 The Sarvāstivāda-Vaibhāṣika distinction between a dharma’s activity and capability implies that each dharma or consciousness moment effects the next moment within its series, but it can also act as a contributory condition towards producing a different sort of effect. Activity engenders the next moment within a dharma’s series, while capability generates a different effect and explains the causal efficacy of past dharmas. Williams (1981, 246–247) helpfully notes that we may render this “horizontal” and “vertical” causality, within a consciousness series and transcending it respectively. For example, an instant of visual awareness horizontally produces the next moment of visual awareness and may or may not, depending on other factors such as light and so on, vertically produce vision of the object. “It follows that to be present is to have horizontal causality, which may or may not include vertical causality—a fact which serves to remind us that we are dealing here with primary existents which are frequently positioned within the system in terms of what they do” (ibid). Thus activity or horizontal causality—a dharma’s function of precipitating the next moment of its own consciousness series—individuates that dharma as a particular event of its kind. A dharma’s capability or vertical causality, by which it facilitates the occurrence of other dharmas outside its consciousness series, locates it within the web of interrelations that connects it with the incessant rise and fall of other dharmas, and hence further individuates it as that very particular dharma by manifesting its unique quality and intensity of operation.