大般涅槃經義記 6.16

6.16

The above seven approaches are the emptiness of lack of nature. As for 'non-existence', seeing that the marks of causes and conditions are also non-existent is called 'emptiness of non-existence'; this is markless emptiness. Hence it is said below: 'Just as a person without a son is called empty, not that emptiness of lack of nature is clarified in terms of a son; and also just as a poor person without possessions is called empty, not that emptiness of lack of nature is clarified in terms of possessions.'