 According to this view, the relationship between conventional truth and ultimate truth is analogous to the relationship between the appearance of falling hairs when vision is impaired by cataracts and the absence of such hairs when vision is unimpaired. Although this is a metaphor, it has a direct application to determining the relationship between the two truths. Conventional truth is like seeing falling hairs as a result of cataracts: both conventional truth and such false seeing are illusory, in the ontological sense that there is nothing to which each corresponds, and in the epistemological sense that there is no true knowledge in either case. Ultimate truth is therefore analogous, ontologically and epistemologically, to the true seeing unimpaired by cataracts and free of the appearance of falling hairs. Just as cataracts give rise to illusory appearances, so ignorance, according to Sakya, gives rise to all conventional truths; wisdom, on the other hand, gives rise to ultimate truth. As each is the result of a different state, there is no common link between them in terms of either an ontological identity or an epistemological or conceptual identity.