2022-05-04 Email to Noam Chomsky
Dear Noam,
I have been doing a thought experiment to determine the implications of an infinite universe on the rarity of civilised life in the universe, to present to an upcoming conference on astrobiology.
My thesis is that there have been a number of astonishing flukes to get us where we are as a civilisation. But, thinking about your theory of language and hearing a discussion on BBC radio 4 about Homo erectus, I decided that the most recent fluke occurred for the spontaneous creation of a language mechanism in the brain, capable of being passed on down the generations, presumably through genes. I have written to Mark Maslin to check the timing of this fluke, which would explain how, when Homo sapiens left Africa, it was able to out-compete all the other species, including the extremely successful Homo erectus.
I regard this as an astonishing confirmation of your theory of language, so I had to tell you ASAP!
Best wishes, John
Full thesis:
You may be aware of the Rare Earth hypothesis, publicised in a book by Ward and Brownlee in 2000 [1]. They argue that the universe is generally hostile to complex life; and whereas life may be common, complex life “requires an exceptionally unlikely set of circumstances”. I am arguing that an Earth with life is extremely rare; an Earth with intelligent life is as rare again; and an Earth with a civilisation is as rare again. It requires extreme fluke upon extreme fluke upon extreme fluke. But, however unlikely the emergence of a civilisation might be, this emergence will necessarily occur in an infinite universe. Moreover there will be an infinite number of instances.
We have an observer bias to think that our situation is normal, and there must be other planets out there in the galaxy with life. But I argue that life is astonishingly abnormal in the infinite universe, with intelligent life much rarer by a colossal factor, and civilisations much rarer still by a further colossal factor.
There has to have been a chain of flukish events or conditions for our civilisation to have emerged:
- The universe has to have the universal constants with extremely precise values to allow: expansion of universe (at least locally within the visible extent of the universe); formation of galaxies with stars and planets; explosion of stars into super-novae to create a variety of elements in considerable quantities; H2O such that the solid form floats on the liquid form; Fe for forming an Earth core with magnetism and tectonic movement; C for a DNA helix to allow evolution; and Cl for chlorophyll to allow photosynthesis.
- There has to be a means to collect and concentrate these elements for planet building such that the planet has enough H20 for oceans, Fe for an iron core, C for a carbon cycle, etc.
- The simplest life requires the exceptionally unlikely event of the assembly on the planet of precisely the necessary atoms and molecules as ingredients for a life structure: utilising an energy source and with the capacity for replication and evolution.
- Then we need the even rarer event or “quantum leap” of this life structure’s spontaneous creation, only conceivable through quantum uncertainty.
- Further exceptional physical conditions are required for life’s continuance from the first second of existence for billions of years.
- Further rare physical conditions are required for further quantum leaps, as almost certainly required for the spontaneous emergence of multi-cellular life with various degrees of sentience and intelligence through quantum uncertainty.
- Further exceptional conditions are required for the continuance of this intelligent life for hundreds of millions of years, and luck in survival from near extinction.
- For the past 2.5 million years we must note the existence of Milankovitch cycles which have driven the coming and going of ice in the Northern Hemisphere. The existence of such freakish cycles, leads to the conclusion that there must be an even more exceptional event to follow: a quantum leap.
- This relatively recent event could be the spontaneous emergence of a language capability in the human brain, promoted through genes to the entire Homo sapiens population as required for a civilisation as we know it. This could be the final quantum leap for our civilisation to emerge. It happened in Africa prior to the Homo sapiens “out of Africa” event, 60-50 kya, when our species ousted all the other species of hominid.
All these low probabilities are multiplied together, fluke upon fluke, in order to obtain a civilisation of intelligent beings capable of observing that they exist, as we are doing today.
The Drake equation [2] is the multiplication of small probabilities. In the “Extremely rare Earth” hypothesis we also have a number of these probabilities, but each of them is mathematically extremely small: e.g. less than one in 10^10^10^10. To give you some impression of this unlikelihood, assume the chance of a tossed coin landing on its edge is one in 10^10 (i.e. 10 billion). Then hitting the jackpot to obtain a civilisation within a given volume of universe (such as the visible universe) requires the tossed coin to land on its edge over ten billion times in a row. The chance of other life within the visible universe is very nearly zero.
Within the flukes there are two categories. First are the physical flukes – events or conditions leading up to quantum leaps; they obey Newtonian physics. Second are the far less likely quantum leaps, which are dependent on quantum uncertainty of position to allow the spontaneous emergence of a significant biological structure out of a random mixture of atoms and molecules.
Can we extrapolate into the future? The Milankovitch cycles have provided us with several thousand years of anomalously stable temperature, climate and sea level, to allow for the development of our modern civilisation, which has become very dependent on this stability. We have upset this stability by mimicking a Milankovitch warming signal; this signal has been amplified in the Arctic through albedo loss. We can already observe a dangerous disruption of the jet stream producing extremes of weather and climate. And we can observe acceleration in the rate of sea level rise, with ice mass loss from the Greenland Ice Sheet and from glaciers elsewhere in the Arctic. We have to take the situation into our own hands, since we can no longer rely on luck to save ourselves. We must intervene, most urgently to cool the Arctic.
Best wishes,
John Nissen,
Bath, UK
Mobile: +44 7890 657 498
[1] https://en.wikipedia.org/wiki/Rare_Earth_(book)
Ward and Brownlee argue that the universe is fundamentally hostile to complex life and that while microbial life may be common in the universe, complex intelligent life (like the evolution of biological complexity from simple life on Earth) required an exceptionally unlikely set of circumstances, and therefore complex life is likely to be extremely rare. They argue that among the essential criteria for life are a terrestrial planet with plate tectonics and oxygen, a large moon, magnetic field, a gas giant like Jupiter for protection and an orbit in the habitable zone of the right kind of star. Additionally, events during the Earth’s geological past such as Snowball Earth, the Cambrian Explosion, and the various mass extinction events that nearly destroyed life on Earth arguably make the existence and survival of complex life rare as well. They also suggest that animal life, having taken hundreds of millions of years to evolve, unlike bacteria, which were the first life to appear on Earth, is extremely fragile to sudden and severe changes in the environment, and therefore are very prone to becoming extinct very easily and quickly within a short period of geological time, while microbial life is much more resilient to such changes.
[2] Drake equation
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