Is there objective Truth?

[Whateverist]

"Get with the times, huh?
Did I say Universe? Or did I say "all"? Can you envisage a scenario where those two are not coincident? I can.
Can we, humans, affirm that all that exists is contained in this Universe? NO."

The Universe IS all. Lol
Considering space time is expanding into NO space and NO time, it's safe to say there is no existence outside our universe. If you want to be a rebel and refuse to follow the evidence where it leads that's fine, but don't try and call me unreasonable.

The Universe is not necessarily all. Lol
We cannot tell if the Space-time within the Universe is unique, or if our Universe is in some subset of an infinite space-time.
And we know from mathematics that you can have an infinite subset within another infinite subset, so I see no contradiction.
Our Universe's space-time can very well be expanding within the infinite space-time.
There's no way to know that it's not the case, so you can't shut down that possibility and insert a super powerful conscious entity in there.

It is known that space-time itself can randomly produce matter. It is not inconceivable that, within the frame of an infinite space-time, in a few locations (possibly an infinite number of locations), such production was massive enough to provide a singularity that kick-starts a Universe, leaving its inhabitants blind to any outside process.
This is where the evidence leads.
Certainly, it's not proven and will likely never be... because of that singularity detail that prevents us from probing beyond it...
Check the work by the 2004 Physics Nobel Laureates.

" Ultimately, you can't claim anything about any beginning, because you don't know if there was one... you can only claim something about this Universe...."

Well we can have the upmost confidence this universe had a begining believing in an infinite regress of causality is more of a leap of faith than beleiving in an uncaused first cause. That everything just exists with no explanation is more of a stretch then magic

Well, the singularity has been arbitrarily posited as the starting point of this Universe, yes... the T=0. That says nothing about negative time in that scale.
Our calendars put t=0 at 2016 years ago.... allowing "negative time", so we should be careful.

So you think that space-time existing since all eternity and for all eternity is more of a stretch than the existence of a conscious, Universe-creating, eternal entity?
Occam's Razor, dude... which is simpler?

We observe simple things being put together to form complex things. Think of stars, the great material building furnaces of the Universe.

" Don't act like a smug human, thinking you know things you can't possibly know.
If you want to be honest, all you can say is that you don't know if there is a beginning. Anything else, you'll be having to preface everything with a mighty big IF."

Notice that i'm using words like probability, evidence, and the like. I do believe the universe had an ultimate begining, can i prove it empericaly? Nope. But considering the improbability of the contrary, and the evidence leaning heavily towards a begining, you're litteraly butting heads against all reason.

"It is said that an argument is what convinces reasonable men and a proof is what it takes to convince even an unreasonable man. With the proof now in place, cosmologists can no longer hide behind the possibility of a past-eternal universe. There is no escape: they have to face the problem of a cosmic beginning." -Velankin

There's Vilenkin again...
Enjoy:

Your lesson which appears ahead of the part I did quote needs to be readily available to all noobs. It would definitely have simplified things for me. But the part I did quote is so reasonably reasoned that I'm happy to quote it all even without picking it apart into smaller chunks.

Love the way you don't over sell any point or misrepresent any of it as being beyond question. Everything can always be questioned except for those who would posit an anything-goes zone called the supernatural and insist it is beyond all doubt based on a few considerations regarding logic. More to the point, they like to present a conundrum they can't make sense of (nothing-from-nothing, infinite regress, pick your favorite) as the undeniable basis for an unearned certainty in a supernatural solution. Hog wash.

Even more than that I like that I agree with the speculative part of what you have to say. I feel that you are absolutely correct regarding the possible broader context of "everything" for which we can probably never have empirical confirmation, trapped as we are within the fallout of a single singularity. I find people who agree with me to be among the brightest people I meet. So congratulations.