This looks familiar … ;o)
Well, a likely answer to the question about the space between universes, in analogy to, e.g. InterGalactic Medium (IGM) or IntraCluster Medium (ICM), would obviously be InterUniversal Medium, IUM.
To clarify the other point: There might be “predecessors” to our Universe, as there are new universes created in the IUM all the time, all over the place. I don’t think of an immediate predecessor specific to our Universe here. Essential problem: If the IUM is expanding, we are facing the question about this origin again, like with our Big Bang, “just” on a higher level. I don’t like to consider any infinity, but in this case it seems to apply.

The multiverse provides us with a satisfactory answer to this question: In the multitude of universes, all options are open, all variations can and will happen. We just happen to live in a universe where we note the conditions or, if you like, finely tuned elements.
To note that other universes might have intelligent life dealing with exactly the same questions, yet under totally different circumstances/ laws/ constants etc.

My position is that the theory is impossible to disprove; in fact, there are several good arguments which support the theory, string theory (yes, another theory which remains hard to prove) being one of them (cf. probable Calabi-Yau spaces).

Hi Martin,
Very well: First of all, I might remind you of an article from the ESA-HST page, dtd. 13 Oct 2016 (heic 1620), telling us that the HST revealed data of about roughly 10 times more galaxies in the observable universe than previously thought. As the HST is relatively weak the further it looks back, the results were only sketchy; the JWST will do much better than that, looking back not “just” some 13 billion lightyears, but about 1 billion lightyears further, up to the first formation of stars (and the said galaxies) and possibly peering into the realm of the “Dark Age”. Studying the formation process allows further insights into the “dark sector” of the universe, i.e. the workings of dark matter and the dark energy, the latter most likely being responsible for the expansion “drive” of the universe, hence giving us the Hubble factor (it is NOT a constant!). With this, we have (hopefully) the Hubble factor from the CMBR, then – new or with greater accuracy – the value of the first billion years.This would close a gap which right now is a wild area of equally wild speculation, even suggesting we might need “new physics” or should be fiddling around with various tuning methods of dark energy.
And, btw: I’m not so sure that we cannot achieve the large scale structures map! Of course, it won’t be with the JWST alone, but it gets us the beginning of the process, which is invaluable for the entire map, a large part of which we have already charted.

The (classical) Standard Model only covers a tiny part of the mass scale up to the Planck mass, so it would be extremely unlikely (and disappointing) not to find anything beyond. A different issue comes up as to HOW this region might be explored. The current technology is limited, and even some perspectives of improvement, as promising as it is, will not open up a large amount of that region. Of course, disproving the “Cyclic Model” would perhaps be worth it (and be fun) …

Of course, testable predictions used to be a fundamental requirement for any scientific theory – so far. But then, we are (were?) in a similar situation with string theory. A parallel in the past? Of course: Albert Einstein thought that there was no way to one day measure gravitational waves – and look where we are now! (Similar thing with black holes.) As for strings, there has been a hint of a discovery of a cosmic string, following a relatively simple theory about what to look for. All of this amounts to the obvious answer that of course, scientific methods should not be changed; the challenges are just higher than ever before.

Of course I’m still convinced of the theory of inflation, and so far I haven’t seen anything that would even raise a serious doubt. Admittedly there are a few questions regarding the very get-go of inflation; I’m not sure whether we ever get to answer this (and similar) questions. Maybe (just maybe) we’ll get more insights with improved instruments such as the JWST or even gravitational signatures which allow us to “poke” even further back in history, very much closer to the beginning of time itself.

Unfortunately it has not been made clear why special (or “right”) initial conditions would be required; most scientists think that this is NOT necessary and it would most likely be unphysical. What has been established, however, is that independent of initial conditions the release of the inflation would lead to the homogeneity and isotropy we observe today. Finally, we actually observe the “remnant” of inflation by the accelerated expansion of the universe – which is the same process running at a lower energy level (which is where the “dilemma” of a mismatch of 10^120 orders of magnitude between certain energy levels comes in). Given this “mismatch”, any low probability of a theory is not immediately ruled out, it’s just more or less (un-)likely; nothing more, nothing less – and it certainly doesn’t justify to misname a theory a “myth”.