In ancient India the materialist sect was represented by the Charvakas sect. The sect is very old and was prevalent during the time of the historical Buddha, 563 BCE. It is really no philosophy having died out sometime shortly after the Buddha's passing.
The Charvakas rejected the idealism of the Upanishads. They accepted only four means of valid knowledge: earth, air, fire and water and that from these three we could understand the world and all its events. They did not accept inference as a valid means of knowledge. Brhaspati is the reputed founder of this sect. His Sutra is now lost but according to Sharma, we have no reason to doubt that it once existed.
In a nutshell, the name Charvaka signifies a person that believes in "eat, drink and be merry", or a person whose doctrine is superficially attractive. I must admit that when I first read about this sect, it seemed to make a lot of sense because it seemed so dirt simple. Later, after having read and contemplated real Indian philosophers I came to realize the superficiality of the metaphysics of materialism.
The materialistic sect of Brhaspati taught that perception is the only authority; the elements are the only means of epistemology or valid knowledge. Enjoyment is the only end of human existence; mind is only a product of matter. There is no other world; death means a simple liberation. Earth, air, fire, and water are the elements. Consciousness arises from matter and is the result of a combination of matter; the soul is nothing but the conscious body.
There is no heaven, no liberation, nor an individual soul-monad - nor do the actions of any rituals produce any real effect. If food given to the gods are enjoyable,then why not give it to the poor down below? How can a man burned to ashes return here to live again? The three authors of the Vedas were buffoons, knaves, and liars.
So, perception is the only means of valid knowledge. Inference is just a leap in the dark; going from the known into the unknown, though sometimes inference is apparently true. So, inference is rejected and verbal testimony too and even induction and deduction is argument in a circle.
This sect and the doctrine of materialism has been reject by all systems of Indian Philosophy and criticized in numerous writings. The view that rejects inference is itself a product of inference. Thoughts and ideas, not being material objects, cannot be perceived; they can only be inferred. So, the Charvaka is self-refuted and really no system of philosophy at all. Perception itself is often proved to be false and untrue.
If consciousness means self-consciousness it means they are humans and cannot be identified with the body. Animals also have bodies, but not rational consciousness. If consciousness is an essential part of the body it should be inseparable from the body, but it is not - it dies, faints or is otherwise in a dream state, etc. The knower cannot be reduced to only a body because since all objects presuppose the existent of the knowing subject.
The cause of consciousness cannot be a material object - if consciousness is a property of the body it should be able to be perceived like other material objects.
'A Critical Survey of Indian Philosophy'
by Chandrahar Sharma, M.A., D. Phil., D. Litt., LL.B.,
Shastri, Dept. of Phil., Benares Hindu U.