MikeG wrote:...there would be no past to travel to in that verse.
Actually there would be, it would just look a hell of a lot different.
As you say moving between verse after verse is not time travel unless you actually go into the past and effectively rewind everything and all possible outcomes to whatever point you halt at. However, even if you then change something you shouldn't have this will have no bearing on any subsequent outcomes, because there will always be the alternate outcome where you did not do whatever and therefore changed nothing leaving all the unchanged strands playing out as they had done before.
Here's my take on time travel given what we know and my understanding of that. There is one verse, this one and whilst there may be other dimensions squirreled away, ours is the only one in which the structures and life like us can exist. In one scenario to travel back in time is to effectively rewind everything erasing / unmaking history as you pass it and therefore there is no going forward as nothing is there to travel to; to re-order the entire universe to an earlier stage does, however, seem to be a feat beyond any mechanism or capability to achieve. As that seems unlikely another option is that the entire thing exists like one big film and we're in the bit passing in front of the back-light and everything that happens is effectively predetermined. Assuming you could somehow travel in time, it would merely be an event already in the script and nothing could actually be changed; your only reward being the knowledge that everything you do is beyond your control, a marionette on a cosmic stage no one is watching. But what would stop you from going back and radically altering something or killing your earlier self and thereby creating a paradox? As travel could create such situations the answer would seem to be that either travel back is simply not possible or that the script ensures any such actions have been already accounted for, and any attempts to murder yourself or folks like Pol Pot all fail in some manner.
Or there is the notion of the multi-verse with all possible outcomes continually generating new verses - something that seems to entail the spontaneous creation of a universe of matter in an advanced state of order each time and thus looking a tad preposterous. Traveling back if even possible is a one way trip as one is left with an endless sea of possible futures wherever one stops and no way to choose any one over another. Making radical changes will only result in you now inhabiting one of those alternate possibilities and the futures that alternate allows for, in fact the very act of traveling back if such were possible would technically put you in a slightly altered verse anyway. This would seem to mean that it's also likely predetermined, that is, your travel was an already existing possible strand in the multitude of possibilities and this version of you is just following that script. Thus time travel would only occur in the strands that allowed for it and still necessitates a predetermined meta-verse.
Whether a single strand or a multi-verse, for there to be time travel would seem to entail a preordained system and can only exist if it's in the script. This would also appear to render time travel as effectively useless.
As I see it, time travel requires certain criteria to enable it and rests on these assumptions of what lies beyond our knowledge. I think we inhabit this verse, the present, the frame under the back-light is it, there is no rewinding as the task is impossible and the future is an endless sea of reasonable possibilities that, however, are no more than ephemeral probabilities of which only one is ever manifested while all the others which never truly existed vanish from contention. Time travel here is simply not possible.
Anyone still with me..., am I still with me...

Hope is but the first step upon the road to disappointment.