Podcast Summary:

New Books Network — Interview with Rishi Rajpopat
Episode: "Panini's Perfect Rule: A Modern Solution to an Ancient Problem in Sanskrit Grammar" (Harvard UP, 2025)
Date: January 29, 2026
Host: Dr. Raj Balkaran
Guest: Dr. Rishi Rajpopat, Research Assistant Professor, University of Macau

Overview

In this engaging episode, Dr. Raj Balkaran interviews Dr. Rishi Rajpopat about his new book, Panini's Perfect Rule: A Modern Solution to an Ancient Problem in Sanskrit Grammar. The discussion centers on Panini's Ashtadhyayi, the 4,000-rule ancient Sanskrit grammar, the perceived and actual perfection of its system, and Rajpopat’s groundbreaking reinterpretation of a long-contested meta-rule (1.4.2: vipratiṣedhe paraṁ kāryam). The conversation also explores the tradition of Sanskrit commentary, challenges of intellectual innovation in established traditions, and implications for computational linguistics.

Key Discussion Points and Insights

1. Who Was Panini? And Why the Ashtadhyayi? (02:14–05:23)

• Dating and Significance: Panini lived circa 500–350 BCE in today’s Pakistan, North-West South Asia. He authored the Ashtadhyayi, an astonishing system of some 4,000 concise rules governing Sanskrit (02:14).
• Purpose of the Grammar: Designed less to describe or prescribe usage and more to engineer a rule-based, nearly mechanical system that could, in theory, generate all valid Sanskrit words and forms (02:41).
• "He brings the magic alive to… Sanskrit grammar. He brings it to life…"
  — Dr. Rajpopat, (07:06)

2. Descriptive vs. Prescriptive - Sanskrit’s Structure and Uniqueness (05:23–10:24)

• Is Sanskrit's structure inherently special? Dr. Rajpopat asserts that no single language is inherently more structured:

  "I personally don't think that any one language has… a sophisticated structure more than any other… I personally give credit to Panini…" (05:37–07:32).

• The system’s success is due more to Panini’s genius than any extraordinary property of Sanskrit itself.

3. The "Perfect Rule" and the Ancient Problem (10:24–14:22)

• Rule 1.4.2: "vipratiṣedhe paraṁ kāryam" — A meta-rule instructing how to resolve conflict when two rules could apply at once.

• Historically treated as “imperfect,” the rule, and Panini’s system, were encapsulated in layers of commentary introducing additional meta-rules (often needlessly, says Rajpopat).

• On historical complaints:

  “Right from the first scholar to comment on Panini's grammar onwards… everyone treated 1.4.2 as a big burden.”
  (10:39)

4. Tradition of Commentary and the ‘Problem’ of Rule Conflict (14:22–19:34)

• The ancient and medieval grammarians — Katyayana & Patanjali chiefly — misunderstood 1.4.2, adding numerous meta-rules to patch over perceived problems.

• Rajpopat’s view: The problem isn’t with Panini’s rules themselves, but with later interpretations and modifications:

  "The problem is not with Panini's grammar at all. The problem is with how it came to be received and framed." (17:19)

• Types of Rules: Operational, definition, meta-rules (paribhāṣā-s), and the damage caused by misunderstanding meta-rules is much greater than with surface-level operational rules.

5. How the Problem Arose: Katyayana, Patanjali, and Accreted Complexity (19:34–28:25)

• Rajpopat outlines the development of commentaries:

  • Panini → Katyayana (short comments called vārttikas) → Patanjali (the Mahabhashya, a commentary on both).

  • Katyayana faced the issue of rule conflict; his solution was to restrict the scope of Panini’s meta-rule, introducing whole new categories and subsequent “patches,” further complicating the system:

    "By introducing... new categories... you are messing with, at least in my opinion, or tampering with... the ontology of the Paninian system." (28:25)

• Tradition is resistant to admit misunderstanding, often due to cultural dynamics of reverence and intellectual lineage.

6. Rajpopat’s Solution: Reinterpreting Rule 1.4.2 (37:26–44:01)

• Conventional reading: "The later rule (in the linear order of the Ashtadhyayi) wins."

• Rajpopat’s reinterpretation: "Later" (param) means rightmost within the word being derived, i.e., the rule that applies to the rightmost element in the word wins.

  "Every time Panini uses the word param, he uses it to mean right hand side. How ironic that in the one place that the correct interpretation... matters the most, Katyayana and everyone else misinterpreted that term." (41:39)

• This reading aligns with Panini’s usage elsewhere and, when applied, neatly resolves centuries of rule-conflict headaches.

7. Does it Really Work? Pushback and Exceptions (44:09–49:05)

• Critics (mainly traditionalists) challenged this, citing alleged exceptions. Rajpopat analyzed each, noting most stemmed from textual tampering or involved post-Vedic forms not intended by Panini.

• On exceptions:

  “…very, very few cases which were actual exceptions. Some of it was trickery, some of it was just poor doing Panini badly. But there were some exceptions, and I have discussed all of them in the book…” (44:31–45:10)

• On the rare, legitimate case, it often related to an interpolated rule or later recensions.

8. Writing and Utterance: Is the Rule About Text or Speech? (49:05–54:59)

• Is "rightmost" a written or spoken concept?
  • The reinterpretation depends on order of utterance, not script direction: “It is just param, and that means later...what is produced later in the sequence of syllables that one produces.” (51:05)
  • The system’s genius functions irrespective of writing—the rule resolves to the latest (rightmost/last) applicable element in the morphophonological stream.

9. Why the Tradition Couldn't Adapt; Interpolation, Respect, and Power (54:59–59:40)

• Commentators avoided explicit disagreement with predecessors, leading to ever-growing complexity masked as loyalty.
• On tradition's reluctance:

  "They say they all agree with each other... The idea of disagreement is viewed with great suspicion. And especially when an outsider like myself...points out that there are disagreements, that is taken to be a hostile attack…” (58:31)

10. Modern Implications: Computational Linguistics and Teaching Panini to Computers (61:47–73:52)

• Rajpopat argues that his interpretation finally provides a clear algorithm for the whole of Panini’s grammar, paving the way for comprehensive computational implementation.
• Earlier, only subsets could be coded due to ambiguity about conflict resolution; now, the entire system’s rules are machine-teachable.
• On utility and ethics:

  “I really hope that my identity or where I wrote this or which language I wrote it in does not influence what happens next. I really hope that we can teach this rule-based system to the computer.” (65:57)

• Tradition relied on a battery of additional, often arcane, meta-rules and exceptions—a computer cannot mimic this “trickery.”
• Host Raj notes, “It’s only a matter of time until someone does [a computer implementation], and I think you’ll probably be receiving some correspondences from such people.” (73:36)
  Rajpopat warmly invites such engagement.

11. On Writing the Book for Specialists and Non-Specialists (73:52–78:00)

• The book is written to be accessible:
  • Chapter 1: Friendly introduction for linguists and laypeople.
  • Later chapters: Technical deep dives, intellectual history, philosophy of linguistics, computational and theoretical implications.
• Rajpopat encourages readers to approach his work with curiosity—not to accept or reject but to think, and perhaps spark new interest in Sanskrit linguistics.

Notable Quotes and Memorable Moments

• "He brings the magic alive to… Sanskrit grammar." — Rajpopat (07:06)
• "The problem is not with Panini's grammar at all. The problem is with how it came to be received and framed." (17:19)
• “Either you call it perfect and don’t tamper with it, or you admit that it is imperfect, which is fine with me, and then you can tamper with it. But you can’t both call it perfect and tamper with it. It makes no sense at all.” (70:32)
• "In the one place that the correct interpretation of param as right hand side matter the most, Katyayana and everyone else misinterpreted that term." (41:39)
• “The answer can be simple and the answer can help you apply the meta rule universally, as we are now able to do. And for that I'm a fan of Panini's.” (42:50)
• "For the first time, we actually have what can be called an algorithm that can be used to teach Panini's grammar to the computer." (61:47)
• “I do not expect readers to go away thinking I'm right and the tradition is wrong. But what I really hope is that they will go away thinking I want to think more about this…” (78:40)

Timestamps of Key Segments

• Panini's Place in Linguistics: 02:14–05:23
• What Makes Sanskrit Special?: 05:23–10:24
• Introducing "The Perfect Rule": 10:24–14:22
• Tradition’s Handling of Rule Conflict: 14:22–19:34
• Commentaries and Tradition: 19:34–28:25
• Meta-Rule 1.4.2—Old vs. New Reading: 37:26–44:01
• Addressing Criticisms and Exceptions: 44:09–49:05
• Utterance vs. Writing: 49:05–54:59
• Tradition, Orthodoxy, Innovation: 54:59–59:40
• Computational Linguistics Implications: 61:47–73:52
• How the Book is Structured and Meant to Be Read: 73:52–79:59
• Final Reflections: 79:59–80:27

Conclusion

Dr. Rishi Rajpopat’s reinterpretation of Panini’s meta-rule 1.4.2 proposes that the “later” (param) means “rightmost” within a derived word (the latest uttered phonological position), not later in rule serial order. This insight, rooted in philological and linguistic diligence, potentially unlocks the full “algorithmic” perfection of Panini’s grammar, resolves centuries-old debates, and has significant implications for linguistics and computational applications. The conversation animates both the thrill and the challenges of breaking new ground within ancient intellectual traditions.

Rajpopat’s Call: His book aims to spark curiosity, re-examination, and interdisciplinary dialogue, inviting Sanskritists, linguists, historians, and computational theorists alike to engage deeply with both the ancient and the modern.