The following conditions should be met:
 The cause must be antencedent [Purvavrtti]
 Invariability [Niyatapurvavrtti]
 Unconditionality [Ananyathasidha]
Nyaya recognizes 5 kinds of accidental antecedents [Anyathasiddha]
[a] Mere accidental antecedent. E.g., The colour of the potter's cloth.
[b] Remote cause is not a cause because it is not unconditional. E.g., The father of the potter.
[c] The co-effects of a cause are not causally related.
[d] Eternal substances, or eternal conditions are not unconditional antecedents. e.g. space.
[e] Unnecessary things, e.g. the ass of the potter.
Nyaya recognizes 3 kinds of causes:
 Samavayi- material cause. E.g. Thread of a cloth.
 Asamavayi- Colour of the thread which gives the colour of the cloth.
 Nimitta- Efficient cause, e.g. the weaver of the cloth.