'Somdatta, who is never seen eating during the day time, is continuously gaining weight. Therefore, she must be eating during the night time.' According to classical Indian philosophy, which means of knowledge is used in the above statement?

The reasoning uses postulation (arthapatti), where an unexplained fact is made intelligible by assuming something else.

The observed fact is that Somdatta gains weight though she is never seen eating by day.

This fact cannot stand without a hidden cause, since weight gain needs eating.

To remove the apparent conflict, night-time eating is postulated as the only explanation.

Such reasoning that supplies a necessary presupposition to resolve an inconsistency is arthapatti.

It differs from inference because it assumes rather than derives through pervasion.