The word Lokayata occurs only once in the Arthashastra (PDF here), but it is a very significant mention. The treatise opens with the line “Om, salutations to Sukra and Brihaspati” the two progenitors of materialism and deha-vada (doctrine of the body as soul) in Vedic mythology. There are also numerous mentions of the “school of Brihaspati” later on in the text; though it is ambiguous which school Kautilya is referring to. Kautilya’s mention of Lokayata is as follows:
“Anvikshaki comprises the Philosophy of Sankhya, Yoga, and Lokayata… Righteous and unrighteous acts (Dharmadharmau) are learnt from the triple Vedas; wealth and non-wealth from Varta; the expedient and the inexpedient (Nayanayau), as well as potency and impotency (Balabale) from the science of government.
When seen in the light of these sciences, the science of Anvikshaki is most beneficial to the world, keeps the mind steady and firm in weal and woe alike, and bestows excellence of foresight, speech and action.” (1)
In light of this verse, it is certain that some of Lokayata was incorporated into the Arthashastra, but without the original source texts it is almost impossible to discern which parts.
To address a prominent, but contrasting view: Ramkrishna Bhattacharya denies this connection, and asserts that Lokayata was a purely lower class phenomenon. He makes the claim that the Brihaspati to whom Kautilya refers is not same as the alleged founder of Lokayata named Brihaspati. (2) However, there is no reason to imagine a new Brihaspati to explain this verse. That another thinker shared the name of Lokayata’s founder, adhered to materialism, and rejected the Vedas as tools of Brahmins is too great a coincidence to be accepted.
It is more logical that some Lokayatas (probably those in the upper class) simply dropped their anti-clericalism and metaphysical/epistemological speculations in order to work for Brahmins and kings. We can see this progression by examining third party descriptions. Ajita Kesakambali (C. 550 BC) was the last Lokayata (or proto-Lokayata) to most likely lack a theory of politics. (3) After him, references to Lokayata and politics, agriculture, or economics in the same sentence become more common. This also resolves the debate between David Rhys and Tucci regarding if Lokayata was the study of nature lore or politics. It probably comprised both, with different emphasis depending on the time period and social class of the practitioner.
As Warder says of Kautilya’s Arthashastra: “His system might therefore be described as eclectic or pragmatic: it is not pure Lokayata but applies Lokayata more than any other method” (4) Now under the wing of royal protection, Lokayata as a component of Arthashastra, survived in comfort and influenced the culture and policies of states which adopted the Arthashastra as a guide.
There is the distinct probability that the ontology of Lokayata influenced the astronomer and mathematician Aryabhata (born 476 CE). (5) Aryabhata adhered to a system in which the universe was made of four elements, earth, water, fire, and air. (6) Of all the extant systems of that time Lokayata was the only one, which accepted only four elements. (7)
According to Al Biruni‘s translation of his main text, Aryabhata also said, “That which is not reached by the perception of the senses and that which is not reached by perception is not knowable,” which coincides precisely with Lokayata epistemology, and none other. (8) It also makes sense that Aryabhata was not a member of the Hindu orthodoxy, as his findings contradicted Brahminical beliefs about cosmology. Brahmagupta wrote that “[The view] expounded by Aryabhata…and others is spearheaded against commonly accepted ideas… and alien to the Vedas, Smritis and Samhitas. The Samhitas, which were drawn up by Garga and others, say that Rahu is the source of the eclipse…” (9)
This is not to claim that Aryabhata was in fact a materialist. He does after all begin his chapters with invocations to Brahman. But his system does seem heavily influenced by them. As a highly influential scientist in ancient Indian, Arabic, and European astronomy, it goes without saying if Lokayata had impact through Aryabhata, it was immense.
Ayurveda is steeped in Vedic philosophy and its texts are heavily laden with theistic language. (10) Charaka’s logic relies heavily on the practice of dividing things into similar and dissimilar categories, a practice that seems to originate in Vaisheshika, not (directly) from Lokayata. (11) However, there is also reason to believe that the theism of the text was originally quite nominal, and that the relationship between early Ayurveda and the materialists was strong.
Though uncompelling on its own, we find a regional affinity between Lokayata, Tantra, Samkhya and Ayurveda, with all of them being strongest and/or originating in the northeast. Susruta was from Bihar. (12) However, there are stronger pieces of evidence available. Physicians in ancient India also seem to have been somewhat despised, or at the very least excluded by the religious elite. Manu Smriti, when talking about food, which is impure for a Brahmin to eat, says “The food of a doctor is pus” and “is not to be eaten”. If it is eaten unintentionally, “a three-day fast (is required)” (13) and if intentionally a “painful (vow)” is required. They were also prohibited from making offerings to the gods or ancestors. (14) If a twice-born male took medicine, he would become impure as long as it was in his body. (15) (16) A likely cause of this was that doctors had to violate the Vedic injunctions against handling corpses in order to preform dissections. On this subject the Sarirasthana reads as follows:
‘The different parts or members of the body as mentioned before including the skin, cannot be correctly described by one who is not well versed in anatomy. Hence, any one desirous of acquiring a thorough knowledge of anatomy should prepare a dead body and carefully, observe, by dissecting it, and examine its different parts.” (17)
No doubt physicians also incurred ritual impurity for touching bodily fluids such as menstrual blood, feces, etc.
Additionally, the parts of the Caraka-Samhita which actually deal with medical treatment are remarkably materialistic. This is particularly noticeable in regards to Karma. It does not mention the effects Karma as a medical consideration, which was contrary to orthodox beliefs at the time. (18) Nor is there any mention of appeasing Vayu, which was supposed to ensure freedom from disease. (19) Instead the causes of disease are ascribed to individual characteristics of the patient, which are fundamentally rooted in their guna or dosha compostion (similar to the greek humor system.) (20)
1- Kautilya, Kautilya’s Arthashastra, 9.
2- Bhattacharya, Studies on the Carvaka/Lokayata, 25-27
3- Dakshinaranjan Shastri, A Short History of Indian Materialism, Sensationalism and Hedonism, (Calcutta: Bookland Private LTD, 1930) http://www.scribd.com/doc/77452327/A-Short-History-of-Indian-Materialism-Sensatinalism-and-Hedonism-Dakshinaranjan-Shastri (accessed October 27, 2013), 28-29.
4- A.K. Warder, “On the Relationships between Early Buddhism and Other Contemporary Systems,”Bulletin of the School of Oriental and African Studies, 18, no. 1 (1956): 44, http://www.jstor.org/stable/610128 . (accessed October 27, 2013).
5- ed. B.S. Yadav, and Man Mohan, Ancient Indian Leaps into Mathematics, (New York: Springer, 2010), 88. Electronic edition
6- G.M. Bonard-Levin, “Aryabhata and Lokayatas,” Annals of the Bhandarkar Oriental Research Institute, 58/59 (1977-1978): 72, http://www.jstor.org/stable/41691679 (accessed October 25, 2013).
7- Note: There is the possible exception of Buddhism, but they were moving towards seven element models by this time.
8- Bonard-Levin, “Aryabhata and Lokayatas,” 73.
9- Bonard-Levin, “Aryabhata and Lokayatas,” 75.
10- Ray, A History of Hindu Chemistry From the Earliest Times to the Middle of the Sixteenth Century, xv- xvii
11- Debiprasad Chattopadhyaya, Science and Society in Ancient India, (Calcutta: Quality Printers and Binders, 1977), 150.
12- Marios Loukas, Alexis Lanteri, Julie Ferrauiola, R Shane Tubbs, Goppi Maharaja, Mohammadali Mohajel Shoja, Abishek Yadav, and Vishnu Chellapilla Rao, “Anatomy in ancient India: a focus on the Susruta Samhita,” Journal of Anatomy, 217, no. 6 (2010): 646-650, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3039177/ (accessed October 27, 2013).
13- Manu, The Laws of Manu, trans. Wendy Doniger, and Brian K. Smith (London: Penguin Books, 1991), chap. 4 v.220-222.
14- Manu, The Laws of Manu, trans. Wendy Doniger, chap 3 v. 152.
15- Manu, The Laws of Manu, trans. Wendy Doniger, chap 11 v. 154.
16- Manu, The Laws of Manu, trans. G. Buhler, (Oxford: Clarendon Press, 1886) https://ia700600.us.archive.org/6/items/lawsofman00manu/lawsofman00manu.pdf (accessed October 27, 2013), chap. 11 v. 154.
17- Marios Loukas et al., “Anatomy in ancient India: a focus on the Susruta Samhita.”
18- Chattopadhyaya, Science and Society in Ancient India, 190-200.
19- Chattopadhyaya, Science and Society in Ancient India, 264
20- Sarah Khurshid Khan, South Asian and Chinese Medical Systems: Ayurveda and Traditional Chinese Medicine Treatments for Diabetes Mellitus, Type 2. (PhD diss., The City University of New York, 2006), 95, http://books.google.com/books?id=PE6PVxd9SKMC&lpg.