Just to think that someone propounded such a profound and rational school of thought, almost two and a half millenia ago, sends shivers up your spine. The original charbakasutra is lost, so the only way to reconstruct it is to collect fragments of it surviving in other sources, commentaries and books like Madhavacharya's sarvadarsanasamgraha. A great job has been done in recent times by Dr Ramkrishna Bhattacharya from Ananda Mohan College, Kolkata. I'll advice you to go through his paper (Journal of Indian Philosophy 30: 597-640, 2002). I'll be quoting all the aphorisms attributed to Charvaka from the above text, and leave it to the reader to read the commentaries etc for him/herself.
Lokayata, as his school of thought came to be subsequently known, is outside the six schools of indian religious philosophy (which includes samkya, the other atheistic(?) school), and is a nastik school along with buddhism and jainism. But as you can see from the aphorisms below, it's truly materialistic and in keeping with our present scientific understanding of the world. If nothing else, it offers a sense of continuity for indian atheists like us, there were others like us before, who lived in these lands, who had the courage as well as humbleness to see the world for what it was, cutting through the fog created by religion.
The aphorisms:
1. bhutavada
(materialism)
1.1 athatastattvam vyakhyasyamah
(we shall now explain the principles)
1.2 prthivyapastejovayuriti tattvani
(earth, water, fire and air are the principles, nothing else)
1.3 tatsamudaye sarirendriyavisayasamjnah
(their combination is called the "body", "sense" and "object")
1.4 tebhyaschaitanyam
(consciousness arises/is manifested out of these)
1.5 kinvadibhyo madasaktivat
(as the power of intoxication arises/is manifested from the constituent parts of wine)
1.6 chaitanyavisitha kayah purusah
(the "self" is nothing but the body endowed with consciousness)
1.7 sarirad eva
(from the body itself)
1.8 sarire bhavat
(because of it's [consciousness] existence where there is a body)
1.9 jalabudbudavajjivah
(souls are like water bubbles)
2. svabhavavada
(the doctrine of inherent nature)
2.1 janmavaichitryabhedajjagadapi
(the world is varied due to the variation of origin)
2.2 mayurachandrakavat
(as the eye in the peacock's tail)
3. pratyaksapradhanyavada
(the doctrine of the primacy of perception)
3.1 pratyaksham (ekam) eva pramanam
(perception indeed is the only means of right knowledge)
3.2 pramanasyagaunatvad anumanad arthanischayo durlabhah
(since the means of right knowledge is to be non-secondary, it is difficult to ascertain an object by means of inference)
4. punarjanmaparalokavilopavada
(the doctrine of the denial of rebirth and the other world)
4.1 paralokasiddhau pramanabhavaat
(there is no means of knowledge for determining the existence of the other-world)
4.2 paralokino'bhavat paralokabhavah
(there is no other-world because of the absence of any other-worldly being [ie. the transmigrating self])
4.3 paralokichaitanyam niravayavatvaat
(due to the insubstantiality of consciousness residing in the other world)
5. vedapramanyanisedhavada
(the doctrine of the uselessness of performing religious acts)
5.1 dharmo na karyah
(religious act is not to be performed)
5.2 tad upadesesu na pratyetavyam
(religion's instructions are not to be relied upon)
I can't help myself from quoting a wonderful verse attributed to Charvaka:
na svargo napavargo va naivama paralaukikah /
naiva varnasramadinam kriyascha phaladayikah //
(there is no heaven, no final liberation, nor any soul in another world
nor do the actions of the four castes, orders, etc., produce any real effect)
