How do we know?

An introduction to Nyāya epistemology

Have you come across the following graphic on social networks?

This interesting visualization depicts how discrete data is categorized and connected to arrive at knowledge. But is knowledge just a connection of information? And if not this, what is knowledge? What is the nature and scope of knowledge? Philosophers have been deliberating on these questions for centuries. There’s a dedicated branch of philosophy to study knowledge known as Epistemology.

In Western Philosophy, knowledge has been defined as “Justified True Belief (JTB).”

According to the JTB theory, a subject S knows that a proposition P is true if and only if:

- P is true, and

- S believes that P, and

- S is justified in believing that P

However, Edmund Gettier challenged this theory with his seminal paper in 1963 to conclude that knowledge has to be more than justified true belief. Since then, we have seen several novel theories on the nature and origin of knowledge.

It’s no wonder that Indian Philosophy also has a centuries-long tradition of epistemological inquiry. Various schools propounded several theories related to reasoning, perception, conception, language, and justification that have been contested and debated by thinkers over the years. But it’s the Nyāya school that has done the most extensive and systematic work in epistemology (ज्ञानमीमांसा) and logic (तर्कशास्त्र).

Vācaspati defines the purpose of Nyāya as a critical examination of knowledge using the canons of logical proof. It has its origin in Nyāya Sūtra attributed to Akṣapāda Gautama composed in the third century BCE. Vātsyāyana made a detailed commentary on it in Nyāya Bhāshya. This was later followed by the work of Uddyotakara in Nyāyavārttika (sixth century CE) and Vācasapati’s Nyāyavārttikatāparyatīkā in ninth century CE.

What is knowledge?

According to Nyāya, knowledge can be valid or invalid.

Valid knowledge, called as Pramā (प्रमा), is assured (असंदिग्ध), true (यथार्थ), and presentative (अनुभव - presentative cognition) - असंदिग्धयथार्थ अनुभव ।।¹

Let’s unpack these terms.

1. Assuredness is conviction or firm belief in knowledge. There should be no doubt.

2. In Indian Philosophy, Prāmānyavāda (प्रामाण्यवाद) is the theory of apprehension of Truth. It consists of two views - Svataḥ Prāmānya (स्वतः प्रामाण्य) and Parataḥ Prāmānya (परत: प्रामाण्य) . In Svataḥ Prāmānya, the truth of knowledge is intrinsic. Knowledge is valid and true in itself and does not require any external validation. On the contrary, in Parataḥ Prāmānya, the truth or falsehood of knowledge depends on extrinsic conditions. The Nyāya school believes in Parataḥ Pramanya. Hence, for Naiyāyikas, knowledge has to agree with objective facts. As Satischandra Chatterjee puts it, to know a thing truly is to know it as characterized by its characteristics. We recognize a thing as a pot by its “potness.”

3. Valid knowledge is also presentative. It is the immediate apprehension of the object. Hence, we cannot consider memory as valid because it is representative knowledge and not presentative knowledge. The object of memory is not available for immediate apprehension.

Based on these conditions of validity, we can consider doubt and illusion as invalid (अप्रमा) knowledge.

Pramāna - The means of knowledge

So, we have some understanding of valid knowledge. But how do we get valid knowledge?

Indian philosophers have deeply contemplated this question. The means or source of valid knowledge is called as Pramāna (प्रमाण). And the Nyāya school considers four sources of valid knowledge - Perception (प्रत्यक्ष), Inference (अनुमान), Comparison (उपमान), and Testimony (शब्द).

प्रत्यक्षनुमानोपमानशब्दाः "प्रमाणानि" ||१|१|३||

Nyāya scholars analyzed each source through centuries in their expositions and commentaries. While it’s beyond the scope of this article to explore them in-depth, we can certainly begin with their overview.

Perception (प्रत्यक्ष)

Nyāya has defined Pratyaksha (प्रत्यक्ष) (Perception) as the knowledge gained through sense-object contact (इन्द्रियार्थसन्निकर्ष).

इन्द्रियार्थसन्निकर्षौत्पन्नं ज्ञानमव्यपदेशयमव्यभिचारी व्यव्सायात्मकं “प्रत्यक्षम्” ।।१।१।४।।

Perception is non-verbal(अव्यपदेश्य), should not deviate from its object(अव्यभिचार), and must be definite in character(व्यवसायात्मक). It is the primary source of knowledge that fulfills the criteria for validity. There’s no antecedent knowledge to perception. The Naiyāyikas classified different kinds of perceptions and defined various types of sense-object connections. We will have a lengthy discussion on perception in upcoming posts.

Inference (अनुमान)

Next, we have Anumān (अनुमान) (Inference), which means “after cognition/knowledge,” or knowledge/cognition that follows some other knowledge. Perception is antecedent to inference. You first need to perceive the phenomenon before determining its cause. For example, you see that there's smoke on the hill. Based on your prior experience, you can infer that there must be fire on the hill because of the smoke - “The hill is fiery because it smokes and whatever smokes is fiery.”

In this example,

• Hill is known as Paksha, the subject of inference (पक्ष)

• Fire is Sādhya( साध्य), or what is to be inferred

• Smoke is the reason or Hetu(हेतु) /linga

• The invariable relation between smoke and fire is known as Vyāpti (व्याप्ति). It proceeds from the previous knowledge of the relation between the major and the middle term.

  

Different Nyāya scholars have produced enormous literature on the analysis of Anumān. Hence, one can safely say that it was the favorite epistemological topic for Naiyāyikas.

Comparison (उपमान)

Upamān (उपमान) means similar cognition or cognition through comparison. The comparison is of properties between different objects. It is the relation between the object and its denotation. We cannot experience everything through perception or inference. Hence, Upamān offers a way to have knowledge through similarity between things. One can find a formal definition in Nyāya Sūtra:

प्रसिद्धसाधर्म्यात् साध्यसाधनम् "उपमानम्"।।१।१।६।।

Comparison is the knowledge of a thing through its similarity to another thing previously well known.

We can take a classic example to illustrate the concept of Upamān:

A man learns from a forest dweller that a wild cow is similar to a cow. He resorts to the forest, where he sees an animal like a cow. He recollects the comparison given by the forest dweller to conclude that the animal he sees is a wild cow.

The knowledge arises from the activity of the mind to fit the given description with an objective fact. It is qualified as a separate means to valid knowledge because it is different from perception, inference, and testimony. ²

Testimony (शब्द)

And lastly, we have Testimony as a valid means of knowledge. It is only valid when coming from a trustworthy person - somebody who has expertise in a specific matter.

आप्तोपदेशः "शब्द:” ।।१।१।७।।

You cannot trust a random tweet or a Whatsapp forward. You should receive it from somebody who is unbiased and has relevant experience in the subject. There are two kinds of testimony:

• that which refers to a matter which is seen

• that which refers to a matter which is not seen

The former is like a mechanic explaining the working of a machine, while the latter is like a spiritual person giving transcendental knowledge.

Testimony honors the centuries-long tradition of passing knowledge from teacher to disciple. While many will not consider it a valid means of knowledge today, it was a key knowledge source in ancient and medieval India.

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We have just scratched the surface in understanding the various means of knowledge in Nyāya epistemology. The interpretation and analysis of Pramānas are still an active topic in contemporary philosophy. We will understand each Pramāna in detail in the forthcoming issues.

1. The Nyāya Theory of Knowledge - Satischandra Chatterjee

2. ibid.