The present collection of articles in this special issue of Journal of Indian Philosophy is a result of a thematic session on “Logic in the Religions of South Asia”, a separate section of the 2nd World Congress on Logic and Religion (held at the University of Warsaw, Poland, June 18–22 June, 2017), which gathered about 180 philosophers, mathematicians, Orientalists, specialists in religious studies and theologians eager to analyse different aspects of the relations between logic and religion. Broadly, the topics addressed both in the thematic session and in other sessions of the Congress covered such questions as the impact of religious beliefs on logical structures, the problem of the rationalisation of religious beliefs, the nature of proof and justification in religious legal traditions, the relation between logic illogicality in religion, the application of non-classical logics to the questions of religion, the role of logic at the service of apologetics, models of argumentation in religious discourse, etc.

A number of these questions are addressed in the papers that have ensue from the South Asian session, while some additional contributions of those who could not participate in person provide certain new dimensions, to jointly result in this collection.

The first paper is Johannes Bronkhorst’s “Logic and language in Indian religions”, which sets out in very general terms how views of language, arising from religious practice, shaped religious and philosophical thought in classical India as regards the relation between language and reality. Bronkhorst identifies two important presuppositions underlying Brāhmaṇical philosophical reflection. The first is the view that each word denotes something real. The second, which Bronkhorst calls the correspondence principle, is that each true sentence denotes a situation constituted by the denotations of the words in it. These presuppositions, which have their origins in the recitation of mantras by Brahmins in Vedic ritual, contrast with the central presupposition of early Buddhist thinkers regarding language. As a result of their focus on the mind and experience, Buddhist thinkers viewed reality as comprising fleeting atomic experiences, called dharmas, and nothing else. A consequence they drew from this view is that common sense objects, which are the denotations of words, are illusory and hence do not exist.

Considering the way philosophical thought in classical India was shaped by presuppositions about language and in light of the sophistication of its grammatical tradition, one might wonder if thinkers in classical India had entertained the possibility of there being truths arising from the nature of language itself, and which could therefore be known a priori. The question of whether or not something corresponding to a priori knowledge is to be found in the Indian philosophical tradition is taken up by John Taber in his paper, “Some Remarks on the Apparent Absence of a priori Reasoning in Indian Philosophy”. Taber concludes that indeed Indian thinkers did not identify any truths as necessary truths nor any statements as statements known a priori. Rather, it seems, all knowledge is grounded either in observation or in revelation. To show this, Taber examines doctrines and arguments in Indian philosophy where one should expect a reference to a priori reasoning, and where one does find such a reasoning in Western philosophical thought, for example, in arguments for the existence of God.

Arguments for the existence of God do occur in classical Indian philosophy. A particularly important work devoted exclusively to proving God’s existence is An offering of the flowers of logic (Nyāya-kusumâñjali), a treatise in the Nyāya tradition dating from the beginning of the 11th century by Udayana. It has been widely accepted that this important theistic work was composed in a mix of verse (kārikā) and prose. This contention, however, is contested by Ferenc Ruzsa in his article “Structure and authorship of the Kusumâñjali”. In this study, Ruzsa analyses its structure, distinguishing between what appears to be an earlier text, consisting of sixty-five ślokas (Nkś) together with its extensive commentary (Nkp), mainly in prose, and what appears to be a text later added. The evidence for his comes from certain points of disagreement between these two hypothetical layers. As the author makes clear, confirmation of his hypothesis would require the examination of additional material, including unpublished commentaries on the Nyāya-kusumâñjali.

Three hundred years later, in the same tradition as that of Udayana, Gaṅgeśa (c. 1325), whose magnum opus, the Tattva-cintā-maṇi, re-energized the Nyāya tradition, made a critical assessment of arguments for God’s existence. Stephen Phillips, in his article “The Logics of Counterinference and the ‘Additional Condition’ (upādhi) in Gaṅgeśa’s Defense of the Nyāya Theistic Inference from Effects”, examines the treatment of one widely discussed argument for God’s existence. The argument, relying on the premiss that every effect has a cause, concludes that the universe has a cause and that its cause is God. In particular, Phillips examines the context and structure of this argument. A part of his examination includes consideration of Buddhist criticisms of this argument. These Buddhists observe that one can very well accept the conclusion that the universe has a cause without accepting that the cause is a conscious agent. The analysis of the argument leads Phillips to conclude that, as against a general view of Gaṅgeśa as a staunch theist, he was in fact less committed to theism than it has so far been presumed, and one of his main goals of the extensive excursus on God’s existence is to reflect on and to illustrate philosophical reasoning per se in its proper form. One might be even tempted to say that the question of the existence of God becomes subordinate to the paradigm of argument proper, and the existence God is at the service of logic.

This line of Nyāya theological thought, as discussed in this collection of articles, extends up to the nineteenth century. A modern representative of the Navya-Nyāya school Maheśa Chandra (1836–1906) offers a highly interesting development of this tradition of logic, and proposes a theory of interrogatives expressing doubts and of declaratives expressing certitudes that can both be regarded as the verbal expression of cognitions, as interpreted by Eberhard Guhe in his article “Maheśa Chandra’s Exposition of the Navya-Nyāya Concept of “Cognition” (jñāna) from the Perspective of Inquisitive Logic”. This theory is subsequently applied to an highly sophisticated analysis and refutation of the so-called “dubious associate condition” (saṃdigdhôpādhi), already discussed by Phillips in connection with Gaṅgeśa, that could be used by opponents to undercut certain Nyāya arguments for the existence of God.

In most of the articles collected in this issue of Journal of Indian Philosophy, the authors discuss theistic religious-philosophical traditions of South Asia, only with occasional references to non-theistic and non-Brāhmaṇic schools, primarily Buddhist, and therefore God often stands in the focus. An important exception, which provides a broader perspective on the relation between logic and religious thought, is Marie-Hélène Gorisse’s analysis of the juncture of logic and religion in Jainism, which she presents in her article “Evaluating the reliability of an authoritative discourse in a Jain epistemological eulogy of the 6th c.”. The case she examines is that of Samantabhadra, a prominent sixth-century Jaina philosopher, who undertakes to formulate logical arguments to prove the omniscience of the Jain teachers. Instead of following a standard method, already used by Dharmakīrti, of demonstrating that one’s scriptures are authoritative due to their coherence and to being uncontradicted by perception, inference or other criteria of cognitive reliability (pramāṇa), Samantabhadra chooses to follow a peculiarly Jaina approach. According to the Jains, ordinary assertions are only “contextually valid”.Therefore they are not universally valid, hence are fallible. Samantabhadra resorts to Jaina epistemological theory of non-one-sidedness in order to establish the authority of the Jinas, as discussed by Gorisse. It remains to be seen whether thinkers who do not acknowledge the validity of Jaina non-one-sidedness theory of “contextually valid” assertions, which stands at the bottom of Samantabhadra’s argument, would accept his proof as convincing and valid.