起信論疏筆削記 20.24

20.24

然上所說，依經明其三觀行相，似成別異。若在行人，即須三智一心中得，不縱橫並別，方是圓修也。天台空觀即此止門，假觀即觀門，中觀即俱運也，大約如此。

However, what was explained above clarified the mental marks of the three contemplations according to the sūtras, which seem to constitute distinct differences. In the practitioner, however, the three knowledges must be attained within the One Mind—neither longitudinal nor transverse, neither combined nor separate—before it is complete cultivation. Tiantai's contemplation of emptiness is this gate of calming (śamatha); the provisional contemplation is the gate of contemplation (vipaśyanā); and the contemplation of the Middle Way is their concurrent operation. This is roughly how it is.