俱舍論記 17.9

17.9

「為此依此至異此不然」者，答中有三：一為此根本彼加行方轉故、依此根本彼後起方轉故，故加、行後起非是根本。二又前說此根本業道攝麁品故，加行、後起非麁品故，非業道攝。三又若由此惡業道有減，令內外惡物有減；由惡業道有增，令內外惡物有增。若由此善業道有減，令內外好物有減；由善業道有增，令內外好物有增。有斯用者，立為業道。異此根本，前、後不然，故非業道。又解：若由此惡業道有減，令內外好物有增；由惡業道有增，令內外好物有減。若由此善業道有減，令內外惡物有增；由善業道有增，令內外惡物有減，立業道名。異此不然。又解：若由此惡業道有減，令內外惡物減、好物增；由惡業道有增，令內外惡物增、好物減。若由此善業道有減，令內外好物減、惡物增。由善業道有增，令內外好物增、惡物減，立業道名。異此不然。言內外物者，《婆沙》一百一十三云「所居名外，壽等名內。」

Regarding the passage "For this, relying on this ... otherwise it is not so": Within the answer there are three points: First, because the preparatory stage [of an action] proceeds only for the sake of this fundamental [course of action], and its subsequent stage proceeds only relying upon this fundamental [course of action], therefore the preparatory and subsequent stages are not the fundamental. Second, also, it was previously said that these fundamental courses of action subsume the coarse grades; because preparatory and subsequent stages are not coarse grades, they are not subsumed under courses of action. Third, also, if by the decrease of this unwholesome course of action, internal and external bad things are made to decrease, and by the increase of the unwholesome course of action, internal and external bad things are made to increase; and if by the decrease of this wholesome course of action, internal and external good things are made to decrease, and by the increase of the wholesome course of action, internal and external good things are made to increase—those which have this function are established as courses of action. Different from this fundamental, the preceding and subsequent stages are not so; hence they are not courses of action. Another explanation: If by the decrease of this unwholesome course of action, internal and external good things are made to increase, and by the increase of the unwholesome course of action, internal and external good things are made to decrease; and if by the decrease of this wholesome course of action, internal and external bad things are made to increase, and by the increase of the wholesome course of action, internal and external bad things are made to decrease—[then] they are designated courses of action. Otherwise it is not so. Another explanation: If by the decrease of this unwholesome course of action, internal and external bad things decrease and good things increase; and by the increase of the unwholesome course of action, internal and external bad things increase and good things decrease; and if by the decrease of this wholesome course of action, internal and external good things decrease and bad things increase; and by the increase of the wholesome course of action, internal and external good things increase and bad things decrease—[then] they are designated courses of action. Otherwise it is not so. As for the words "internal and external things," the Mahāvibhāṣā, fascicle 113, states: "Dwelling places are called external; life-span and the like are called internal."