The Cārvāka school is one of the nāstika or “heterodox” philosophies . It rejects ritualism and supernaturalism, emphasizes materialism (matter is the fundamental substance in nature, and that all things, including mental states and consciousness, are results of material interactions) and philosophical skepticism, holding empiricism, perception and conditional inference as the proper source of knowledge. Cārvāka is an atheistic school of thought. It holds that there is neither afterlife nor rebirth, all existence is mere combination of atoms and substances, feelings and mind are an epiphenomenon, and free will exists.
One of the widely studied principles of Cārvāka philosophy was its rejection of inference (anumāṇa) as a means to establish valid, universal knowledge, and metaphysical truths. In other words, the Cārvāka epistemology states that whenever one infers a truth from a set of observations or truths, one must acknowledge doubt; inferred knowledge is conditional.
Charvakas denied metaphysical concepts like reincarnation, an extracorporeal soul, the efficacy of religious rites, other worlds (heaven and hell), fate and accumulation of merit or demerit through the performance of certain actions. Charvakas also rejected the use of supernatural causes to describe natural phenomena.
Charvaka believed that there was nothing wrong with sensual pleasure. Since it is impossible to have pleasure without pain, Charvaka thought that wisdom lay in enjoying pleasure and avoiding pain as far as possible. Unlike many of the Indian philosophies of the time, Charvaka did not believe in austerities or rejecting pleasure out of fear of pain and held such reasoning to be foolish.
Charvakas were critical of the Vedas, as well as Buddhist scriptures. To Charvakas, the Vedas suffered from several faults – errors in transmission across generations, untruth, self-contradiction and tautology. The Charvakas pointed out the disagreements, debates and mutual rejection by karmakanda Vedic priests and jñānakanda Vedic priests, as proof that either one of them is wrong or both are wrong, as both cannot be right.
Carvaka declared the Vedas to be incoherent rhapsodies whose only usefulness was to provide livelihood to priests. They also held the belief that Vedas were invented by man, and had no divine authority. Charvakas rejected the need for ethics or morals, and suggested that “while life remains, let a man live happily, let him feed on ghee even though he runs in debt”.
Brihaspati is traditionally referred to as the founder of Charvaka or Lokāyata philosophy. Much of the primary literature of Charvaka, the Barhaspatya sutras, were lost either due to waning popularity or other unknown reasons. Its teachings have been compiled from historic secondary literature such as those found in the shastras, sutras, and the Indian epic poetry as well as in the dialogues of Gautama Buddha and from Jain literature. This reliance on indirect sources raises the question of reliability and whether there was a bias and exaggeration in representing the views of Charvakas.
Ājīvika is one of the nāstika or “heterodox” schools of Indian philosophy. Purportedly founded in the 5th century BCE by Makkhali Gosala, it was a śramaṇa movement and a major rival of Vedic religion, early Buddhism and Jainism. Ājīvikas were organised renunciates who formed discrete communities. The precise identity of the Ajivikas is not well known, and it is even unclear if they were a divergent sect of the Buddhists or the Jains.
Ajivika’s was an atheistic philosophy. They did not presume any deity as the creator of the universe, or as prime mover, or that some unseen mystical end was the final resting place of the cosmos. The Ājīvika school is known for its Niyati (“Fate”) doctrine of absolute determinism, the premise that there is no free will, that everything that has happened, is happening and will happen is entirely preordained and a function of cosmic principles. The Buddhist and Jaina sources describe them as strict fatalists, who did not believe in karma.
Ajivikas belief in predeterminism does not mean that they were pessimistic. Rather, just like Calvinists belief in predeterminism in Europe, the Ajivikas were optimists. The Ajivikas simply did not believe in the moral force of action, or in merits or demerits, or in after-life to be affected because of what one does or does not do. Actions had immediate effects in one’s current life but without any moral traces, and both the action and the effect was predetermined, according to the Ajivikas.
Another doctrine of Ajivikas philosophy, according to Buddhist texts, was their antinomian ethics, that is there exist “no objective moral laws”. There is neither cause nor basis for the sins of living beings and they become sinful without cause or basis. Despite this ascribed premise of antinomian ethics, both Jain and Buddhist records note that Ājīvikas lived a simple ascetic life, without clothes and any material possessions.
Original scriptures of the Ājīvika school of philosophy are currently unavailable and probably lost. Their theories are extracted from mentions of Ajivikas in the secondary sources of ancient Indian literature. It is therefore likely that much of the information available about the Ājīvikas is inaccurate to some degree, and characterisations of them should be regarded carefully and critically.
Several rock-cut caves belonging to Ājīvikas are dated to the times of the Mauryan emperor Ashoka (r. 273 BC to 232 BC). These are the oldest surviving cave temples of ancient India, and are called the Barabar Caves in Jehanabad district of Bihar.
Ajñāna is one of the nāstika or “heterodox” schools of ancient Indian philosophy, and the ancient school of radical Indian skepticism. It was a Śramaṇa movement and a major rival of early Buddhism, Jainism and the Ājīvika school. They have been recorded in Buddhist and Jain texts. They held that it was impossible to obtain knowledge of metaphysical nature or ascertain the truth value of philosophical propositions; and even if knowledge was possible, it was useless and disadvantageous for final salvation. They were specialized in refutation without propagating any positive doctrine of their own.
The Ajñana claimed that the possibility of knowledge is doubtful since the claims to knowledge were mutually contradictory.