Is "the theory of everything'' merely the ultimate ensemble theory?

TL;DR

This paper explores the 'ultimate ensemble theory' where all mathematically possible worlds exist, examining its physical implications, testability, and whether it can be empirically distinguished from other theories.

Contribution

It introduces and analyzes the 'ultimate ensemble theory', proposing it as a parameter-free, mathematically grounded framework with testable predictions about physical reality.

Findings

The theory's predictions are probability distributions for experimental outcomes.

It may be empirically distinguishable by comparing predicted and observed physical constants.

The theory remains consistent with current observations and is not yet ruled out.

Abstract

We discuss some physical consequences of what might be called ``the ultimate ensemble theory'', where not only worlds corresponding to say different sets of initial data or different physical constants are considered equally real, but also worlds ruled by altogether different equations. The only postulate in this theory is that all structures that exist mathematically exist also physically, by which we mean that in those complex enough to contain self-aware substructures (SASs), these SASs will subjectively perceive themselves as existing in a physically ``real'' world. We find that it is far from clear that this simple theory, which has no free parameters whatsoever, is observationally ruled out. The predictions of the theory take the form of probability distributions for the outcome of experiments, which makes it testable. In addition, it may be possible to rule it out by comparing its a priori predictions for the observable attributes of nature (the particle masses, the dimensionality of spacetime, etc) with what is observed.