A cause is outlined as an unconditional and invariable antecedent of an effect and an effect as an unconditional and invariable consequent of a cause. The same cause produces the same effect; and the same effect is produced by the same cause. The cause is not present in any hidden form whatsoever in its effect.

The conditions mentioned below should be met:

The cause must be antencedent (Purvavrtti)

Invariability (Niyatapurvavrtti)

Unconditionality (Ananyathasiddha)

Nyaya recognises five kinds of accidental antecedents (Anyathasiddha):

Just an accidental antecedent. E.g., The colour of the potter's cloth.

Remote cause is not a cause because it is not unconditional. E.g., The father of the potter.

The co-effects of a cause are not causally related.

Eternal substances, or eternal conditions are not unconditional antecedents. e.g. space.

Unnecessary things, e.g. the donkey of the potter.

Nyaya recognises three kinds of cause:

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.