

1.231

此釋大慧所問有為生法、無為不生法，涅槃、虛空、剎那流轉等法，皆妄想所現，初無自性。

This explains Mahāmati's questions regarding conditioned arising dharmas, unconditioned non-arising dharmas, nirvāṇa, empty space, momentary flux, and other dharmas: they are all manifestations of vikalpa, and from the beginning lack svabhāva.