Secular Buddhists want to believe, like Stephen Batchelor, that rebirth was already prevalent in India during the time of the Buddha. Okay, we hear you. So, is it true that the notion of the cycle of rebirth was already firmly in place in India, let’s say, even before Gautama put forth his own teaching of rebirth? The answer has to be probably not. There is no compelling evidence to suggest that the idea of rebirth was widespread. (Emphasis is mine.)
(629) But this need not commit us to the view that rebirth (and karma) are uncritically or dogmatically accepted from the earlier or prevalent religious tradition. The only evidence adduced by those who put forward or suggest this view, is that rebirth is almost universally accepted in the Indian religious tradition. Since Buddhism too subscribes to this view, it is argued that Buddhism dogmatically accepted this theory from the prevalent tradition. From this it follows that the Buddha himself was violating the very injunction he was making, when he asked people not to accept a doctrine merely because it was found in a tradition, etc. (v. supra, 260).
(630) With all deference to scholarship, we wish to submit that this conclusion arises from both an unhistorical as well as an uncritical survey of the material. In fact, that a belief is found in a stratum A and in a chronologically successive stratum B, provides no conclusive evidence that the thinkers of stratum B uncritically and dogmatically accept it from the thinkers of stratum A. If we say so, it would follow that even a good scientist uncritically or dogmatically accepts the theories of his predecessors with whom he happens to agree, merely on the grounds of this agreement!
(631) Let us examine the credentials of the above widely accepted theory. In the first place it is false to say that rebirth was universally accepted by the Indian religious tradition prior to the advent of Buddhism. There is no trace of a belief in rebirth in the Rigveda, where we find only sporadic references to a belief in a life after death. The Atharvaveda, too, makes no reference to the doctrine. The Brâhmanas show a greater interest in the after-life and we meet with a variety of views on this subject but no conclusive reference to rebirth is found. The conception of a 'second death' (punar mrtyu) is pregnant with the possibility of developing the idea of rebirth and all that can be said is that 'the Brâhmanas contain all the suggestions necessary for the development of the doctrine of rebirth'” (K. N. Jayatilleke, Early Buddhist Theory of Knowledge (1963), pp. 371–72).
Is it true that Gautama knew of the arguments against the idea of rebirth which might explain, partially, why rebirth was not a widespread idea in India? More than likely. According to Jayatilleke the Buddha “would have been well acquainted with the Materialist critique of the doctrine of survival” (p. 375). Moreover, he would not have blindly accepted such a notion without having good grounds for it (cp. p. 375). After all, the Buddha was a religious maverick when it came to following religious traditions that there were no grounds for; who also went against the stream. He was the same Buddha who gave us the Kalama Sutta that said, among other things, that we shouldn’t go by traditions but by self knowing.