Only Through the Manas's Deliberation and Investigation Can One Attain Realization

Only when the manas can deliberate (manana) and investigate can one attain enlightenment. And in order for the manas to participate in the investigation of the Dharma's meaning, there must be meditative concentration (samādhi); only then can the Dharma's meaning penetrate deep into the manas. Without meditative concentration, the manas is unable to exert any force. If one forcibly engages in contemplative practice (vipaśyanā-caryā) without meditative concentration, that is called guessing and emotional speculation with intellectual understanding—and everyone already knows what the outcome of that would be. Therefore, the relationship between meditative concentration and enlightenment, and the relationship between the manas and enlightenment, must be thoroughly understood and made clear before one can set about applying effort to investigate Chan.