 There is, fortunately, a much better argument for intrinsic momentariness than the problematic vināśitvānumāna. This argument is known as “the inference [of things’ momentariness] from the [mere] fact of [them] existing” (sattvānumāna), and seems to be largely Dharmakīrti’s own invention, first developed in the second chapter of his Pramāṇaviniścaya. If anything exists and is a specific thing rather than another, it is because of its causal efficacy (arthakriyā), or powers to produce such and such effects. Thus, the sattvānumāna reasoning, concisely formulated, is that things are impermanent, i.e., are new things moment after moment, because they are always causally efficient in some way. (Although not stated, it seems to be presupposed that real things are every moment causing some or another different effect. The differences between effects would be subtle ones that often escape our perception.) The key step in the argument is that nothing causes new effects while itself remaining the same. Dharmakīrti, in the opening passages of the Vādanyāya, argues that if something were permanent (nitya), it would be causally inert as it would neither produce its effects all at once (yaugapadyena) nor serially (kramena). Of course, it is the second hypothesis that is the most attractive possibility for an espouser of permanently enduring things: he would hold that a permanent unchanging cause would produce a series of different effects, not because the cause changes in any way, but simply because of the presence of new and different surrounding circumstances.