Also birth (jati) is one of the 12 links in the chain of dependent origination, which suggests to me (perhaps it's a radical idea here) that birth is dependent upon prior action. After all they are links; if birth is an entirely adventitious phenomenon, as it relates to kamma, at least, then why is it a link? Each link is both a cause and a result. So birth must be a both cause (of everything that comes after it) and a result of what comes before it, and prior links must be its cause. If not, what is its cause? The 12 links are a closed system in terms of cause and effect; otherwise, as with any experimental design, there is no force in the teaching (if there are extraneous causes---unaccounted for variables which produce the various links in the chain, the teaching is unpersuasive; other things might then account for each of the links and no thesis could possibly be proven). Can one be a Buddhist and take the position that birth is entirely unrelated to prior actions of body, speech, mind? I don't see how. Seeing the 12 links a representing a single lifespan breaks the chain at death.