Sunday, February 7, 2010

Logic Lecture Feb 8: Gautama and the Nyaya Sutra

BCC Logic
Eric Gerlach

Lecture on Gautama and the Nyaya Sutra

Gautama and the Nyaya School of Debate

Medhatithi Gautama, who lived sometime about 550 BCE, is considered the founder of the Nyaya school and the author of the Nyaya Sutra, a textbook and manual on logical debate. The Nyaya Sutra was not the first Indian text concerned with logical argument and analysis, but it became one of the most popular and thus foundational for the Nyaya school. It is believed that the Jains and Buddhists, who are more skeptical thinkers about logic but very involved in debate, later took much from the Nyaya Sutra and school. Nyaya means “right”, “just”, “justified” or “justifiable”, the same way we use ‘logical’ to mean ‘right debate or speech’. The school reached its height in 150 CE, but it traces itself back to Gautama and his teachings.

Gautama is also called ‘Akshapada’, ‘Eyes in the Feet’, from a legend that he was so deeply absorbed in thought one day on a walk that he fell into a well, and God (Brahma) gave him eyes in his feet to prevent this from happening again. Notice that, like the Vaisheshika ‘particular’ school, Nyaya is concerned with putting particular things into categories and relationships. Objects and substances can be called the ‘feet’ of things, and their families or causes (generalities) the head or mind of things.

The Buddha, who also lived sometime around 550 BCE is also called Gautama or Gotama. Some scholars used to argue that Gautama may have been the Buddha himself, but in fact they were two different founders of two different schools who were both from the Gautama region in Northern India which is how they share the name. Gautama, Buddha and Mahavira (the founder of Jainism), were also of the warrior caste, the second class in the Indian caste system beneath the first class Brahmins, the Vedic priests and scholars. This shows that the period produced new thinkers with new ideas that were questioning the established Vedic tradition, and the schools of this period are known to have become very popular because they were open to people of all castes including the lowest. A story from the period says that a scholar who gave up on the Vedas and turned entirely to logic turned into a Jackal. This story was obviously told by Vedic scholars and priests who found the new systems a threat to the old established traditions. Like science in Europe, however, the new ways were gradually added to the old ways, until the new system was an old standard alongside the Vedic traditions.

The Nyaya Sutra is one of many debate manuals that was written for Indian philosophical or cosmological debates. Questions asked included: “Is the self/soul/mind eternal or temporary?”, “Is the world and its laws eternal or temporary?”, “Is it better to renounce or indulge in luxuries?”, “Are there particular things which are sacred or is everything equally sacred?”, and, a question seen last week in Kanada’s text, “Is sound (and thus the oral tradition of the Vedas) eternal or temporary?”. This last question is central to the Nyaya text and Gautama’s form of proof that we will study.

It is noticeable that many of these debates are concerned with distinguishing the eternal from the temporary. In ancient world cosmology, the eternal was the sacred and the object of true knowledge. If one could determine which things and laws are eternal, one would grasp the ways of the cosmos.

Notice that these debates (vadas) are also all of the form: Is object X in group Y or group not Y? We will call this the Form of Nyaya Debate or Nyaya Vada. If one could justifiably claim that all Xs are Ys, one could then argue for further truths based on the established truths. Jains and Buddhists also took this form as fundamental. For instance, the Vedic priests argued that the self/soul/mind was eternal, while the Jains and Buddhists argued that it is temporary. In Greek thought, particularly with Plato and Aristotle, this arguing back and forth between opposite positions is called “Dialectic”.

Later, in Buddhist debates about 200 BCE, just after Nyaya hits its height, three areas of debate for a proposition were conducted in order: “Is X always Y?”, “Is X everywhere Y?” and “Is X Y in everything?”.

In ancient India, a king, authority or rich patron would organize a debate and banquet, invite participants from various schools of thought to debate (often the teachers of competing rival schools, like a competition in a Kung Fu movie). Women were not unheard of as debate participants, but not nearly as common as male debaters (one can unfortunately say this of American and British philosophical departments today).

Debate manuals like the Nyaya Sutra were designed to introduce students and scholars to typical forms of argument as well as methods of attack and defense. They also listed fallacies, types of false arguments that sound solid but have flaws. The Nyaya Sutra tells us that the best debater will not take cheap moves, ‘quibbles’ or ‘clinchers’, but one is free to make them at one’s own risk. The text is surprisingly honest and insightful on this point. By using deceptive reasoning, you could win the debate but you could also could lose if your opponent points out your errors or shortcuts. This is still true of argument today even in the most casual setting, and a good reason that looking into old Logic texts like the Nyaya Sutra is still useful today. Aristotle’s Organon, his ‘Tool’, are six books that cover different areas of debate and knowledge, similarly dealing with construction of argument and fallacies. Aristotle also must straddle the sometimes contrary goals of arguing truth and winning the debate.

The Nyaya Sutra and System

The Four Sources of Knowledge are Perception, Inference, Comparison, and Testimony. All of these can potentially give valid knowledge, but there are problems with each. Perception is seeing or experiencing something for oneself.

Perception can only be valid if it tells you something determinate that doesn’t vary or change. Two examples of false perception given in the text are confusing smoke and dust, and thinking that the hot earth is wet when in fact this is a mirage.

Inference is knowledge of an object produced by perception. This shows Induction of perception passing into Deduction of inference which is still held in Philosophy and Psychology today. There are two kinds of inference that one can have based on perception of associations (like rain always falling from clouds).

First, there is inference from perception of cause the knowledge of possible and potential effect. For example, if one sees dark rain clouds, one can infer that it may possibly rain. According to Kanada, Gautama and Modus Tollens (a basic form of Logic we saw first last week with Kanada), this is knowledge of a possibility, a potential, but not a certainty. If one sees clouds, it is wise to get ready for rain but it is not certain that it will rain.

Second, there is inference from perception of effect to knowledge of cause. For example, if one sees rain one knows there are clouds or if one sees a swollen river one knows that it must have rained. According to Kanada, Gautama and Modus Tollens this sort of knowledge is certain provided that one is not deceived. For example, if one sees smoke and it is not in fact dust then one knows that there is fire.

Comparison is knowledge of a thing by comparing it to something else that is similar or different. For example, if one knows that cows are mortal and temporary, one is quite justified in believing that horses, quite similar to cows in many ways, are mortal and temporary. Comparisons can often lead to valid beliefs, but there is the possibility of error. An example is believing wrongly that a horse has four stomachs because one knows this is true of a cow.

Testimony is instructive words from a reliable person or authority. There are two types, testimony of the perceived and testimony of the unperceived. The text gives the example of a physician saying butter makes you stronger as perceived and a priest saying you win over heaven with horse sacrifices as unperceived. Notice that, like Kanada’s text, this is a subtle attack on the older Vedic ways and suggests that they are uncertain compared to inferences drawn from perception. The Nyaya school is founded on the idea that valid deductive inferences must be based on regular and invariable perception, quite comparable to the modern scientific method.

The Form of Nyaya Proof

Some authors have claimed that Aristotle’s syllogisms are deductively valid but the Nyaya proof is not and based on induction. Actually, Aristotle has many syllogisms he admits are not deductively valid on their own and he also believes that one can only argue based on what one perceives and one can be mistaken exactly like the Nyaya School and Gautama. We can see induction and deduction working together in both Aristotle’s syllogisms and Gautama’s form of proof. As can see in the text, there are five steps but as the Buddhists correctly perceived the first and second are identical to the fifth and the fourth.

To make it easier, I have boiled it down to two steps. The first is a general rule backed by an example. The second step is a reason which leads to a conclusion. The text gives us an example:

Wherever there is smoke there is fire (rule), as in a kitchen (example).
Because there is smoke on the hill (reason), there is fire on the hill (conclusion).

For each of these parts, there are particular sorts of questions or doubts one can raise. If one is in a debate against an opponent, it is critical to know the sorts of doubts that one can raise against the opponent’s argument as well as the doubts one’s opponent can raise against one’s own argument.

The text gives us examples that can be used against its own example of proof. One can argue that an iron ball is on fire, but there is no smoke as a counter example to the rule “Wherever there is smoke, there is fire”, or one can argue that dust can be confused with smoke, so “There is smoke on the hill” may be misperception.
There is also two types of proof, positive homogeneous (proof by sameness) and negative heterogeneous (proof by difference).

Example of Proof By Sameness:
Whatever is produced is not eternal, as a pot.
Because it is produced, sound is not eternal.

Notice we saw this in Kanada’s text, and scholars have suggested it attacks the older Vedic tradition. The example above concerning fire on the hill is also a proof by sameness. This is quite similar to the structure of Aristotle’s most famous and basic syllogism:

If B, then C (plus example D), (If smoke then fire)
If A then B, then (if hill has smoke)
A then C (hill has fire)

Example of Proof By Difference:
Whatever is eternal is not produced, as in the soul.
Because it is produced, sound is not eternal.

Doubts, Fallacies and Quibbling

Doubt comes from five sources. There is doubt by sameness (ex: seeing in twilight, can’t tell bush or man), by difference (ex: seeing two men in twilight, and thinking still one is a tree), by conflicting testimony (ex: Hinduism says there is an eternal soul or self, while Buddhism says there is no eternal self or soul), by irregular perception (ex: one sees a horse with horns attached to its head and questions whether horses can have horns), and by irregular non-perception (ex: one sees a cow with its horns removed and questions whether cows can have no horns).

Fallacies are false arguments. Examples include changing the thesis, contradicting the thesis, meaningless utterance, incoherent speech (‘colorless sleep furiously green’ is a famous example by Noam Chomsky), repetition, silence, ignorance (failing to understand typically), evasion (‘I am called by nature’, ‘I have another appointment’), sharing the fault (problem with both sides), overlooking fallacies, pointing out false fallacies.

Quibbling is objecting to an argument as a fallacy when it is not actually a fallacy. Quibbling can lose a debate just as surely as giving a fallacious argument. The text gives three types: Term (ex: Someone claims to have a new (“nava”) blanket, but this is confused with the claim of nine (also “nava”) blankets), Genus (ex: Someone claims Brahmins are educated but the opponent objects that some Brahmins are two years old), Metaphor (ex: Someone claims poetically, “The scaffolds cry out”, and the opponent objects, “Impossible, they are inanimate objects”).