Anand Vaidya has recently raised a very intriguing discussion on modality in Indian philosophy. His post started with the suggestion that modality is less central in Indian philosophy than it is in Western thought. In the comments, several scholars suggested examples hinting at reflections on modality also in Indian thought but, now that I think again about them, they mostly discussed the modality of possibility in Indian thought. What about necessity?
Mark Siderits, in his Nyāya Realism, Buddhist Critique (in The Empirical and the Transcendental, edited by Bina Gupta), mentions without further elaboration that Nyāya philosophers were “innocent of the notion of necessity” (p. 223). I think he is making or hinting at a valid point, in the sense that realist schools like Nyāya are much less inclined than Buddhist Pramāṇavāda to stress the need of logical necessity. In other words, Buddhist Pramāṇavādins will stress points such as the fact that the coexistence of (seemingly) conflicting characteristics in the same entity is logically impossible and that, consequently, the existence of atoms (which should be basic units but also extended in space) is impossible and that the non-existence of atoms is therefore a logical necessity.
By contrast, realist authors are much more committed to the existence of what sense perception attests to and would thus not subscribe to the idea that the lack of logical consistency can cause one to deny the existence of what we experience in the world. This is even more true in the case of Mīmāṃsā, since Mīmāṃsā authors are programmatically committed to worldly experience (lokavyavahāra). Thus, it is hardly the case that Mīmāṃsā authors will ever speak of logical necessity as contradicting worldly experience. Worldly experience is the primary instrument of knowledge (pramāṇa) and it cannot be contradicted because of purely logical reasons. By contrast, if there seems to be logical reasons contradicting our sense perception, it is our logical reasons which need reconsidering since they have probably led to a fallacy.
Moreover, the principle of self validity (svataḥ prāmāṇya) basically makes data count as if they were necessarily true, unless and until they are contradicted by a later, more precise, cognition.