Why are postulation (arthāpatti) and inference not the same thing?

Arthāpatti ‘postulation’ is the instrument of knowledge through which we know that Devadatta is out given that he is alive and not home. In Classical India, just like among contemporary scholars, several thinkers (especially of the Nyāya school) have tried to show that it is only a subset of inference.

Within the weekly reading group facilitated by Malcolm Keating, we are reading the section on arthāpatti of the Mānameyodaya by the Bhāṭṭa Mīmāṃsaka Nārāyaṇa Bhaṭṭa. This week, we read the part on the difference between inference and postulation according to the Prābhākaras.

It is often the case that neighbours hate each other, and Nārāyaṇa does in fact attack the members of the rival school of Prābhākara Mīmāṃsā much more violently than the Naiyāyikas. The Prābhākaras agree with the Bhāṭṭas against the Naiyāyikas that the arthāpatti is distinguished from inference, but they disagree as for why this is the case.
Nārāyaṇa uses various arguments, the last of which is that the invariable concomitance between what one knew before and what one discovers during that cognitive process is already available only in the case of inference. In other words:

  1. inference: one knows already that smoke is invariably concomitant with fire
  2. postulation: one knows only at the end of the process from “Devadatta is alive and not home” to “Devadatta is out” that “being alive while not being home” is invariably conomitant with “being out”

By contrast, the Prābhākaras use a different argument to distinguish the two, namely that the hetu ‘logical reason’ in the case of inference is firmly established, whereas it is doubted in the case of postulation. In other words:

  1. inference: one infers that there is fire on the mountain because of smoke (firmly established)
  2. postulation: one ascertains that Devadatta is out because he is possibly alive (doubted reason)

This being said, please enjoy the depiction of these positions and most of all the witty refutation of the Prābhākara one by Nārāyaṇa:

Before having ascertained that [Devadatta] is outside [his] home, the conjunction of being alive and not being home could not be known. […]

This has been said in [Kumārila’s] Bṛhaṭṭīkā*:

Therefore, the absence from home which is understood in regard to one who is present (i.e., alive) |

this [would be] the probans (if the postulation were a case of inference), but this is not seized before seizing that [the alive person] is out of his home || 143 ||

(tasmād yo vidyamānasya gṛhābhāvo ‘vagamyate | sa hetuḥ sa bahirbhāvaṃ nāgṛhītvā ca gṛhyate)

Therefore the postulation is indeed distinguished [from the inference].

By contrast the Guru (Prabhākara), who does not known this (mentioned above) tool to destroy the Naiyāyikas, has prattled on the doubt about the being alive in this case [as the trigger of postulation]: || 144 ||

“The being alive indeed has been known before as being home |

Thereafter, there must be doubt about his being alive due to the fact that one has not seen [Devadatta] in his home || 145 ||

But the doubted fact of being alive can convey the fact that he (Devadatta) is out of his home |

This is the advantage [over inference] of the postulation, that although it is doubted it conveys [something] || 146 ||

In this way, if there is a doubt regarding the fact of being alive the probans would have a doubted qualification. In this way the refutation of the status of inference is very easy for us! || 147 ||”

[Bhāṭṭa:] That is ridiculous! To elaborate:

If the fact of being alive were doubted because one has noticed that one is not home |

then the ascertainment of that (being alive) would be done, on the basis of assertions of reliable speakers and so on || 148 ||

or by means of considering signs such as the auspicious necklace (worn by married women who are not widows, so that its presence on the neck of Devadatta’s wife would be a clear sign of his being alive) of his beloved one |

But this is not desired at all [by the Prābhākara] (who in fact does not undertake any of these things). Therefore [in reality] there is no doubt at all [even in the Prābhākara’s mind] || 149 ||

Moreover, one does not seize that [Devadatta] is out on the basis of a doubtful idea that he might be alive |

for, if one doubts that he might also be dead, how could the idea that he is out [originate]? || 150 ||

“Since he is alive or not, he is out” |

who else apart from the Guru (Prabhākara) would be able to postulate that? || 151 ||”

*By the way, do you happen to know this verse from some other source? (Or do we have to imagine that Nārāyaṇa Bhaṭṭa still had access to the then lost Bṛhaṭṭīkā?)

For more on postulation, on Nārāyaṇa’s Mānameyodaya and on our reading sessions, please see this post.

Comments and discussions are welcome. Be sure you are making a point and contributing to the discussion.

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11 thoughts on “Why are postulation (arthāpatti) and inference not the same thing?

    • Thank you, Bama, you are becoming my favourite reader:-)
      As for the correct translation of arthāpatti, there are different hypotheses, ranging from postulation, to inference to the best explanation, abduction and presumption. I often use “cogent evidence”.
      My reason for avoiding inference to the best explanation, abduction and presumption is that these terms evoke a precise epistemological position (as in Peirce), one which might be misleading, since it is not identical with arthāpatti. But this has to do with the more general problem of translations, for which one might want to read also the comments to this post: http://indianphilosophyblog.org/2015/02/23/tricky-words-prap/

  1. We know how arthapatti works. It’s a bit like a switch where there is disjunction between the two values, on/off, true/false, yes/no. Plump Devadatta does not eat during the daylight hours therefore he must be eating at night. If one state is known i.e. alive and not at home then the other state is immediately know i.e. outside the home somewhere. Postulation does not apply. Postulation may be shown to be correct or it may be impossible to show whether or not it is. Think of Hig’s Boson and Kant’s Transcendental Postulate. We are attempting to reach towards a picture of how things must fundamentally be for things to appear as they do. Arthapatti is not tentative in any sense.

    I can see where ‘assumption’ or ‘presumption’ may not be a perfect fit for what arthapatti does. There is no ‘before’ for arthapatti, there is no ‘after’ for arthapatti. Implication doesn’t fit. Knowing that plump Devadatta is fasting during the day is knowing that he eats at night. Implications have to be worked out so this is not one. Arthapatti has a bi-polar nature. It is basic and irreducible.

    • interesting points, Michael, you convinced me as for “postulation”. What about “cogent evidence” or similar paraphrases?

      • I wrote the following paragraph before I read your response. There is a general difficulty in the explanation of basic
        powers. Ostensive definition has the problem of knowing what it is you are pointing at. (I admit to being an unreconstricted Wittgensteinian)

        If I might add. Even if the Sanskrit has the sense of apatti – artha then it too is explaining the simple in terms of the more complex and that cannot be a good explanation. Here as Wittgenstein wrote – ‘my spade turns’. If the complex has the simple embedded in it then circularity ensues. Simply by having a human mind you get ‘switches’ in the ‘kit’.

        • Thank you. I agree to the opinion that arthāpatti may not be presumption, but since doubted reason is involved – the postulation may depend on the chances of truth, in mathematical term – probability. And that’s the reason I was thinking that arthāpatti is closely related to presumption rather than postulation.

          The switch example is good and illustrates a binary relation. And, it goes well with Devadutta’s example. But, is arthāpatti also binary in general?

          • Bama:
            The presumption or assumption or cogent reasons come in I think as that background knowledge or context or common sense that humans lay down in the course of their experience. Our responses then are acquired automatisms particularly in the case of stop/go situations. This common sense is what robots lack. A robot if given the task to remove a bomb from a room (Daniel Dennett’s example) will find the bomb but because the bomb is chained to a trolley will attempt to remove the chain in order to remove the bomb.