  The first clause is to prevent self-causation. The import of the second condition is that entities similar to c must always exist with entities similar to e. There must be an invariable or constant conjunction between c-type entities and e-type entities. This rules out objects which just happen to be there, such as, to give the Naiyāyikas’ example, a donkey happening to wander past the pottery just as the potter goes to work. This feature of the account, the insistence that a causal relation instantiates a regularity, resembles a Humean account of causation. The Naiyāyika, however, recognised the possibility of ‘accidental’, non-causal regularities, such as day always preceding night, or (the example given by The Manual of Reason), the colour of the thread always preceding the cloth. Although the occurrence of a cloth is invariably preceded, not just by threads, but by the presence of thread-colour as well, we would not want to say that thread-colour is a cause of cloth.  The third clause is their attempt to eliminate such accidental regularities. The same clause is supposed to stop the cause of a cause (e.g. the potter’s parents) from being a cause. Its meaning, however, is not quite clear. Literally, it states that a cause must be ‘not established otherwise’. Kalidas Bhattacharya says that “an invariable antecedent is irrelevant if knowledge of it is not required for any anticipative knowledge of the origination of the effect” (see Potter 1977: 67). Matilal says that an antecedent is irrelevant if “it is possible to find a reasonable explanation of its appearance” (1985: 290). The Manual of Reason states that an antecedent is irrelevant if its antecedence is only established along with some other entity. We know that thread-colour precedes cloth only because we know that it occurs with the thread (which we know to precede cloth); hence the thread-colour is irrelevant in this sense.  This highlights an asymmetry between the two regularities, the threadcolour-cloth regularity and the thread-cloth regularity. For while we can establish the latter directly by observing correlations between thread and cloth, we establish the former by observing the correlation between threadcolour and thread. Thus the former supposedly depends on the latter but not vice versa. It is not clear, however, that the dependence does not run the other way too. In any case, in using this criterion to block transitivity, the Naiyāyikas seem to seeking a definition not of causality per se (which most regard as a transitive relation), but rather an epistemic notion of ‘causal explanation’ or ‘causal salience’.