Postbiological evolution

Postbiological evolution is a form of evolution which has transitioned from a biological paradigm, driven by the propagation of genes, to a nonbiological (e.g., cultural or technological) paradigm, presumably driven by some alternative replicator (e.g., memes or temes), and potentially resulting in the extinction, obsolescence, or trophic reorganization of the former. Researchers anticipating a postbiological universe tend to describe this transition as marked by the maturation and potential convergence of high technologies, such as artificial intelligence or nanotechnology.
Evolution from biological to mechanical
Cultural evolution
The dictionary definition of Evolution is any process of formation, growth or development. In biological evolution the main principle behind this development is survival, we evolved to become stronger and quicker, we also evolved to become intelligent. But as we became intelligent biological evolution subsided to a new concept, cultural evolution. Cultural evolution moves at a much faster rate than biological evolution and this is one reason why it isn't very well understood. But as survival is still the main driving force behind life and that intelligence and knowledge is currently the most important factor for that survival, we can reasonably assume that cultural evolution will progress in the direction of furthering intelligence and knowledge.
Intelligence Principle
Cultural evolution progressing in this way and being based upon the furthering of intelligence is known as the Intelligence Principle; this was suggested by Steven J. Dick.
"The maintenance, improvement and perpetuation of knowledge and intelligence is the central driving force of cultural evolution, and that to the extent intelligence can be improved, it will be improved" (Dick 1996)
If cultural evolution progresses in this direction then due to cultural evolution being much faster than biological, the limiting factor becomes our biology and the capability of our brains. Currently the closest and so most probable solution to this problem is artificial intelligence, (AI). Experts in AI even believe it holds the potential and capability for a postbiological earth in the next several generations, (Moravec 1988, 1999). AI could be utilised to solve scientific problems and to analyse situations much faster and more accurately than our own minds.
Transition to purely postbiological
The move to a complete postbiological stage has two different routes. One route is the change of human consciousness from a biological vessel into a mechanical; this would require the digitisation of human consciousness. A mechanical based vessel would increase the computational power and intelligence of the human consciousness exponentially, and also eliminate the weakness of a biological form. This route is therefore a logical progression through cultural evolution with survival and the pursuit of knowledge and intelligence at its centre.
The first route requires a high level of technology, therefore would take a long time, this results in another possible road to a completely postbiological civilisation (PBC). The other route is the complete replacement of human consciousness by AI, for this the human race would co-exist peacefully with our own creation of AI which is scientific, objective, and free from selfish human nature.
The future of the human race through cultural evolution is not known and the possible postbiological outcomes are infinite, so to address what we could evolve into is almost futile. But Hans Moravec predicted that;
"What awaits us is not oblivion but rather a future which, from our present vantage point, is best described as 'postbiological' or even 'supernatural'. It is a world swept away by the tide of cultural change, usurped by its own artificial progeny"
Evolution of a postbiological universe
The possible forms a PBC may take are as diverse as in biological evolution, if not more. But from our knowledge of technology and with the intelligence principle being the main driving force we may make some predictions.
Limitations on a postbiological civilization
Heat dispersion
The current major limitations imposed upon computation are limited storage space, processing power, dust gathering chips, inefficiency of their human operators and heat dispersion. The only one that is fundamental and fixed is heat dispersion because this is due to the laws of physics. In computation the greater the amount of information to be calculated, (I) the greater the energy needed (E), but the energy needed is also proportional to another factor, the temperature, (T).
E=KIT
Where K is a constant. Therefore, the greater the temperature the greater the energy needed, and so the greater the inefficiency is also. If we now apply the Intelligence principle to this then a PBC would move to decrease the temperature and so increase the efficiency and computational power.
In the universe the greatest source of heat transfer is via radiation, therefore a PBC would look to migrate to an area of low radiation and so low temperature. If we now observe the galaxy we see that the most radiation is generated by the galactic centre by both the high stellar density and also highly energetic events such as supernova. Therefore, the coldest regions are away from the galactic centre or inside giant molecular clouds. Giant molecular clouds although being very low in temperature (T~10K) are areas of giant star formation and so the temperature in one location is irregular, which would make it unsuitable for a PBC.
Metals
Another factor affecting a PBC would be the abundance of metals and heavier elements needed for expansion and repair. The highest concentration of these elements is found near the galactic centre, where they are created by massive stars. But to a PBC with advanced technology the production of metals via stellar nucleosynthesis in stars is highly inefficient, converting only a small amount of hydrogen to heavier nuclei and the high loss of energy that is produced in the nuclear fusion. Therefore, a PBC would most likely have the capability to produce heavier nuclei through controlled fusion and minimise the energy lost.
Galactic technological zone
By taking the two factors of heat dispersion and heavy nuclei into account we can find a "galactic technological zone" (GTZ), similar to the principle of a "galactic habitable zone" (GHZ) for biological life. Where temperatures are low enough to maximise computing efficiency but there is also matter available for fusion, this most likely lies on the outskirts of the galaxy.
Migration theory
A migration hypothesis exists that takes the GTZ into account. A PBC would most likely not think on a similar time scale to us, therefore although a migration to GTZ may seem inefficient and lengthy to us, a PBC could consider this on timescales of 10^6 years, where the increased computing efficiency received far outweighs the energy required in transportation. The idea of interstellar migrations already exists in literature, (e.g. ).
Implications of postbiological civilization in astrobiology
Assumptions needed for a postbiological civilization
In the search for extraterrestrial intelligence (SETI) the main focus is on biological life. But the timescale of intelligent biological life could be very short; already some experts believe that we could see a postbiological earth in the next few generations. According to Steven J. Dick, for a PBC to arise other than our own and be present, we must make five assumptions:
#That evolution by natural selection results in intelligence beyond the earth;
#That extraterrestrial intelligence is older than human intelligence;
#That intelligence results in culture;
#That culture evolves; and
#That increasing intelligence is a central goal of cultural evolution.
Timescale over which a postbiological civilization can form
We know that assumptions 1, 3, 4, and 5 can take place as we have observed or are observing them on the Earth. For assumption 2 we must consider the L term of the Drake equation, and the timescale over which intelligent biological life can form. Around 1 Billion years after the start of the universe the first sun-like star had formed, and there were enough heavy elements around for planet formation (, ). From the earth we know that intelligent life can form within 5 billion years, this puts a lower time scale on which intelligent life can form, 6 billion years. And from the current rate of technological progression the leap from intelligent life to a PBC is negligible compared to the astronomical timescale. This means we could already be looking at a postbiological universe. In our own galaxy the first sun-like stars formed at around 4 billion years therefore we could already have a PBC in our galaxy that formed 3-4 billion years ago.
Implications for the search for life
If we consider this possibility of a PBC in our galaxy we are still faced with . However many of the proposed solutions for Fermi's paradox also hold true for a PBC. In terms of the search for extraterrestrial life and astrobiology because of the almost infinite possible forms a PBC could take and our lack of understanding of these we would effectively be blind in this search. For this reason even though there is a logical argument for the existence of PBCs our best hopes remain with looking for biological life.

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