Paul wrote:...Nagasena was a theravadin monk...
Really? How do you know this? If you mean Theravadrin in contrast to Sarvastivadin (or some other early Buddhist school) I don't know if this can be established. If you mean Theravadrin as opposed to Mahayana, then I think you may find that the theoretical (the artifice of) "splitting" of Buddhism into two Yana (Vajrayana was nowhere near conception yet, Garab Dorje was born around 55AD and Padmasambhava did not bring the teachings to Tibet until around 760AD) took place after the existence of Nagasena (apparently the earliest mention of the Yana was around 100BC-100AD, some 50 -150 years after Nagasenas death) so at that point there was officially no Yana split. And anyway, the actions and teachings of character/individual Nagasena may basically have been "borrowed" by the Theravadrin school to support/advertise their teachings. So what is the basis for this statement?
... and they don't believe in a state between lives - it's straight into the next existence, although there is evidence in the pali canon of Buddha talking about such a thing.
According to Theravadra Abhidhamma there is a moment of consciousness between the two lives called rebirth linking consciousness, since it belongs neither to the previous nor to the following life it is safe to assume that it is a bardo, or "intermediate", state of consciousness. It does not last as long as the Bardo state of the Bardo Thodol but, really, the of passing/measurement of time is so relative when consciousness splits from physical form that...
As an aside, if you meant Theravadrin as opposed to the other Yana it seems that the concept of an intermediate state existed in many of the "Hinayana" schools:
From the records of early Buddhist schools, it appears that at least six different groups accepted the notion of an intermediate existence (antarābhava), namely, the Sarvāstivāda, Darṣṭāntika, Vātsīputrīyas, Saṃmitīya, Pūrvaśaila and late Mahīśāsaka. The first four of these are closely related schools. Opposing them were the Mahāsaṃghika, Mahīśāsaka, Theravāda, Vibhajyavāda and the Śāriputra Abhidharma (possibly Dharmagupta) (Bareau 1955: 291).
AdmiralJim wrote:I think it is possible for rebirth to be possible because of the simple fact that when you die the atoms have nowhere to go
Hmmmm... Now all you have to do is establish that consciousness resides in atoms because (apparently) it is the mind stream that is reborn in a new physical form and not the physical form (which is composed of atoms) that is being reborn.