I'm actually not aware of any Greek-speaking philosophers of antiquity who took the view that the cosmos had a beginning but not an end in time (though I'd welcome correction, if anyone does know of a counter-example!).
All the major players in this debate, in late antiquity, take creation and destruction to go together: either the cosmos had/will have both a beginning an end in time, or it had/will have neither of these.
On the latter (Platonic) view, the "coupling" of these follows from the way in which we're thinking about the divine causes of the universe: (a) as Final Cause, the transcendent Good at which everything is always aiming, (b) as Paradigmatic Cause, and (c) as Efficient or Demiurgic cause, who (as Plato describes in the Timaeus) looks to that eternal paradigm and brings it into manifestation in order to realize that Good. What's important is that all three of these causes are eternal in the strongest sense: they are outside of time, and they are themselves utterly unchanging: recall here the discussion we had a few months back about how the Gods cannot possibly change, either for the better or for the worse.
So, because these transcendent causes are independent of time, and are themselves utterly unchanging, there's no good reason why they would bring about their effect (the existence of the cosmos) at one time but not another.
That's the general line. Of course, if that basic account is not compelling, then we might need to start playing whack-a-mole, as various "good reasons" for that temporal variation are considered and refuted. But I take it that this strong account of eternity and divine unchangeability are at the root of the Platonic position.
no subject
I'm actually not aware of any Greek-speaking philosophers of antiquity who took the view that the cosmos had a beginning but not an end in time (though I'd welcome correction, if anyone does know of a counter-example!).
All the major players in this debate, in late antiquity, take creation and destruction to go together: either the cosmos had/will have both a beginning an end in time, or it had/will have neither of these.
On the latter (Platonic) view, the "coupling" of these follows from the way in which we're thinking about the divine causes of the universe: (a) as Final Cause, the transcendent Good at which everything is always aiming, (b) as Paradigmatic Cause, and (c) as Efficient or Demiurgic cause, who (as Plato describes in the Timaeus) looks to that eternal paradigm and brings it into manifestation in order to realize that Good. What's important is that all three of these causes are eternal in the strongest sense: they are outside of time, and they are themselves utterly unchanging: recall here the discussion we had a few months back about how the Gods cannot possibly change, either for the better or for the worse.
So, because these transcendent causes are independent of time, and are themselves utterly unchanging, there's no good reason why they would bring about their effect (the existence of the cosmos) at one time but not another.
That's the general line. Of course, if that basic account is not compelling, then we might need to start playing whack-a-mole, as various "good reasons" for that temporal variation are considered and refuted. But I take it that this strong account of eternity and divine unchangeability are at the root of the Platonic position.