The Logic of Ish

For centuries, human beings have returned to a single, inexhaustible question: What is the ultimate ground of reality? Across civilizations, the answers have taken the form of myth, revelation, and inherited faith. Yet in ancient India, a distinctive intellectual movement arose that sought to approach the divine not through scriptural authority, but through reasoned inquiry. The Logic of Ish explores this remarkable tradition. It traces the arc of Nyāya philosophy—from Ācārya Gautama and Ācārya Vātsyāyana to the profound synthesis of Udayanācārya—examining how these thinkers developed one of the world’s most rigorous systems of logic and applied it to questions of causation, agency, moral order, consciousness, and the conditions of knowledge itself. Their undertaking was neither mystical speculation nor doctrinal dogmatism, but a disciplined attempt to determine whether the concept of Īśvara can be established through rational means. Anchored in Udayanācārya’s Nyāyakusumāñjali, this book brings the classical arguments into conversation with contemporary philosophical and scientific contexts. The term Ish – a reference to Īśvara, also stands for Intelligent System Heuristics, a framework for understanding order and structure within complex systems. In this confluence of scripture and algorithm, the search for a divine ground becomes a lens for deciphering the logic of the cosmos itself. Moving between historical debates and present-day questions, the work revisits problems that remain fundamental: What constitutes valid evidence? Can inference reveal what lies beyond direct perception? How should divergent worldviews engage one another? And where do the limits of rationality itself begin? Clear in exposition and rigorous in analysis, The Logic of Ish reintroduces a major philosophical tradition to the global discourse. It invites readers—scholars, skeptics, and seekers alike—to consider how humanity, across time and cultures, has used the tools of logic to contemplate its place in an intricate and enigmatic cosmos.