Great Filters: the Limits of Future Life

The concept of the Great Filter was introduced by Robin Hanson. According to it, the Fermi-paradox can be explained by the existence of a barrier that usually prevents the dead matter to become living and/or intelligent and albeit we were able to overcome it, the other candidates for either life or thinking wasn’t lucky/smart enough to get over it. In short: there are some factors that work against the living/intelligent beings.
Of course, it is only a theory and there are other, possible explanations for the “Great Silence” (=our missing “companion intelligences” in the Universe). For example: a low probability of life; or our inability to detect their signs; or we are the first intelligent races so it is not a surprise not to observe other intelligences in our light cone.
But we could adapt this Great Filter hypothesis for the future. Fred C. Adams (Long-term astrophysical processes, in: Global Catastrophic Risks, 2008) draws up our Universe’s very distant future up to 10^100 ears and regarding the survival of life, there are some fundamental turning points in the distant future of the Universe.
The first one is about the survuval of the earthly life. Our planet will be uninhabitable for an intelligent being within a 0.9 – 1.5 billion year and the biosphere will be “essentially sterilized in about 5.5 billion years” by the Sun. Notice that our environment in the Planetary System is not too life-friendly: a smaller start with 10% mass of the Sun would shine for trillion years (p. 44–46.). Regarding our actual knowledge about the pace of our human races’ technological developments, it seems to be possible to circumvent these problems–e.g. by migrating to another star.
The second barrier is more problematic. About 10^40 years later, because of the proton decay the matter in its traditional form will disappear and it means the “life as we know it”. (p. 47.)
It seems to be a serious “Great Filter” regarding the future of life and it would be a real challenge to find a solution which would be able to guarantee the survival of the life in this radically different physical environment. Of course, 10^40 year seem to be an unimaginably long time–but notice that it is not the end of the history of our Universe. The remains of the earlier era: the last black holes will be evaporated within a 10^100 years and only after it begins that epoch when “predictions of the physical universe begin to lose focus”. (p. 49.)
In other worlds: the living period (its end will be caused by the baryon decay) is like a phenomenon disappearing after the first trillionth – trillionth – trillionth… second of the Big Bang.  A 10^40 years are simply negligible to the remaining period of time.
So it isn’t evident to argue that the “aim” of our whole Universe is that momentary phenomenon of life. However, the final conclusion of the Strong Anthropic Principle is that the appearance of life is a necessity. But why not, for example, the black holes?
So we have two choices. We can either refuse the Strong Anthropic Principle as a ridiculous and flawed theory (and I tend to do it) or we can ask how it would be possible for the future life to survive these two Great Filters: the baryon and the black hole barriers–and it is a really exciting question.

The tree of cosmological natural selection

According to Lee Smolin, it is not a well-founded idea to apply Newton’s paradigm about the nature of physical laws without an approximation to the whole Universe, since it is based on a local observation and it suggests the existence of timeless laws which can be applied to a timeless space.
What is more, the Newtonian interpretation is unable to explain why the observed laws exist instead of others. Similarly, both our Universe’s high homogeneity and that this Universe is so far from thermal equilibrium are in question. Boltzmann answered the second problem arguing that it was a result of the fact that our world was born in an incredibly low-entropy state (it is the “past hypothesis”). But he simply replaced the original problem with a new one, since it is not known why was so low the entropy originally.
Generalizing this problem, the Newtonian paradigm is “a theory [which] has infinite of solutions,” but we observe only one Universe.
To solve this problem, one can introduce the multiverse hypothesis without changing the Newtonian paradigm. According to this logic, our Universe is a part of a bigger ensemble and we live in a biofil cosmic environment, because all of the possible universe-variations are realized, and we are simply lucky enough to find ourselves in a world of life-friendly conditions. But there is no testable predictions to falsify the multiverse proposal.
Smolin’s answer is the “cosmological natural selection”. It states that “the laws of nature have evolved over time” and he “decided to copy the formal structure of population biology by which populations of genes or phenotypes evolve on so called fitness landscapes.” The reproduction happens via black holes and the result is the birth of new baby-universes which inherit the physical laws of their parent universes’ laws in a slightly changed form (thanks to small, random changes). This process selects the more successful (=more back hole reproductive) universes and we presumably live in a successful universe which laws offers favorable conditions for black hole creation. And it is not a surprise, since life seems to be improbable without long-lived stars and carbon – which are necessary to the formation of black holes.
But this coincidence seems to be strange. Why the preconditions of black holes and life are the same?

• Perhaps it is only an observational bias and the physics of stars and the appearance of life are different phenomena without real connection, but there are other hidden, but cruical factors  – although we still didn’t realized them. Obviously, this explanation cannot be excluded, although it seems to be improbable.
• Perhaps the presence of long-lived stars, back holes and carbon are necessary preconditions of life, and these and only these preconditions lead to life.
• Or – and it seems to me the most probable – life can appear not only in carbon based universes, but our laws which leads to the creation of heavier elements allows its appearance. In other words: there are other, biofil universes without carbon, and it is another question whether there are another universes with different physics and different physical processes to reproduce themselves – perhaps even via more efficient solutions than the black holes. Namely: adapting Smolin's evolutionary approach, evolutionary processes are able to find only local maximums and the history of the descending baby-universes can be portrayed as an evolutionary tree. And it not sure that our branch is the most successful.