 Seeing classical Indian logic as part of epistemology, as explaining how we know facts through the mediation of our knowledge of other facts, makes it easy to understand why both the Buddhist and Vedic schools count a valid but unsound argument as fallacious: knowledge is not generated. Classical Indian philosophers are not focused on logic per se, but rather on a psychological process whereby we come to know things indirectly, by way of a sign, hetu or liṅga, an indication of something currently beyond the range of the senses, whether at a distance spatially or temporally or of a sort (such as atoms or God or the Buddha mind) that by nature cannot be directly perceived.