You're assuming that a multiverse exists, and there's absolutely zero evidence to suggest that it does. If you can dismiss the evidence for God, you're hypocritical to believe in a multiverse, no offense intended.
But time travel isn't possible. It will never be possible. How do I know? Simple! We don't have a history that anyone has visited via time travel. If it had been done, we would have known about it.
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I understand the theory, but where is the evidence?
Multiverse theory has one chief purpose: to eliminate the need for a first cause to the universe. The problem is that is simply pushes back that question. What caused the multiverse? It still requires an unmoved mover.
There's simply no observable evidence for a multiverse, and no reason to think that one exists, unless you want to get a cosmology paper published in an astronomy journal.
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I love these back and forth exchanges. I'm glad to see you don't take offense, but I want to clarify.
On one hand, we have a claim that God exists. We have arguments for God and the necessity of a first cause for the universe, an argument from morality, an argument from the fine tuning of the universe, etc., yet many atheists want to see NATURALISTIC evidence of what is by definition BEYOND the NATURAL. They say there's no evidence for God.
On the other hand, we have a claim that a multiverse exists. We have theoretical arguments, but no necessary cause for a multiverse, no need for a multiverse to exist, and no observable evidence of its existence, yet many atheists accept that there is no NATURALISTIC evidence of a multiverse that is by definition part of the NATURAL world. They accept the existence of a multiverse.
See my consternation at this?
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The last word is yours ...