Zoink!

Why would the above reasoning not push, or at least float, the cosmological constant even lower than the observed value? The authors’ reasoning is that additional galaxies reachable in later time are mostly “used up”, so don’t provide much additional weighting. However, it’s been suggested that burnt-out stars retain most of their energy value to an advanced civilization (e.g. feeding helium etc into black holes for energy).

Suppose intelligent life is rare, but not that rare, and over distances substantially larger than our horizon, expanding bubbles of civilization are likely to bump into each other, thereby negating further weight bias.

By that interpretation – with additional disclaimer, obviously this is even more extremely tentative than my earlier comment – the above papers just might constitute the very first evidence for a lower bound on the frequency of intelligent life.

Prior distribution of cosmological constant is linear random. So observed value of 1e-123 is exponentially unlikely, expected value is near 1.
But values higher than 1e-120 disrupt galaxy formation, hence unobservable.
This leaves 3 orders of magnitude unaccounted for, because intelligent life could almost as easily appear with 1e-120 as 1e-123. The galaxies would rapidly vanish from each other’s sight, but each would still evolve life.

Specifically, suppose possible values are weighted by number of observers per baryon (as previous authors have done). That weighting doesn’t care to reduce cosmological constant much past 1e-120, on the assumption that intelligent life evolves in every galaxy, so it doesn’t matter if the galaxies separate rapidly.

The above authors reproduce the observed value 1e-123 by weighting by number of observers per causal diamond (roughly speaking, per Hubble volume). In other words, their weighting cares to reduce it to 1e-123 on the assumption that it’s important that the galaxies stay in contact with each other at least until a decent fraction of their energy reserves have been used up.

This makes sense (my interpretation, the authors talked only in terms of entropy production by dust heated by starlight) if we assume most galaxies don’t evolve intelligent life. Therefore the actual number of observers per whatever divisor you choose, will be determined by the number of galaxies to which observers, once evolved, can spread. A typical observer will, therefore, find himself in a universe where the cosmological constant was small enough for intelligent life evolving in one galaxy to spread to many others before they disappeared from sight.

Therefore (with obvious disclaimer about extreme tentativeness of such conclusions) the above findings arguably constitute evidence that intelligent life is rare.

‘As far as you can tell’ doesn’t go far enough. You’re confusing the system that implements the observers with what they’re observing – their experiences are necessarily low-entropy. The Anthropic Principle dicates the sorts of worlds that the observers will perceive themselves to be in.

Your inability to perceive order in the chaos is akin to complaining that most of the Library is nonsense static and ignoring the fact that it contains the Grand Unified Theory.