Does the universe in fact contain almost no information?

Abstract

At first sight, an accurate description of the state of the universe appears to require a mind-bogglingly large and perhaps even infinite amount of information, even if we restrict our attention to a small subsystem such as a rabbit. In this paper, it is suggested that most of this information is merely apparent, as seen from our subjective viewpoints, and that the algorithmic information content of the universe as a whole is close to zero. It is argued that if the Schrödinger equation is universally valid, then decoherence together with the standard chaotic behavior of certain non-linear systems will make the universe appear extremely complex to any self-aware subsets that happen to inhabit it now, even if it was in a quite simple state shortly after the big bang. For instance, gravitational instability would amplify the microscopic primordial density fluctuations that are required by the Heisenberg uncertainty principle into quite macroscopic inhomogeneities, forcing the current wavefunction of the universe to contain such Byzantine superpositions as our planet being in many macroscopically different places at once. Since decoherence bars us from experiencing more than one macroscopic reality, we would see seemingly complex constellations of stars etc., even if the initial wavefunction of the universe was perfectly homogeneous and isotropic.

How unitary cosmology generalizes thermodynamics and solves the inflationary entropy problem

“…The key assumption underlying the entropy problem is that quantum mechanics is unitary, so we will make this assumption throughout the present paper 1 . As described in [40], this suggests the history schematically illustrated in Figure 1: a wavefunction describing an early universe quantum state (illustrated by the fuzz at the far left) will evolve deterministically according to the Schrödinger equation into a quantum superposition of not one but many macroscopically different states, some of which correspond to large semiclassical post-inflationary universes like ours, and others which do not and completely lack observers. The argument of [40] basically went as follows:…”

Is “the Theory of Everything” Merely the Ultimate Ensemble Theory?

“…Rather, it is probably the apparent reduction in simplicity that appears disturbing, the quantity of information necessary to specify all these unseen worlds. However, as is discussed in more detail in [56], an entire ensemble is often much simpler than one of its members, which can be stated more formally using the notion of algorithmic information content [57,58], also referred to as algorithmic complexity. For instance, the algorithmic information in a number is roughly speaking defined as the length (in bits) of the shortest computer program which will produce that number as output, so the information content in a generic integer n is of order log 2 n. Nonetheless, the set of all integers 1, 2, 3, ... can be generated by quite a trivial computer program [59], so the algorithmic complexity of the whole set is smaller than that of a generic member.…”

“…In fact, this should suffice even if the computer lacks the CPU power and memory required to perform the decompression. The initial data might be simple as well [56], containing so little algorithmic information that a single CD-ROM would suffice to store it. After all, all that This would be a natural extension of a famous analogy by Eddington [28]:…”

Anthropic arguments outside of cosmology and string theory

“…That such a high degree of symmetry can indeed completely reproduce the situation in our particular cosmological domain becomes an immediate consequence (cf. Tegmark 1996;Collier 1996). Observation selection effect then accounts for features of the observed system required for the local observers to exist.…”