"18 aspects of emptiness." as taught in the Maha^prajn~a^pa^ramita^-su^tra （摩诃般若波罗蜜经T 223）. Internal emptiness， external emptiness， internal/external emptiness， empty emptiness， great emptiness， ultimate emptiness， conditioned emptiness， unconditioned emptiness， final emptiness， beginningless emptiness， dispersed emptiness， emptiness of nature， emptiness of self-marks， emptiness of all dharmas， emptiness of non-attainability， emptiness of non-existence， emptiness of existence， emptiness of existence and non-existence.