Thanks for responding. It’s rather gratifying to have an articulate and philosophically trained adversary in this sort of debate.
Let me start with your last point, about the constitution of matter. The evidence from the Early Buddhist Texts (EBTs) suggests the Buddha never set out to understand the nature of the material world. His insights into cosmology, assuming they are such, were really a by-product of his spiritual search for an end to suffering. A full understanding of suffering requires a comprehensive understanding of existence. It was only as part of this search that he came to see aspects of cosmology. Or this, at least, appears to be the view from the EBTs.
As for the fundamental elements of matter, there was probably no reason for the Buddha to take an interest in this. The analysis of matter into “the four great elements” was probably sufficient for his purpose, which was simply to show that the material body is no different from external materiality. Even if he had known about the elements of the periodic table – and I cannot see any reason why he would – it would have been counterproductive to bamboozle his audience with unnecessary information, even if this happened to reflect more accurately the makeup of the physical world. It was easier and more productive for the Buddha to pass on his message using an existing framework for understanding matter – which after all was close enough to reality in its own limited way – than to try to discover a deeper reality and then teach that, assuming he even had this ability. According to the simile of the handful of leaves, the Buddha left most of his knowledge out of his teachings, simply because it was irrelevant to the task at hand, the ending of suffering.
Your reference to Greek philosophy is interesting, and it seems clear that the Stoic conception of the universe has much in common with the Buddhist conception. I can see three potential explanations for this: (1) Coincidence, perhaps due to a propensity for humans to think along similar lines; (2) a common source for the correct understanding of the universe; (3) borrowing from one civilisation to the other. Personally I think the third option is quite likely to be true. In his work “The Shape of Ancient Thought,” the scholar Thomas McEvilley has shown how much information seems to have flowed between ancient India and ancient Greece. He mentions, for instance, reincarnation, which he argues was a Pythagorean borrowing from India.
The second possibility – that both cultures tapped into a common source of knowledge, perhaps the recollection of past lives 
– cannot be eliminated. I am not sure how to evaluate this, however, and so I will leave it out.
The first possibility seems unlikely to me, unless it can be shown that this idea has arisen independently in a number of different cultures. It has been shown, for example, (by the Princeton University anthropologist Gananath Obeyesekere, in “Imagining Karma: Ethical Transformation in Amerindian, Buddhist, and Greek Rebirth”) that the idea of reincarnation has arisen independently in a number of different cultures. But I am not aware of any studies that show the same for cosmological models. In sum, I think the third option is most likely to be true.
But I don’t want to push this argument too far. There is enough uncertainty about the exact meaning of the Pali to avoid making too strong a claim. What we find in the suttas is a description of the world (loka) going through a period of evolution (vivaṭṭati, “rolling out”) followed by a period of devolution/dissolution (saṃvaṭṭati, “rolling together”), each one called an “aeon,” a kappa. One aeon is followed by another, etc., and so we are seeing a cyclical pattern. From the context it is clear that these aeons were very long (they occur at the end of a sequence of ascending numbers of rebirth, following the number 100,000). Given this meagre information, it is impossible, I think, to know with certainty what these texts mean by “world-evolution.” Still, taking into account the broader outlook of the EBTs (including what appears to be the gradual reappearance of the world after the end of an aeon, the rebirth of beings in non-physical realms when the aeon comes to an end, etc.) I do think, on balance, that the suttas are describing a Big Bounce model of the universe.
What is more remarkable than the apparent Big Bounce model, however, is the description of the warming up of the sun and the burning up of the Earth in the Severn Suns Sutta at AN 7.66. Here there is much less scope for interpretation, I think, and I would guess the passage is unique to Buddhist cosmology. And what about the suttas that mention life in other solar systems? Is there any parallel to this in any other ancient culture?
Thanks. My understanding is that Purānas post-date the Early Buddhist Texts by many centuries. So I do not think this is enough to show that Brahmanism had similar ideas that were independent of Buddhism. Nevertheless, this is certainly interesting, and it shows the close connection between the various religions of India.
Well, yes, large numbers should not taken as being precise references. Still, the suttas distinguish between one hundred, one thousand, a hundred thousand, etc. For these distinctions to be meaningful they cannot just refer to any large number, but must be relatively close to the number mentioned. So when we read one thousand to the third power, we can assume, I think, that it means something in the ballpark of one billion.
And thanks to everyone else for your additional information and kind comments. More later.
