The fallacy concerning middle term is known as hetvabhasa. If the middle term does not provide sufficient ground to justify the conclusion, then hetvabhasa is committed.
Hetvabhasa thus signifies fallacious reasoning. Five such material fallacies are possible. Those are:
1. Savyabhicara or the irregular middle. When the middle term is not invariably related to the major term, the conclusion is likely to be false.
2. Virudha or the contradictory middle – When the middle term is not related to the major term but to its contradictory, this fallacy arises.
3. Satapratipaksa or the inferentially contradicted middle – when the conclusion can be contradicted by another middle term justifying the opposite of the conclusion, this fallacy arises.
4. Asidha or the unproved middle – This fallacy arises when the middle term has not been proved in the premises such a fallacy takes place.
5. Badhita or the non-inferentially contradicted middle. When the conclusion brought out by the middle term is disproved by some other praman, this fallacy arises.