Which one of the following fallacious hetu (middle term) is not uniformly concomitant with the major term?

In Indian logic, a fallacy is technically called hetvabhasa, a word that means hetu or reason that appears as a valid reason but is not. Since the fallacies of inference are due to such fallacious reasons, the Naiyayikas consider these only as ones that may infect the constituent propositions of the syllogism.

According to Naiyayikas, there are five kinds of fallacies.

Savyabhicara (the irregular middle):

• The Savyabhicara hetu or the irregular middle lead to no one single conclusion, but to different opposite conclusions.
• This fallacy occurs when the middle term violates the general rule of inference, that it must be universally related to the major term or that the major term must be present in all cases in which the middle is present.
• The Savyabhicara middle, however, is not uniformly concomitant with the major term. It is related to both the existence and non-existence of the major term and therefore is also called an inconstant concomitant of the major term.
• In the example,
  • ​All bipeds are rational; Swan is bipeds;
  • Therefore Swans are rational.
• Here, the conclusion of this inference is false, since the middle term ‘biped’ is not uniformly related to the major term ‘rational’.
• It is related to both rational and non-rational creatures. Such a middle term is called Savyabhicara or the irregular middle.

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Viruddha (the contradictory middle): It is the one that disproves the very proposition which it is meant to prove.

Satpratipaksa (the inferentially contradicted middle): This fallacy arises when the middle term of inference is validly contradicted by some other middle term which proves the non-existence of the major term of the first inference.

Asiddha (the unproved middle):

• It is one that is not yet proved but requires to be proved.
• This fallacy occurs when the middle term is wrongly assumed in any of the premises and so cannot be taken to prove the truth of the conclusion.

Badhita (the non- inferentially contradicted middle): It is the ostensible middle term of inference, the non-existence of whose major is ascertained through some other source of knowledge.

Hence, it is clear that the Savyabhicara middle is not uniformly concomitant with the major term.