Ruminations on multiverses; they are not real (Introduction)

by David Turell , Friday, July 19, 2019, 22:12 (1953 days ago) @ David Turell

Another view that agrees:

https://www.forbes.com/sites/startswithabang/2019/07/16/you-must-not-trust-experiments-...

"Most scenarios involving parallel Universes like this are untestable, as we're restricted to living in our own Universe, disconnected from any others. Yet if one particular idea is right, there might be an experimental signature awaiting our investigations. But even if it yields positive results, you shouldn't trust it. Here's why.

"Whenever you have an experimental or observational result you cannot explain with your current theories, you have to take note of it. Robust measurements that defy the expectations of our predictions might turn out to be nothing — they might go away with more, improved data — or they might simply be errors. This has famously been the case many times,

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"However, sometimes there are results that really do appear to be puzzles: the experiments shouldn't turn out the way they did if the Universe works the way we think it does. These results often turn out to be omens that we're about to discover new physics, but they also frequently turn out to be red herrings that lead nowhere. Even worse, they can turn out to be duds, where they only appear to be interesting because someone, somewhere, made an error.

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"In all of these cases, as well as many others, it's important to get both the theoretical and the experimental work right. From a theoretical point of view, that means having a strong quantitative understanding about the expected signal that your new theory predicts as compared to the background signal that the prevailing theory predicts. You must understand what signals should be generated by both your new theory and the one it's seeking to supersede.

"From an experimental point of view, this translates into understanding your backgrounds/noise, and looking for an excess signal superimposed atop that background. Only by comparing your observed signal with the anticipated background and seeing a clear excess can you ever hope to have a robust detection. It was only when the evidence for the Higgs boson passed a certain significance that we could claim a definitive detection.

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"Any time you get a positive signal from an experiment, you cannot simply take that signal at face value. Signals can only be understood in relation to the noise background of the experiment, which is a combination of every other physical process that contributes to the result. Unless you quantify that background and understand the source of everything that your final signal is composed of, you cannot hope to conclude you've discovered a new phenomenon in nature.

"Science progresses one experiment at a time, and it's always the full suite of evidence that must be considered in evaluating our theories at any given time. But there is no greater false flag than an experiment pointing to a new signal extracted against a poorly understood background. In the endeavor of pushing our scientific frontiers, this is the one area that demands the highest level of skeptical scrutiny. Mirror matter and even a mirror Universe might be real, but if you want to make that extraordinary claim, you'd better make sure your evidence is equally extraordinary."

Comment: We live in this universe. How do we look out? The theory currently in vogue is if an other universe bumped into ours there should be a telltale circle in the CMB. There isn't. All the attempts are is to get rid of the appearance that the universe had a starting point and looks created.