 Udayana (Nyāya, eleventh century) appears to inherit a sixfold division of tarka according to the nature of the error in an opponent’s position, and expressly lists five types (a sixth, “contradiction” or “opposition,” either being assumed as the most common variety, or subsumed under Udayana’s fifth type, “unwanted consequence”). Philosophers from other schools present distinct but overlapping lists. The Nyāya textbook-writer, Viśvanātha, of the early seventeenth century, mentions ten, Udayana’s five plus five more, many of which are used by the Advaitin Śrīharṣa (probably Udayana’s younger contemporary) among other reasoners. They are: (1) self-dependence (begging the question), (2) mutual dependence (mutual presupposition), (3) circularity (reasoning in a circle), (4) infinite regress, and (5) unwanted consequence (including contradiction presumably)—Udayana’s five—plus (6) being presupposed by the other, the first established (a form of “favorable” suppositional reasoning), (7) (hasty) generalization, (8) differentiation failure, (9) theoretic lightness, and (10) theoretic heaviness.