Cosmology; importance of a beginning (Introduction)

by David Turell , Tuesday, May 07, 2019, 00:25 (2028 days ago) @ David Turell

Cosmology has problems related to theories of a beginning:

https://principia-scientific.org/cosmology-has-some-big-problems/

Born out of a cosmic explosion 13.8 billion years ago, the universe rapidly inflated and then cooled, it is still expanding at an increasing rate and mostly made up of unknown dark matter and dark energy … right?

This well-known story is usually taken as a self-evident scientific fact, despite the relative lack of empirical evidence—and despite a steady crop of discrepancies arising with observations of the distant universe.

In recent months, new measurements of the Hubble constant, the rate of universal expansion, suggested major differences between two independent methods of calculation. Discrepancies on the expansion rate have huge implications not simply for calculation but for the validity of cosmology’s current standard model at the extreme scales of the cosmos.

Another recent probe found galaxies inconsistent with the theory of dark matter, which posits this hypothetical substance to be everywhere. But according to the latest measurements, it is not, suggesting the theory needs to be reexamined.

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For a crucial function of theories such as dark matter, dark energy and inflation, which each in its own way is tied to the big bang paradigm, is not to describe known empirical phenomena but rather to maintain the mathematical coherence of the framework itself while accounting for discrepant observations. Fundamentally, they are names for something that must exist insofar as the framework is assumed to be universally valid.

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Consider the context of the problem and its history. As a mathematically driven science, cosmological physics is usually thought to be extremely precise. But the cosmos is unlike any scientific subject matter on earth. A theory of the entire universe, based on our own tiny neighborhood as the only known sample of it, requires a lot of simplifying assumptions. When these assumptions are multiplied and stretched across vast distances, the potential for error increases, and this is further compounded by our very limited means of testing.

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The crux of today’s cosmological paradigm is that in order to maintain a mathematically unified theory valid for the entire universe, we must accept that 95 percent of our cosmos is furnished by completely unknown elements and forces for which we have no empirical evidence whatsoever. For a scientist to be confident of this picture requires an exceptional faith in the power of mathematical unification.

In the end, the conundrum for cosmology is its reliance on the framework as a necessary presupposition for conducting research. For lack of a clear alternative, as astrophysicist Disney also notes, it is in a sense stuck with the paradigm. It seems more pragmatic to add new theoretical floors than to rethink the fundamentals.

Contrary to the scientific ideal of getting progressively closer to the truth, it looks rather like cosmology, to borrow a term from technology studies, has become path-dependent: overdetermined by the implications of its past inventions.

Comment: Not a very solid edifice. Please read on in the next entry for a different set of thoughts.