Sutra 2.2.20

20. There not being (a cause), there results contradiction of the admitted principle; otherwise simultaneousness.

If it be said that the effect may originate even when a cause does not exist, then—as we have pointed out before—anything might originate anywhere and at any time. And not only would the origination of the effect thus remain unexplained, but an admitted principle would also be contradicted. For you hold the principle that there are four causes bringing about the origination of a cognition, viz. the adhipati-cause, the sahakāri-cause, the ālambhana-cause, and the samanantara-cause. The term adhipati denotes the sense-organs.—And if, in order to avoid opposition to an acknowledged principle, it be assumed that the origination of a further momentary jar takes place at the time when the previous momentary jar still exists, then it would follow that the two momentary jars, the causal one and the effected one, would be perceived together; but as a matter of fact they are not so perceived. And, further, the doctrine of general momentariness would thus be given up. And should it be said that(this is not so, but that) momentariness remains, it would follow that the connexion of the sense-organ with the object and the cognition are simultaneous.