Ancient Indian Philosophy: A Painless Introduction

Ancient Indian Philosophy

A Painless Introduction

This is a short book about ancient Indian philosophy for people who care more about the central questions of philosophy themselves — What exists? How should we live? How can we know? — than they do about the historical matter of ancient Indian thought. But current research in philosophy often refers to the ideas of ancient Indian philosophy, so it is worth knowing a bit about it. My book explains the bare essentials about ancient Indian philosophy you must understand to do philosophy today.

This book does not assume you know much about philosophy. It does not discuss every aspect or interpretation of a philosopher’s work. It will only tell you what you need to know to engage with philosophy today. Luckily, that knowledge can fit on just a few pages.

My main sources are the historical works of Surendranath Dasgupta, Debiprasad Chattopadhyaya, and Satishchandra Chatterjee (of whom you will hear echoes below), along with translations of the original works.

Ancient India

No ancient culture but Greece was more fertile in philosophy than India. While Parmenides, Democritus, Socrates, Plato, and Aristotle were laying the foundations for Western philosophy in Greece, India’s geniuses produced treatises in linguistics, mathematics, logic, astronomy, philosophy, and medicine.

Unfortunately, one cannot write a history of Indian philosophy the way one can write a history of Western philosophy. In Western philosophy, particular individuals are known to have advanced certain views, and the historian may arrange each philosopher chronologically and comment on how each thinker responded to their predecessors and how they influenced later philosophers. But ancient Indian philosophy is represented in a mass of texts for which the authors and dates of composition are mostly unknown.

Chief among these texts are the Vedas, written from perhaps 1500-1000 B.C., the oldest religious texts in the world. They consist mainly of praise hymns to nature gods and instructions for ritual, and exemplify a primitive pre-theism. The latest works among the Vedas, the Upanishads, were written after 700 B.C. and are on occasion more philosophical. These Indian scriptures very loosely laid the foundation for most of India’s philosophical schools.

So early Indian philosophy is much foggier to us than is early Western philosophy. What, then, shall be our strategy? We will examine each major school of ancient Indian philosophy, and we will not speculate much about who influenced whom or when certain developments occurred.

Indians distinguish two classes of Indian philosophies: astika and nastika. The astika systems respect the Vedas to some degree. They are: Sankhya, Yoga, Vedanta, Mimamsa, Nyaya, and Vaisheshika. The nastika systems reject Vedic thought. They are: Jainism, Buddhism, and Lokayata. Though forms of most of these schools still exist today, I will write of them in the past tense to refer to their ancient forms.

In the West, philosophical schools tended to rise and fall, one after the other. But in India all these systems competed for adherents beside each other for centuries.

Each system (or darshana, literally “view”) eventually developed sutras: aphoristic summaries of its positions, along with quick responses to common objections and brief attacks on the other systems. But the systems themselves predate their sutras, probably by many centuries.


Except for the Lokayata materialists, all these systems agreed about karma and reincarnation. Karma means “action” and refers to the theory that humans will experience consequences (“the fruits of karma”) for their good and evil actions. When the fruits of karma cannot be experienced in the present life, the individual must be reincarnated — he must die and be reborn (as a human or another being) — to experience them.

Most Indian systems also agreed on the doctrine of samsara: that today’s humans have passed from birth to birth from eternity. The goal of these systems was moksha (or mukti): liberation from the endless cycle of birth and rebirth, and therefore liberation from all suffering.

Except for Buddhism and Lokayata, the Indian systems agreed on the existence of a permanent soul, or atman. In most systems, it was a kind of purification of the soul that lead to moksha, though what this means varied from system to system.

The Indian systems shared many ethical values, too. Generally, passions and desires were to be controlled, and harm was not to be done to any forms of life.

The Indian conceptions of space and time were vast. The past stretched back into infinity, or at least for billions of years. The Earth was but one of millions of worlds in an infinite universe. Accordingly, Indian thought emphasized the smallness of Earth, the insignificance of worldly possessions, and the transient nature of human life.

Perhaps most centrally, the ancient Indians did not see philosophy as a disinterested investigation of the nature of reality. Rather, philosophy was a practical matter: useful for daily life and in shaping one’s destiny.


Atheists and materialists were apparently common in ancient India, for the Hindu scriptures found it necessary to respond to the arguments of non-believers on many occasions. The materialist systems were often called “Lokayata,” which means “that which is found among people in general.”

Lokayata’s skepticism about karma, reincarnation, and theology came from its epistemology. Lokayata held that perception is the only valid source of knowledge, for all other sources like testimony and inference are unreliable. Perception revealed only the material world, made of the four elements: air, fire, water, and earth. Minds and consciousness were, too, the products of matter. Souls, gods, and the afterlife could not be perceived, and thus could not be said to exist. Religious rituals were useless, and scriptures contained no special insight.

Thus, the only purpose of life was to enjoy pleasure and avoid pain. Critics described the ethics of the Lokayata as egoistic, hedonistic, or even nihilistic.

Some Lokayata were accidentalists, in that they thought the world was ruled by chance: fire may come from fire or from flint, so there is no fixed cause-effect relation.

But most Lokayata were naturalists. They believed things moved and transformed because of their inherent natures, according to lawful necessity. Their fundamental principle was nature (svabhava).

The earliest known Indian materialist was Brhaspati, whose dates are unknown. He had no positive system to advance, but merely denied orthodox views of theology, ethics, and dualism. He said: “The whole Hindu system is a contrivance of the priesthood to secure a means of livelihood for themselves.” Because of him, earliest Indian materialism was sometimes called “Brhaspatya.”

Another early materialist was Ajita Kesakambali (6th century B.C.), who lived as an ascetic despite denying the afterlife, karma and morality. He was quoted as saying:

Ideas like generosity are the concepts of a stupid person. He who speaks of their existence, his words are empty and confused; a cry of desperation.

Later Indian materialism is sometimes called Carvaka after the supposed author of the Barhaspatya sutras, which are now lost.

One particularly interesting dialogue between an orthodox believer and a materialist was recorded in the Payasi Suttanta (6th century B.C.). In it, a materialist named Payasi denies dualism, reincarnation, and karma. An orthodox thinker, Kassapa, challenges Payasi to prove that those things do not exist.

First, Payasi says he has known some very evil men and some very good men, and he made them promise to tell him of their experiences if they died and were reincarnated. But many of them have died, and Payasi has not heard from any of them. So he doubts reincarnation. Kassapa replies that there might be keepers of the “other world” who do not allow reincarnated persons to tell anyone of their experiences. Kassapa concludes: “Be this exposition a proof to you… that [karma and reincarnation] exist.”

Next, Payasi says he knows many holy men who believe in dualism, reincarnation, and karma. But if they believe their life after death will be so much better than their life on Earth, why don’t they kill themselves? Kassapa replies that Payasi is foolish and evil, like a pregnant woman who cuts open her own belly to discover the sex of her child before it is born. Virtuous people have a reason for their Earthly life that Payasi cannot understand because he is foolish, Kassapa says.

Finally, Payasi suggests a way to test the theory of dualism. They could put a living man into a large jar and seal it with leather and cement, then put it in a fire so the man inside is roasted. Then they could take the jar out of the fire and uncover the top to watch the soul escape. If no soul escapes, then man has no soul. But this would prove nothing, says Kassapa, because souls are invisible.


The Jains replied to the Lokayata that if we are to reject testimony and inference because they sometimes mislead, then we must also reject perception because it, too, can mislead. So the Jains accepted inference (assuming that the rules of correct reasoning are followed), and they accepted testimony when it came from a reliable authority.

For the Jains, it was through perception that we know of the material world. But we also know the soul through inner perception, just as we perceive pain and pleasure by inner perception. Through inference we know consciousness cannot be material, for without consciousness matter alone could not be animated like living bodies are. And it was on the authority of all-knowing saints (tirthankaras) that the Jains claimed knowledge of spiritual matters.

The Jains held that there are souls in humans, animals, plants, and even in dust particles (perhaps an anticipation of microorganisms). Some souls are more conscious than others. Dust particles may have only a sense of touch, while men and higher animals have touch, sight, taste, smell, and hearing. But all souls are capable of consciousness. Unfortunately, the desires of souls attract tiny bits of matter that weigh them down. Only by removing its desires can a soul free itself from the bondage of matter and achieve happiness.

What can free a soul from its desires? Three things: faith in the teachings of Jaina saints, right understanding of these teachings, and right conduct. Right conduct consisted of abstinence from injury to life, from lying, from stealing, from sensual indulgence, and from attachment to earthly objects. When liberated from its desires, the soul may attain infinite knowledge, power, and bliss. This is the state achieved by the Jaina saints of the past, who led the way for others.

Though all Indian darshana stressed non-violence (ahimsa), this doctrine was most important to the Jains. Thus, the most radical Jaina might wear a mask to avoid inhaling gnats — not to avoid tasting a gnat but to avoid harming one. It was from the Jains that Gandhi inherited his insistence on non-violence, and from the Jains that many Hindu systems inherited vegetarianism.

Jains believed that Jainism had always existed, but the earliest historical figures to whom we can ascribe a Jaina philosophy are Mahavira (6th century B.C.). and perhaps Parshva (9th century B.C.).

Jainism was an atheistic view, like Lokayata and Buddhism.

As with Buddhism and the Hindu philosophies below, Jainism branched into an immense variety of religious worldviews, but in this short book we are only concerned with its ancient philosophical thought.


Siddhartha Gautama, later known as the “Buddha” (meaning “awakened one”), probably lived in the 5th century B.C. Along with Muhammad, Jesus and Confucius, the Buddha became one of the most influential thinkers of all time without writing any texts. Instead, his sayings and doctrines were compiled later by his disciples, who unfortunately disagreed with each other on some points, and thus it is difficult to reconstruct the views of the historical Buddha.

According to legend, Siddhartha was a prince who became dissatisfied with his life of luxury when he realized that every life eventually succumbs to sickness and death. After observing the joy of a compassionate monk, he renounced his princely life to seek a higher purpose. He tried extreme asceticism, but his health deteriorated, and he settled on a “middle path” between self-indulgence and self-abasement. Finally, he achieved enlightenment under a bodhi-tree, and set out to teach what he had learned.

Siddhartha criticized the Brahmin priests who accepted the Vedas out of faith and tradition. He said they were blind men leading the blind, one after another. He was also skeptical of doctrines that emotionally appealed to people, and knowledge that came from metaphysical speculation and theorizing. Such methods do not lead to anything near certainty, he said, and not even his own teachings should remain unquestioned.

He said the best way to know something was through personal experience. And where that is unavailable, one could consider what the wisest men say. But this may not be the only methods Siddhartha advocated, for early Buddhists often used inferential reasoning and philosophical meditation to attain knowledge, too.

Because our experiences are conditioned by emotion and limited by human ways of thinking, the Buddha was ultimately critical of all methods of knowing. All sources of knowledge were to be analyzed carefully.

He also put forth something like Pascal’s wager: if karma and rebirth are real, one’s actions have enormous consequences. If these doctrines are false, little is lost by ignorantly following them. So even though we cannot know whether karma and rebirth are real, it may be best to live in accordance with them anyway.

He agreed with Heraclitus that everything changes. Thus, there is nothing permanent, such as God or an eternal soul or even a persistent “self” — a persistent personal identity. But there is some continuity from life to life, following the law of karma, just as a tree spawns another tree through its seed.

Suffering lay at the core of Siddhartha’s philosophy. According to him, there was some suffering even in what appeared to be joy. But everything has a cause, and the cause of suffering is desire for worldly things, which causes us to be born into suffering again and again. If we understood that worldly desires cause suffering, we would not hold on to these desires. But we are ignorant. Liberation from suffering, the Buddha taught, comes through awareness of these truths and abstinence from worldly desire.

This philosophy was codified as the “four noble truths”: that there is suffering, that suffering has a cause, that there is an end to suffering, and that there is a path leading to the end of suffering.

The path to liberation was called the “eight-fold noble path”, and consisted of right view, right intention, right speech, right action, right livelihood, right effort, right mindfulness, and right concentration.

Right view was to accept the four noble truths. Right intention was to aim toward ridding oneself of wrong belief and action. Right speech was to avoid lies, divisive speech, abusive speech, and idle gossip. Right action was abstinence from killing, stealing, and sexual misconduct. Right livelihood was to avoid making a career of harm, such as business in weapons or meat or slave trading.

Right effort was persistent striving to abandon wrong thought, speech, and action. Right mindfulness was constant awareness of that which affects the body and the mind, including desire and emotion and thought itself. Right concentration was the practice of concentrating or meditating on something, which cuts off distractions and leads to self-awakening.

By these methods, the Buddha taught, one may reach a liberation from suffering into nirvana: a perfect peace of mind, free from desire — the end of identity due to a realized oneness with the world, perfect bliss and highest spiritual attainment.


Of the astika (Vedic) views, Sankhya appears to be the oldest. It was a dualist view based on two fundamentally different types of being: purusha (soul) and prakriti (matter, energy, and agency). Prakriti was the cause of the material world, but purusha had no cause. The soul did not change, but observed and enjoyed the ever-changing objects of prakriti.

Like a rope woven from three cords, the material world was woven of three gunas. They were inferred from the three ways we may react to things: with pleasure, displeasure, or indifference. Thus, the three constituents of prakriti were sattva (illumination, joy), rajas (excitation, pain), and tamas (roughness, obstruction, sloth).

According to Sankhya, a soul often confuses itself with its body. We feel pain upon the body as if it was pain upon the self, but this is a confusion. Once we realize the separateness of the soul, we cannot be affected by the joys and sorrows of the material world. But liberation does not result from propositional knowledge alone, but through spiritual training and deep meditation upon the truth that the soul is beyond the causes and effects of spacetime.

Sankhya had no need of God, for the material universe was sufficient to explain itself.

Sankhya is often credited to a Vedic sage named Kapila, whose dates are unknown. His philosophy had a major influence on other Indian darshanas, but disappeared as it was subsumed into Vedanta and Yoga.


The Yoga darshana, founded by Patanjali in the 2nd century B.C., accepted the metaphysics of Sankhya, but added God. God was a perfect, eternal, omniscient being, and the highest object of meditation.

The Yoga argument for God was as follows: Whatever comes in degrees must have a maximum. Knowledge comes in degrees, thus there must be a maximum of knowledge; omniscience must exist. The being with omniscience is called God.

But the more important addition to Sankhya was the practice of yoga: the cessation of all mental function. The correct practice of yoga included eight things:

  • Yama: restraint from violence, lying, theft, or avarice.
  • Niyama: building good habits like contentment, purity, Vedic study, and meditation on God.
  • Asana: good posture.
  • Pranayama: breath control.
  • Dharana: focused attention on an object.
  • Dhyana: meditation.
  • Samadhi: concentration so deep that self-awareness is lost.

According to Yoga, success in the practice of yoga led to a full realization of the gulf between purusha and prakriti, and therefore liberation from suffering.


Mimamsa was the darshana tied most closely to the Vedas. The purpose of the philosophy was to provide a method of interpretation that could harmonize and make sense of all the complicated rituals that were added to the Vedas during the many centuries of its composition, and also to provide a philosophical justification for these rituals.

The chief doctrines Mimamsa tried to justify were:

  1. The personal soul survives death and enjoys the consequences of the rituals performed on Earth.
  2. A certain force carries the effects of these rituals on Earth and into the afterlife.
  3. The Vedas are infallible.
  4. Earth is real and not a mere illusion.

Mimamsa apologetics began with epistemology, the method of knowing. Mimamsa acknowledged two kinds of knowledge: direct and indirect. Direct knowledge is had when one of the senses perceives something, and the sense organ is functioning correctly. But this tells us only that the object is, not what it is.

To know what the object is, we must interpret this direct knowledge. For this, we draw on past experience and logical inference to determine what classes the object belongs to, what qualities it has, and so on. Thus in the first stage we have knowledge of, say, redness with a particular shape. And in the second stage we process this perception through past experience and logical inference and, if our senses are working correctly and our inferences are sound, we correctly interpret the red shape as an apple.

But in addition to perception, Mimamsa admitted five other sources of knowledge: inference, comparison (noticing that two things have similarities), testimony, postulation, and (for some) “non-perception.”

Testimony was the most important after perception, for it was used to justify the infallibility of the Vedas. For Mimamsa, written or spoken claims gave us knowledge except when made by a known liar. And since, Mimamsa claimed, the Vedas are not known to lie, they may be taken as knowledge.

But Mimamsa usually revered the Vedas only for their commands about how to perform rituals, and thus they tried to ignore Vedic sentences that spoke of other things, such as what exists. Or, they tried to relate all such sentences to the commands about ritual. All knowledge in the Vedas was for the purpose of performing rituals correctly.

The Vedas were not held to be reliable because they were the words of God or of reliable prophets. According to Mimamsa, the Vedas were never written at all. They were an eternal part of the universe, and carry their own impersonal authority.

How did Mimamsa argue that the Vedas had never been written? First, they pointed out that its authors were not known. But more important was an argument of a Platonic nature.

A common view in some schools was that the sound of a spoken word was merely an instance of the real word (shabda), which is eternal. Why? Because if it were not so, then five different pronunciations of a word would mean that five different words had been spoken. But of course we know these pronunciations are merely imperfect copies of one word. So a word is not produced by its being spoken. And if it is not produced, then the real word must be eternal. Mimamsa then claimed that the Vedas consist of these eternal words, and the written or spoken Vedas are only pronouncements of the eternal Vedas. Thus the Vedas were not composed but are merely pronounced by humans.

This also explained why the Vedas are infallible. Since they were not composed by any person, they are not touched by any of the defects of fallible humans.

Concerning testimony in general, some schools replied that knowledge by testimony is really knowledge by inference, for the validity of testimony is determined by inference from the general reliability of such testimony. Mimamsa responded by saying that all knowledge is warranted by the conditions that generate that knowledge, and so testimony is no different: it provides knowledge when it is given in the right context.

As mentioned earlier, another source of knowledge for the Mimamsa was postulation. Here it was meant that we gain knowledge when some phenomenon can only be explained by postulating a certain explanatory hypothesis (arthapatti). Postulation, then, is an argument to the best explanation, except that an arthapatti was held to be the only possible explanation for some phenomenon, not merely the “best.”

Finally, we come to non-perception (anupalabdhi). This explained how we know that something does not exist before us. When I know that there is no cat sitting before me, it is not because of perception. It is not because I “perceive a non-cat.” It is because the cat is not perceived. Thus non-perception is an independent source of knowledge.

But here again, the conditions must be suitable for non-perception to work properly. We do not see a table in the dark, but that does not mean a table is not there. For non-perception to show us that a table is not there, we must have enough light to see that a table is not there.

According to Mimamsa, truth was self-evident, for it carried with it assurance about its own truth. Only when we are alerted to certain defective conditions for truth, or to contrary knowledge, can we infer the falsity of what at first seemed true. Belief should be default; doubt is unusual.

Against a Nyaya view that all knowledge ultimately comes by inference, Mimamsa replied that this leads to an infinite regress. If a perception provides knowledge only by inference, then that inference itself must be verified by another inference, and so on. To end this regress we must see that truth comes with its own warrant, given the proper conditions.

Mimamsa then argued that because perception and other methods give knowledge of things in the world, we can reject those views which say the world is an illusion. Moreover, the Vedas give knowledge of other things, such as souls, heaven, hell, karma, and gods who demand sacrifice and ritual.

What of ethics? In Mimamsa, the Vedas played the role that Almighty God plays in Western religions. Moral duties came from the Vedic commands. A good life was one obedient to the Vedas. And though the rituals and sacrifices commanded by the Vedas would bring blessing by the law of karma, obligatory actions were to be performed not from selfish motivation but because we had a duty to perform them, as in Kant.


The Nyaya school was founded by a man named Gotama with his Nyaya-sutra, but evolved greatly after that. Thus it is hard to take a snapshot of what Nyaya philosophy was at any one time, and this overview bleeds together elements of ancient and later Nyaya philosophy.

The Nyaya school’s chief concern was epistemology. What is correct thinking, and how can we come to know reality? Only when we know the answers to these questions can we achieve liberation.

How do we test if what we “know” corresponds to reality? The Nyaya, Vaisheshika, Jaina, and Buddhist schools said that true knowledge led to success in practical activity, while false knowledge led to failure and disappointment.

The standard illustration of this was a story about putting sugar in tea. Suppose you think the white powder in a jar is sugar, so you put a spoonful of it in your tea to sweeten it. Your tea tastes sweeter than before, so your belief that the white powder was sugar has been confirmed. But let us say you put some of the powder in your tea and now it tastes bitter! Your belief that the white powder was sugar has been disproven — it was salt all along!

According to Nyaya, there were four valid sources of knowledge — perception, inference, comparison, and testimony — and also four sources of invalid knowledge: memory, doubt (when there is no definite mark that would distinguish the truth from illusion), error (false certainty), and hypothetical argument (“If there was no fire, there wouldn’t be smoke, but there is smoke, so there must be fire”).

Perception was an unerring belief produced by contact between an object and the senses. When I have clear and certain sight of a table, this is perception, and valid knowledge. If I see a shape in the distance that could be a man or a post but I cannot tell which, this is doubt, and not valid knowledge. If I am certain that I see a snake in a coil of rope, but there is no snake, this is error.

But Nyaya, perhaps even more-so than the other schools, was a system open to vicious internal debates. Some Nyaya adherents said that perception does not require contact between an object and the senses. God, for example, perceives all things but has no senses. So perception really is just an immediate awareness of something in the mind that does not call upon previous experiences or any reasoning process, such as inference.

Inference, then, was knowledge that followed from some other knowledge: “Gotama is mortal, because Gotama is a man, and all men are mortal.” Each case of inference has at least three propositions and, as in Aristotle’s logic, a minor, major, and middle term. Here, Gotama’s manhood is the minor term (paksa), for it is the subject we are considering. Gotama’s mortality is the major term (sadhya), for it is that which we want to establish by means of inference. The mortality of all men is the middle term (linga), for it is what grounds our inference from Gotama’s manhood to his mortality. Also as in Aristotle’s logic, each proposition in Nyaya inference was categorical.

However, most Nyaya adherents preferred to state these categorical syllogisms in five propositions, like so:

  1. Gotama is mortal;
  2. Because he is a man;
  3. All men are mortal, for example Siddhartha, Brhaspati, and Kapila;
  4. Gotama is also a man;
  5. Therefore Gotama is mortal.

First, the conclusion is asserted. Second, the reason for the conclusion. Third, the universal proposition is given, which connects the conclusion with the reason given, supported by known instances. Fourth, we apply the universal proposition to the present case. Fifth, the conclusion is restated.

The ground of inference involved a correlation between two things, for example mortality and manhood. Nyaya said that the one pervades the other, in that it always accompanies the other. Mortality pervades manhood; manhood is pervaded by mortality. But manhood does not pervade mortality, for many things are mortal without exhibiting manhood. A fish is mortal but it is not a man.

But how do we justify the universal proposition? How do we know that all men everywhere are mortal? This is the problem of induction. Vedanta defended induction by enumeration. When we always experience two things together (“swan” and “white”), we can take them to be universally related. When we discover there are black swans in southern Australia, well… we were wrong.

Nyaya required more than this to justify induction. They said that in addition to an agreement in presence between two things (“where there’s smoke, there’s fire”), there must also be an agreement in absence (“where there is no fire, there is no smoke”). This agrees with John Stuart Mill’s “joint method of agreement and difference.”

Third, Nyaya said we must also be careful to eliminate any conditions (upadhis) on which the apparently universal agreement in presence and absence depends. If I flip the switch there is light, and if I don’t then there is none. But I make a mistake if I infer there is an invariable relation between flipping the switch and lighting the room, for I have ignored an important condition: electrical current. If there is no electrical current, flipping the switch and producing light will no longer be invariably related.

Still, skeptics like the Lokayata and David Hume would press that we still can’t know whether such relations will hold in distant places or into the future, and Nyaya admitted that induction from particulars was not foolproof. In fact, said Nyaya adherents, there are degrees of certainty in induction. We are more certain that all men are mortal than that all crows are black, for there does not seem to be anything in the nature of crows that compels them to be black, but there does seem to be something in the nature of manhood that compels men to be mortal. This “seeming” was, according to Nyaya, a special kind of direct perception about the class-essences of mortality and manhood.

After perception and inference, the third form of valid knowledge for Nyaya was comparison (upamana). This was the knowledge of what a word denotes. A young girl who does not know what a jackdaw is may be told it is like a crow, but bigger and of grey and black color. If she later encounters a bird like a crow but bigger and of grey and black color, she may think, “This must be a jackdaw,” and she would know this by “comparison.”

The final source of valid knowledge for Nyaya was testimony, which consisted of understanding the meaning of what is said by a trustworthy person. But this required an analysis of what a sentence is, and how it can be understood.

For Nyaya, a sentence was a group of words, carefully arranged. A word referred to an object. This reference was called its potency (sakti), and its potency was due to God. In order for words to be arranged successfully into a sentence, their arrangement must meet four conditions: expectancy, mutual fitness, proximity, and intended meaning.

Expectancy referred to the fact that some words “expect” others. When I say “bring,” you ask: “Bring what?” The word “bring” needs an object in order to make sense.

Mutual fitness required that the words of a sentence not contradict each other. The sentence “Wet the food with fire” fails because “wet” contradicts “fire.”

The words of a sentence also needed correct proximity. To speak the sentence “Bring a cow,” it will not work to say “bring” on March 1st, “a” on March 5th, and “cow” on March 12th — even if those are the only words you say in the month of March, and even if the other conditions are met.

Whether a sentence succeeded also depended on its intended meaning. The sentence “Bring a bat to the party” can only succeed if we first ascertain which meaning of “bat” was intended by the speaker: a wooden play-tool or a flying mammal.

Using these sources of knowledge, what did Nyaya say about the physical world? Like some ancient Greeks, they said the world is made of eternal atoms of earth, water, fire, and air.

What of the self? Lokayata said the self was the living body plus consciousness. Buddhism said the self was only a stream of thoughts. Vedanta said the self was Brahman, the One. For Nyaya, the self was a unique thing with its own thoughts, feelings, desires, and volition. Each body had its own self, for each body had its own thoughts, feelings, desires, and volition. Moreover, each self was eternal.

The self could not be merely the body, for the body by itself is unconscious. It could not be the senses, for these cannot account for imagination. It could not be a stream of thoughts, for this would not explain memory. But neither was the self Brahman, for each self has its own thoughts, feelings, and desires that are not shared by other selves.

When one achieved true knowledge of the world and the self, one could achieve liberation from pain. When one realized that the self is separate from the body, one could be liberated from the body, and therefore from all the pain and pleasure that comes to the self through it.

What of God? God arranged the world from the eternal atoms, space, time, ether, and souls. God was all-powerful, all-beautiful, all-knowing, perfectly moral, and perfectly free from attachment.

The first argument for God’s existence was a causal argument: many objects in the world are limited and made of parts, and thus must be the effects of some intelligent cause. Without an intelligent cause, they could not bave been so ordered and coordinated. But unlike Western natural theology, Nyaya did not invoke God to explain the existence of things, for atoms are eternal. They only invoked God to explain the order of things.

Nyaya also asserted an argument from delayed karma. This took the law of moral cause and effect for granted, but noted that there was often a delay between good action and reward, or a delay between bad action and punishment. A youthful sinner may suffer infirmity only in old age. How does the “merit” and “demerit” produced by good and bad actions affect our lives so many years later, and how do they produce the proper effects? Only an intelligent agent that has knowledge of all these merits and demerits could guide the force of karma to produce the proper effects.

A third argument concerned the authority of scripture. The Vedas were taken to be authoritative by all the astika schools. How could we explain this? Their authority must come from the fact that the Vedas were written by an omniscient God.

Unfortunately, a short book like this one must pass over many aspects of Nyaya epistemology and theology.


Vaisheshika was founded by Kanada in the 2nd century B.C. It agreed with Nyaya that suffering was caused by ignorance, and liberation was achieved by the right knowledge of reality.

Vaisheshika mostly agreed with Nyaya about epistemology, though it recognized only two sources of knowledge because it reduced comparison and testimony into perception and inference.

It focused its study on six categories or padartha of knowledge: substance, quality, activity, generality, particularity, and inherence.

Vaisheshika said substance is the stuff in which a quality or action can exist. There are nine primary substances: earth, water, light, air, ether, time, space, soul, and mind.

The first four substances are made of four distinct kinds of atoms: earth, water, light, and air. We can infer atoms like so: Ordinary objects are made of parts. But if we separate the parts of a thing, we pass from larger to smaller to still smaller, and so on. But this cannot continue forever, so we must eventually arrive at tiny atoms that cannot be divided. These atoms must be eternal. To produce something is to arrange parts in a certain way, and to destroy something is to break it up into its parts, but atoms have no parts, so they cannot be produced or destroyed.

Ether is the substance in which sound is a quality. Sound cannot be a quality of earth, water, light, or air because sound can be perceived in the absence of these substances. (This is of course a mistake, for sound cannot be heard in outer space.)

Space is inferred from our thoughts about “here” and “there” and “near” and “far.” Time is inferred from our thoughts about “past” and “present” and “future.”

Soul is an eternal substance in which consciousness is a quality. There are two kinds: the individual soul and the supreme soul. The former is internally perceived, and inferred from thoughts like “I am happy.” There is but one supreme soul, which is inferred to be the creator of the world.

The final substance is mind, which is inferred from our internal perception of things like thought, feeling, and volition.

After substance, the second category for Vaisheshika was quality. Vaisheshika said that all qualities must belong to substances and not other qualities. So the color red belongs to some thing but not also to another color.

Vaisheshika discussed 24 types of qualities: color, taste, smell, touch, sound, number, magnitude, distinctness, conjunction, disjunction, remoteness, nearness, cognition, pleasure, pain, desire, aversion, effort, weight, fluidity, viscidity, tendency, merit, and demerit. Within many of these, there are several subdivisions.

The third category was activity — physical movement — which must also belong to a substance. Vaisheshika said activity is the cause of the conjunction and disjunction of things. But there can only be activity in corporeal substances: earth, water, light, air, and mind. There can be no activity in all-pervading substances: space, time, and soul.

The fourth category was generality. This concerned the fact that many things possess a common nature. What is it that cows have in common? What is the “universal” (in Western terms) that they share?

The Buddhists were nominalists. They said only the individuals are real; universals do not exist. Certain four-legged animals are called “cow” not because they possess a common essence, but because we decided to call them that to aid in communicating about the daily matters of life.

The Jains were conceptualists. To them, the universal called “cow” did not point to an independent entity, but was constituted by the essential common attributes of all these individuals we call “cow.”

The Nyaya and Vaisheshika schools were realists about universals. They held that universals are eternal entities, distinct both from individuals and from the essential common attributes of those individuals.

The fifth category was particularity, the study of how we are to understand the uniqueness of things which have no parts. How can we distinguish one atom of light from another? How can we distinguish one mind from another? We can’t distinguish these by a difference in parts, for these things have no parts. The Vaisheshika named this peculiar character of part-less yet distinguishable substances vishesa.

The sixth category was inherence, a permanent relation between two entities, where one thing inheres in the other. A whole cow inheres in its parts, a quality or activity inheres in its substance, a universal inheres in the individuals, and particularity inheres in a part-less eternal substance.

Some later adherents to Vaisheshika recognized a seventh category of knowledge: non-existence. There were two types of non-existence. First, it is sometimes the case that one thing is not another thing. Second, it is sometimes the case that one thing does not inhere in another thing.

According to Vaisheshika, the Supreme Lord (Mahesvara) created and destroyed the world in a cycle that had no beginning and will have no end. The Lord directed the movement of the atoms and enforced the laws of karma. After the stress and pain of many lives experienced in the cycle of death and rebirth, the Lord eventually allowed escape from this misery by destroying the world. He later created a new world, and the cycle of rebirth, and therefore the cycle of pain, began anew.


The Vedanta school split into a greater variety of philosophies than any of the other astika (orthodox) systems, and its literature quickly became vast. Vedanta means “Veda-end” or “the appendix to the Vedas,” and the term originally simply referred to the Upanishads. Only in the Medieval period did the philosophies centered on the Upanishads begin to be called Vedanta as well.

Ancient Vedanta was codified into the Vedanta-sutra around 200 B.C., but its aphorisms were cryptic and this gave rise to the variety within Vedanta, each Vedanta school with its own interpretations.

Some of the most well-known schools of Vedanta — including Advaita Vedanta, Vishishtadvaita, and Dvaita — arose during the Medieval period, and are thus not covered in this book. But let us turn to ancient Vedanta.

The central doctrine of ancient Vedanta was Brahman: the eternal, uncaused, transcendent, Ultimate Reality; the ground of all being. God (Ishvara) was also important in Vedanta, though the Vedanta schools disagreed on whether God was Brahman, or was related to Brahman in some other way. They also disagreed as to whether the self was identical to or part of Brahman, or separate from Brahman, or — somehow — both identical and seperate from Brahman.

Some versions of this doctrine of Brahman, then, qualify as panentheism. (Pantheism says that God is identical to the world; panthentheism says that God contains the whole world but also exists beyond it.)

The goal of Vedanta was to discover the Real Self (unity, in some way, with Brahman) by controlling the “lower self” and its impulses through study and meditation. Only this realization could stop the cycle of rebirth and all its misery.

How was this unity between the self and Brahman to be explained? By analogy: Just as different items of gold are all really the same because they are all gold in different forms and with different names, so in all things and people there is the same reality, and their differences are only in the names we give them.

Beyond this, little can be said of ancient Vedanta, for its main surviving schools arose during the Medieval period.