I'm reading Peter Robb's A History of India, and on page 35 he says
A summary in Digha Nikaya [of the Arthava Veda] offers the following... a belief in fate not works, an atheistic materialism, a theory of physical elements (easily preceding Greek speculations on atoms), and a virtually 'post-modern' scepticism...
So what was the Arthava Veda's theory of physical elements? When was it written? It's not hard to imagine it being earlier than Lucretius, but also the pre-Socratics?
Secondary questions: I'm also interested in the atheistic materialism. I might want to read the Arthava Veda itself, or a book on it. Any suggestions on translations or books about it? Also, does anyone have a familiarity with this book I'm reading? Any criticism of it? It's a little short on dates and specifics, at least in the early stages, but that's not the worst.
I'm not versed with text of the Atharva Veda, so I won't argue any merits or lack thereof of the text.
The four original Vedas can however be easily placed to be before the pre-Socratics. The late Vedic period is considered ended in 500 BC. The four original Vedas are comfortably out of this region. The Atharva Veda is said to have been completed by 900 BC (Introduction to Hinduism by Gavin Flood).
There's a chance you might find better luck on the theory and text of Atharva Veda in /r/hinduism.