India produced one of the richest philosophical traditions in the world, with centuries of debate on knowledge, logic, language, the self and liberation. Buddhism was one voice in that conversation; this level introduces others.

The Upanishads

The oldest Indian scriptures are the Vedas, collections of hymns and ritual texts. The Upanishads are philosophical texts attached to the end of the Vedas, which is why they are also called Vedanta, “the end of the Veda.” The oldest, such as the Brihadaranyaka and Chandogya, were likely composed in the first millennium BCE, before the Buddha.

They ask what lies behind the changing world and the changing self. Their central answer is that Brahman, the ultimate reality underlying everything, and Atman, the true inner self, are one and the same. In the Chandogya Upanishad, a father teaches his son Svetaketu by having him dissolve salt in water: the salt cannot be seen, but every sip tastes of it. So the subtle essence pervades everything, and the father repeats the phrase tat tvam asi, “that thou art.”

The Upanishads also develop ideas shared across Indian thought: samsara, the cycle of birth, death and rebirth; karma, action and its consequences; and moksha, liberation from the cycle through true knowledge.

The six orthodox schools

Classical Indian philosophy is often divided into schools that accept the authority of the Vedas (called astika, orthodox) and those that do not (nastika, heterodox). There are traditionally six orthodox schools, often grouped in pairs:

• Nyaya, focused on logic and how we know things, and Vaisheshika, which developed a theory of categories and atoms.
• Samkhya, a dualism of pure consciousness (purusha) and matter (prakriti), and Yoga, the practical discipline of meditation set out in Patanjali's Yoga Sutras.
• Mimamsa, focused on interpreting Vedic ritual and duty, and Vedanta, based on the Upanishads. Its best known form is Advaita (“non-dual”) Vedanta of Shankara (eighth century CE), who taught that only Brahman is fully real.

The heterodox schools include Buddhism, Jainism and the materialist Charvaka school, which rejected rebirth and held that only perception gives reliable knowledge.

Jainism and ahimsa

Jainism took its classic form with Mahavira, a contemporary of the Buddha, whom Jains regard as the twenty-fourth tirthankara, or “ford-maker,” a teacher who shows the way across the river of rebirth. Its central principle is ahimsa, non-harming of all living beings. Jain monks and nuns take great care to avoid injuring even insects, and Jains are traditionally vegetarian. Lay Jains take lesser vows of non-harming, truthfulness, not stealing, sexual restraint and non-possessiveness.

Jainism also teaches anekantavada, the “many-sidedness” of reality: any claim captures only part of the truth. The parable of the blind men and the elephant (found in several Indian traditions) illustrates it: one touches the trunk and says “snake,” another the leg and says “pillar.” Each is partly right.

The Bhagavad Gita

The Bhagavad Gita, “Song of the Lord,” is part of the great epic the Mahabharata. On the battlefield of Kurukshetra, the warrior Arjuna refuses to fight, because the opposing army includes his relatives and teachers. His charioteer, Krishna, revealed as divine, persuades him to act. Arjuna must perform his own duty (svadharma) as a warrior, but he should act without attachment to the fruits of action, doing what is right without craving reward or fearing loss. The Gita also describes paths of knowledge, action and devotion (bhakti).

Readers have debated it intensely. Some see it as endorsing war and fixed social roles tied to caste. Others, including Gandhi, read the battle as an allegory of inner moral struggle, and treasured it as a guide to selfless action.

Worked example: one decision, several Indian lenses

Imagine Ravi, a young doctor in a hospital, who is asked to work through a dangerous epidemic. He is afraid for himself and his family, and part of him wants to resign.

The Bhagavad Gita might speak to him most directly. Like Arjuna, Ravi faces a duty he is tempted to abandon. Krishna's advice would be to perform his svadharma, his own duty as a healer, but to act without attachment to the fruits: not for praise, nor in terror of failure, but because the work is right. Doing one's duty with a calm mind is itself a form of spiritual practice.

Jainism would ask how to minimize harm: to patients, to staff and to Ravi's own family. Ahimsa is not only a refusal to injure but an active care for all living beings.

Anekantavada would suggest humility. Ravi's colleagues who stay and those who leave for family reasons may each see part of the truth. Like the blind men and the elephant, each grasps a different side of a complex situation.

The Upanishads would offer a deeper frame: if Atman is Brahman, then the patients and Ravi share the same deepest self. Caring for them is, in a sense, caring for oneself.

A modern reader might note a problem with the Gita lens. In the epic, duty was tied to caste, and Arjuna's duty was set by birth as a warrior. Ravi chose his profession freely. Many modern readers, following Gandhi, keep the Gita's teaching on selfless action while rejecting duty by birth. That reinterpretation is itself part of the tradition's living history.