It is known that the concept of an observer plays important role in quantum mechanics. In interpretations with collapse only the observer can trigger the wavefunction collapse. From this naturally arises a question, whether the laws of nature were different before the observer appeared. It seems there can be at least two theories on this matter.
- First theory is that before the observer appeared the universe was in a mixed state and underwent unitary evolution following the universal wave function. With the first observation (when he experiences the first ever qualia) the universal wave function collapsed to a random (but probable) state consistent with the observer's existence.
Since before the first observation the universe was undergoing unitary evolution, it acted as a well-isolated from the external world quantum computer.
This means that the observer in principle may be able to spot relic interferences that distort the statistical behavior of the past, such as quantum jumps in biological evolutionary progress, similar to how quantum annealing allows jumps from one local minimum to another in an adiabatic quantum computer.
Unfortunately such differences can be spotted only by statistical methods, but this idea possibly completely compromised by the much greater influence of the anthropic principle on the observed statistics of the past. It is not evident whether the anthropic principle itself can be explained in terms of relic interferences.
Another major problem with detection of relic interferences is that with the increase of the complexity of a quantum system, the chances of interferences between different evolutionary paths and their eventual reconciliation quickly decreases. This fact has been proven by Thomas Breuer who showed that the increase of the complexity of a system (i.e. its entropy), its evolution under objective decoherence becomes virtually indistinguishable form its evolution under both objective and subjective decoherences (see below) with the contribution of the latter exponentially decreases (indeed it is quite more probable to see an interference of two states of an electron than two states of a Schroedinger's cat).
This suggests that relic interferences may be only observable at the very first moments after Big Bang when the entropy of the Universe was still very low.
- The second theory is that the laws of nature never changed, and wavefunction collapse happened always. This means that the observer effectively existed always and also always existed subjective decoherence. So the differentiation between these two theories lies in the existence of subjective decoherence before the birth of the observer.
A problem with this theory that postulating existence of the observer forever (even if unconscious) allows us to trace him (by the parental lineage of his cells for example) only up to 4 billion years back from now and then we only can refuge to the first theory.
That said I should note that Breuer published an article titled "Ignorance of the Own Past" that seemingly supports the second theory, but the result was obtained only with an assertion of determinism and the author notes that he does not know whether the result still holds in an indeterministic world.
So my question is whether this result was since improved to include indeterministic case so we could decide which of the two theories to prefer?