Nyayasutra: A Manual for Debates

Given the increasingly polarizing times that we live in, far too often have I seen debates that seem to lead nowhere. Words continue to be exchanged but ideas are lost in translation. The instinctual response is to assume that the opponent is either stupid, pushing an agenda or arguing in bad faith. While this may be true in some cases, if both parties are united in their search for truth, well-intentioned arguments can be resolved by a healthy dose of meta-awareness about the protocols of debate.

Rather than consult a modern-day rationality guru (who probably just wants to sell me his latest book) on the topic of structured debate, I decided to look a little further back in the past for inspiration. This brought me an ancient Sanskrit text called the nyāyasūtra. I was glad to see that it wasn’t still covered by copyright and available online for free, thanks to some kind stranger on the internet.

Like a lot of texts from this period, it was probably composed in many layers by multiple authors. According to early estimates, it was initially composed around the 6th century BC by an Aksapada Gautama — not to be confused with the more famous Gautama. This was an exciting time in the Indian subcontinent, there was a flourishing of independent philosophical movements that challenged the traditional Vedic orthodoxy. This is also reflected by several verses (2.1.58–2.1.69) that deal with the inconsistencies and reliability of the knowledge in the Vedas. Vedic, Ajivika, Charvaka, Buddhist and Jain philosophers debated each other on a variety of topics ranging from the “existence of the soul” to the “workings of the law of karma”.

Some of these debates happened in front of a panel of judges (madhyastha), usually led by the royal who was paying for the whole exercise. There was a proposition and one side would make the case for (pakṣa) the motion and another side against (pratipakṣa), with the judges declaring when one side is finally defeated. Part of the text appears to be a distillation of these rules (nyāya) of debate in that somewhat formal context.

Types of Debates

Let’s start with a classification of the varieties of debates that we encounter. This classification is not based on the topic under discussion, but the attitude of the interlocutors. The verses (1.2.1–1.2.3) list out three kinds of debates. I like to think of these as more points on a scale than strict categorization.

  1. vādaḥ — An honest debate with each both sides attempting to discern the true nature of the subject under discussion. The rare ideal case.
  2. jalpaḥ — A tricky debate, where either side may use deceptive tactics to help them win. These tactics may keep both parties engaged in discussion, but it doesn’t help us get any closer to the truth of the matter under consideration.
  3. vitaṇḍā — A destructive debate, where the only goal of the opponent is to destroy the other person’s argument without attempting to establish an alternative proposition. This pretty much sums up every prime-time TV news debate nowadays.

While the extremes are easy to recognize, a tricky debate is harder to identify, because the tricks may be subtle. Which is why the text lists out these tricks in meticulous detail. Gautama apparently noticed way back then what Buzzfeed realized today — that people freaking love lists of things!

The most common class of tricks I’ve come across is quibbling (chala) — like arguing over the syntax when the meaning is clear from context, exacerbating a relatively minor flaw or taking a metaphor literally (1.2.14). There’s also the futile objections (jāti) — like an objection that presupposes their proposition (5.1.21), objecting to the absence of evidence as evidence of absence (5.1.29) or engaging in whataboutism (5.1.43). Finally, there’s the confounding and contradictory tactics that are an occasion for direct disqualification (nigrahasthāna) — like shifting the proposition (5.2.3), making incoherent arguments (5.2.10) or literally running away from the debate (5.2.20).

Anatomy of an Argument

To make this more relevant to current times, I’ll consider the example of global warming — which I mostly consider to be true. This article isn’t meant to provide a balanced view of the evidence for and against climate change and I’m just using it as an example for illustrative purposes. To start off, we need to establish the parts of an argument. The below sutra mentions 5 members.

pratijñāhetūdāharaṇopanayanigamanāni avayavāḥ (1.1.32)

  1. pratijñā — The proposition to be established. The planet is warming because of the burning of fossil fuels.
  2. hetu — The reasoning behind the proposition. Burning fossil fuels emit carbon dioxide.
  3. udāharaṇa — An example of a familiar instance. Carbon dioxide buildup in an outdoor greenhouse causes the temperature to rise.
  4. upanaya — An application of the reasoning to the example. Burning fossil fuels causes an atmospheric carbon dioxide increase similar to that simulated in a greenhouse.
  5. nigamana — The conclusion of the argument; usually just a restatement of the proposition. Burning fossil fuels cause the planet to warm.

This looks like a pretty straightforward inference schema. If you think this feels a little over-specified, you are not alone. Later Buddhist philosophers also pointed this out and preferred fewer steps in the establishment of an argument. Anyways, nothing wrong with erring on the side of more rigor.

Once I’ve established my argument, my opponent could then start objecting to the truth in each of my claims (is global temperature really rising?) and I would present additional supporting arguments (tarka) or refute their objections. This brings us to a very pressing question in current times, what qualifies as “the truth”?

Theory of Knowledge

The Nyaya school emphasizes belief in objective truth and lays out the acceptable means of knowledge or proof (pramāṇa) to realize that truth. The below sutra deals with a basic epistemological classification.

pratyakṣānumānopamānaśabdāḥ pramāṇāni (1.0.3)

  1. pratyakṣa — Direct sensory perception of the object. Observing regular temperature readings over a prolonged period.
  2. anumāna — Deductive inference based on cause (pūrvavat) and effect (śeṣavat) or a generalization (sāmānyatodṛṣṭaṃ). Rising temperatures cause more ice to melt which can be observed by measuring the size of polar ice caps.
  3. upamāna—Comparison to a similar thing. Comparing the effects of carbon dioxide buildup in the earth’s atmosphere to the conditions inside a greenhouse.
  4. śabda — Testimony of reliable sources. Citing articles from peer-reviewed journals.

Preferring a more minimalist approach, Buddhists only accepted perception and inference as valid means of knowledge. But, their theory of inference was pretty advanced and also covers the remaining two categories as special cases of inference. The Charvakas interestingly did not accept anything but direct perception as the only “true” means of knowledge and although they did accept inference as a useful tool, they also considered it a source of errors.

The most contentious point, however, was what classified as a “reliable” source. Vedic scholars considered the Vedas to be reliable. Similarly, with Buddhists and the teachings of Buddha. The Charvakas, being hardcore skeptics, considered none of these reliable. Given the recent internet-fueled rise of “fake news” and “filter bubbles”, I’d say humans aren’t much closer to solving this problem today than we were a couple of millennia ago.

Fallacious Reasoning

It’s become increasingly fashionable of late to memorize long lists of logical fallacies and call people out on them when debating. Turns out that this isn’t an entirely new phenomenon. The below sutra contains a list of logical fallacies (hetvābhāsa) to watch out for in an argument.

savyabhicāraviruddhaprakaraṇasamasādhyasamakālātītāḥ hetvābhāsāḥ (1.2.4)

  1. savyabhicāra — An argument that is too general and doesn’t establish any particular proposition or supports multiple propositions. Global warming is not caused by fossil fuel emissions because no climate model is perfect.
  2. virudh — Reasoning that contradicts the proposition to be established. The planet isn’t warming because temperatures are rising very slowly.
  3. prakaraṇasama — Circular reasoning. Global warming is not caused by fossil fuel emissions because fossil fuel emissions don’t cause global warming.
  4. sādhyasama — An argument that makes unsubstantiated claims. Global warming isn’t a thing because the planet is actually cooling.
  5. kālātīta — An argument that may have been valid in the past, but is no longer true. Humans are not causing global warming because human activity does not produce a lot of greenhouse gases.

This list is similar in function to the list of futile objections (jāti), in that they could be used to refute the opponents reasoning. Having a common vocabulary and shared understanding between the participants as to what these terms meant would have certainly helped all parties.


This text was by no means unanimously accepted and different schools of thought had different rules. Several Buddhist philosophers wrote scathing commentaries (famously Nagarjuna’s vaidalyaprakaraṇa) on the nyāyasūtra, attacking several core theses in a systematic manner — like a pre-modern philosophical diss-track. And, like any living tradition, the form and structure of these debates evolved over time. Nonetheless, it was interesting to consider the relevance of an ancient text to modern times.

Although the medium of interaction has undergone radical change, the people we interact with have not changed much. Keep a printout of this article in your back pocket for the next time you end up in an argument with someone and need some tips on how to proceed.