 A proposal of this kind was possibly first defended by Śaśadhara (fl. 1125 CE), and became popular amongst later Nyāya-Vaiśeṣika  philosophers.[21] Non-superfluity (ananyathāsiddhi) is defined as the property of not being established otherwise, i.e., independently of the effect (kāryād anyaprakāreṇa na siddhiḥ). causation=invariable conjunction ii* is supposed to take care of the problem of irrelevance. The general thought is that factors that are intuitively causally irrelevant to an effect are established not on the basis of the effect, but on the basis of something else. For example, the color of the threads is established on the basis of the threads themselves, and therefore established independently of the effect.