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The Biological Universe

I'm finishing up the new book The Biological Universe, by emeritus evolutionary biologist Wallace Arthur. I made some critical comments on my sometime blog The Gyromantic Informicon [q.v.] about this, but what follows is my specific take on what he calls his Huge Hypothesis, summing up his view of the entire subject. If the general subject of life in the universe doesn't really capture your imagination, you might want to skip the rest of this. 

He proposes that the evidence and reasonable inference supports the following "Huge Hypothesis." I paraphrase a good deal and add in some explanatory comments. These are, to use Thomas Huxley's phrase, "in the indicative," rather than the "potential," even though strictly speaking some of this has to be considered speculative. Most of it is pretty widely accepted in the scientific community today; the additional points I add at the end less so, but I believe they follow logically and are of the same order of certainty; namely, not certain but probable. 

• Life first evolved somewhere in the universe not much later than 10 billion years ago.   [Arthur restricts himself to the observable universe, a space about 93 billion light years across in all directions with us at the center and containing approximately 2 trillion galaxies; the entire universe is much, much larger and, applying the principles of isotropy and homogeneity on large scales, is presumably all much the same]. 
• The oldest instance of the origin of life was overwhelmingly likely to have been on a planet in a galaxy at great distance from the Milky Way, just because there are literally something like a trillion candidate galaxies, each containing hundreds of billions of planets, in the observable universe ("OU" for short). 
• Since that time, there has been a steady increase in the number of locales where life has originated and thrived for a time, and at least a good proportion of them continue to have life at the present epoch, such that some form of life is now relatively common in the universe. 
• QED, the number of planets in the OU with some form of life, mostly limited to microbial life, is many trillions. (Note: every spiral galaxy, and probably many other types of galaxies, as well, have billions to more than a trillion planets, and a typical spiral galaxy like the Milky Way has hundreds of billions of rocky planets situated in the "habitable zone" of their stars where liquid water is possible. The same should be true of most galaxies).
  
  [Arthur includes an additional bullet point, that some systems have more than one inhabited planet; but I regard that as superfluous to the argument].
  
  
• Most or all of the life in the universe is chemically based on carbon compounds. (There are many reasons for including this inference, which I consider to be quite ironclad, but I won't go into it here. My own surmise is that you could correctly say "Essentially all". Fortunately, nucleosynthesis in stars results in the production of a good deal of carbon). 
• Add-in, not included by Arthur:  All, or nearly all, life in the OU has evolved a genetic information recording system that functions analogously to the nucleic acid system that evolved on Earth, although specific details vary considerably.   
  
• Far and away most life in the OU is constructed of cells, although, again, the exact architecture varies considerably. 
• Most life-bearing planets in the OU host only microbial life (single cell or small-aggregates of cells).
• A large number (but proportionally fewer) of the life-bearing planets in the OU also host multicellular life.
• At least some proportion of the biospheres that have evolved multicellular life have evolved "complex" multicellular organisms that conduct photosynthesis to utilize light energy directly (similar to Plants and other photosynthesizer macrobiota on Earth, such as "brown algae"); or that assume roles comparable to those of the Fungi and Animal kingdoms in the Earth biosphere (symbionts and parasites). 
• On at least some of the biospheres that have evolved such "complex" multicellular "animals," some of them have evolved advanced motility, including analogs to skeletal (including exoskeletal) structure, musculature, nervous systems, and the beginnings of intelligence, in the sense of directed control by a "brain." 
• With all intermediate levels occurring in numbers, some portion of the biospheres that have evolved such complex animal life have proceeded to the evolution of human-level intelligence, although exactly how that manifests varies considerably. 

This is where Arthur's Huge Hypothesis ends, but therein lies my principal criticism of his thesis. I think he overestimates the numbers somewhat, especially of the last phase, but I don't disagree with any of the above. I suspect there may be some side roads that lead to unanticipated variants of the types of life we are familiar with, but the main ideas here I believe are sound. But I think they really miss the mark when it comes to a reasonable anticipation of our possible future, which, necessarily, means something analogous to what is already the state of being elsewhere, where human-level intelligence already evolved, in some cases no doubt, a very long time ago indeed. So I would add the following additional levels of development, further along in the sequence. 

• Some portion of human-level intelligent life develops external symbolic manipulation analogous to language, and eventually culture, and then advanced science and technology. This gives organisms the ability to direct their own evolution from this point, at least to an extent. 
• Some portion of the technological species develop artificial biohabitats and are no longer confined to the surfaces of their planets of origin. [I would adventure that we are on the cusp of this development, and that there is no guarantee we will proceed to it; presumably frequently in the past and future, beings at this level do not make this transition successfully or never even try, for whatever reason]. 
• Once at the level of "space-dwelling," most of the technological species proceed to colonize their star systems and later other stars, and to spread the form of life that originated on their planet to vast numbers of other locations in space, including but not limited to planets that did not and might never evolve life on their own, such that over time most of the life in the universe exists elsewhere than the planetary surfaces where it originated. 
• There is virtually no natural limit to the expansion of life under the direction and impetus of intelligence; the future of the OU is for life to encompass a greater and greater proportion of the available locations where sustaining life is possible until some saturation level is reached in the distant future. [Comment: even if this development is relatively rare, it is a threshold; once it occurs, it tends to lead to a permanent change in the course of the development life over a very wide region of space, potentially including multiple galaxies before bumping into others similarly situated, because plausible rates of expansion of such extended biospheres entail small fractions of the age of the planets and galaxies in which they originate. So, ultimately, if this phase occurs at all, it will tend to fill all the available space everywhere].

We are directed by current modes of scientific thought to shun all teleology, but I think it's fair to assess that the "function" of advanced human-level intelligence (and beyond) is to make something like the final three stages of my "even huger hypothesis" possible. I envision an "Age of Life" that is just getting underway in a universe that will eventually be quite literally filled with life. 

I hasten to emphasize the obvious: most of the last two phases mentioned above lie in the future, in most locales. If some regions of the OU have advanced to the level of galaxy-spanning civilizations already, this would likely be apparent in some way were it already common, at least in the relatively nearby regions, say out to 500 million light years. Because, of course, if such developments were to have occurred at that distance, say, 450 million years ago, we would not see any evidence, because the light from that time would not have reached us yet. There could well be the first instances of extremely advanced civilization in parts of space that we just can't see yet. (This assumes, as I think is reasonable, that engineering on a literally galactic scale would change the quality of enough of the light coming from natural luminous sources that the presence of artificial technology would be inferrable). 

Wallace Arthur's «The Biological Universe» and the role of human-level intelligence in the future of life in the universe

This is not really a review of the new book The Biological Universe, by Wallace Arthur; just a few critical points. 

First, Arthur hardly mentions the Fermi conundrum, which, in its fully evolved form, is one of the principal pieces of evidence for the inference that intelligent life, and, probably, what he doesn't like to call "complex" life, are, respectively somewhere between very, very to extremely rare; and at least quite rare. Fermi isn't even circumstantial evidence for the the rarity of complex life per se, except insofar as the presumption is that if life elsewhere reaches the level of say the Cambrian era on Earth (highly complex, long-term stable biosphere with high degree of penetration of all habitats on the planet), it is probably something on the order of at least 1 to 3% likely to evolve to human level intelligence. And if you assume such intelligence is even 1% likely to survive to the level where it is a spacefaring and spacedwelling species, capable of spreading its particular architecture of life far and wide in at least one galaxy, then if you assume that life of this kind is relatively common (as Arthur does), the numbers still don't add up if intelligent life arising even on these life bearing worlds isn't also exceedingly rare. Note that the number of planets with microbial life at any given time is assumed by Arthur, plausibly, to be something like 10 million planets in a galaxy the size of Milky Way  (which is still something like 0.0001% of all planets in the galaxy). 

 

Bottom line, you have to acknowledge that the evidence best supports not a rare life or even extremely rare "complex" life but certainly a very rare human-level intelligence condition. Arthur doesn't really disagree with this but he doesn't address it well at all. The inferential evidence of rare intelligence as an implication that extremely robust and complex life biospheres may be more unlikely than he seems to believe is ignored. 

His main thesis is that the "rare Earth" view is wrong,* and he disputes the very concept of "complex" life, but ultimately his main evidence for this is the same old Earth-centric view of the probability of various "filters" in the evolution of life. Having said that, he did convince me that both eukaryotism (if that's a word)**, or some analogue of it, and photosynthesis are probably closer to inevitable than they are to being filters, in the sense of potential stumbling blocks to the evolution of more "complex" life. As is, apparently, the abiogenic origin of life itself. My best guess is that microbial life is at least as common as Arthur thinks it is, and that the principal reason that very robust biospheres like Earth's remain quite rare, and climax human-level intelligent-life conditions even moreso, is that these or other critical developments for the evolution of macrobiota and subsequently intelligence actually are relatively unlikely, and the universe just isn't quite old enough yet for them to manifest widely. Surely, we can surmise that as vast as the universe is known to be, as here on Earth, complex biospheres, including ones which have given rise to human-level intelligent beings, exist elsewhere in large numbers. But, and this is key from the human perspective, they are apparently very widely scattered. 

My last, and perhaps actually chief, criticism, is as follows. Arthur all but totally ignores the possibility that human-level intelligence itself, when it does evolve, is absolutely critical to the future history of biospheres from which it evolves. He blithely assumes that humans and their descendants will simply become extinct before advancing to a stage where they are spreading terriform*** life elsewhere in the Galaxy, and that we will never exceed the bounds of our own Solar system. My belief, which I think is reasonable inference not just gut feeling, is that if and only if the human species survives the current era, the spread of terriform life far beyond the confines of one star system will be extremely likely. I base this on two assumptions:  if we survive a few centuries, we will likely succeed in building self sustaining space habitats that contain more terriform biomass than the surface of the Earth, eventually. Further, we will likely figure out how to construct some kind of practical interstellar transportation (which could be generation ships or suspended animation, or, just possibly, quite fast in terms of fraction of light speed, drives). I take both of these developments to be generally more or less inevitable if technological societies evolve to the level where they can easily travel in and dwell in space near their home stars. The question then becomes how likely those developments actually are to occur, which translates to how prevalent technological societies are in the universe. And on that point, I hold forth two maxims. 1. Humans are very ingenious; our minds have evolved to the point that there really are no limits on what possible technology we can figure out and build in time; and 2. there is absolutely nothing in this scenario that is impossible. The same maxims should apply with respect to other human-level intelligent beings elsewhere in the universe. 

Arthur mentions virtually nothing discussed in this last paragraph. But they are crucial to his subject, which does purport to discuss the future of life. And if you generalize to other comparably situated intelligent species in a wider universe, the inference that even if we fail others will succeed is hard to avoid. 

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*Reference is to the influential but widely critiqued book, Rare Earth, Why Complex Life is Uncommon in the Universe, by Peter D. Ward and Donald Brownlee (2000, 2003).

** Referring to the evolution of nucleated cells, widely believed to be necessary for the evolution of so-called "macrobiota."

***As far as I know this is an original coinage. The term is meant to refer to life originating on, or descended from life originating on, Earth. 

 

Red Dwarf stars and the Long Range Future of Life in the Universe

Posted this as an answer to a question, but it might conceivably be of interest to some people on its own.

Alien civilizations are very unlikely to evolve on a planet orbiting a red dwarf, for several reasons. First, the habitable zone is small and so close to the star, which by nature is prone to bright flares that can increase the brightness, including in dangerous ionizing wavelengths, by orders of magnitude within short periods of time. These flares are likely to make life very precarious if not impossible on any planets in the zone. Further, planets found this close to such stars will generally be tidally locked, with one face always facing the star. A third problem is that the peak radiation from such stars is in the infrared, so it isn't even clear that photosynthesis could successfully evolve and function in a biosphere on such a planet.

Interestingly, however, there is no real reason that life originating from outside such a system (and these stars constitute about 70% of all stars) could not be transported there artificially, and provided with habitats that would use the light of the star as an energy source. I happen to believe that the Age of Life is just beginning in the universe at large, and the role of intelligent species in assisting the seeding of life in places where it (including its intelligent forms) can exist but is unlikely to spontaneously evolve, will be quite simply incalculably important for the long range future of life in the universe in general.

Since red dwarfs typically have lifetimes in the hundreds of billions to a trillion years, these stars are likely to be the sites of surviving life for far longer than the universe has existed hitherto.

The protein coding problem... one of the great conundra of biology... SOLVED

This is a sure-thing Nobel Prize and may turn out to be the most important scientific discovery in years. Essentially, we now finally know the language that life uses to create proteins, and how to predict the shape, function, and other properties of proteins that any given genetic code text will produce. This is enormously important, and may be the key to solving biological materials shortages, creating medicines from raw materials without having to laboriously process biological resources, and many other as yet unknown developments. This is comparable to the discovery of CRISPR Cas=9 (which google if you don't know what that is)... maybe more important. And one of the most amazing things is that this development was so computation- intensive that it was not actually human intelligence that solved the fundamental problems, but AI, guided by humans. It's a brave new world. 

https://www.vox.com/future-perfect/22045713/ai-artificial-intelligence-deepmind-protein-folding

Sous vide (something other than politics!)

 A little over a year ago I bought a sous vide* bath, sous vide machine, vacuum sealer, and vacuum sealer bag rolls. (The machine is essential, they're about $140-200; the bath, essentially a plastic box with a lid, is not, you can use a stock pot. I recommend the vacuum sealer; the immersion method with ziploc bags is a pain and tends to leak, with bad results). 

At first I only used it to cook perfectly medium rare steaks, to be seared afterwards. (It actually works to sear them before, and is easier). 1 hour at 143°F and perfect color straight through. So I didn't use it that much. But I've discovered cooking  brisket or chuck for 7 or 8 hours at 145° creates perfect meat for pot roast; tender but actually still slightly rare; mix it into already cooked pot roast gravy and vegetables, which take much less time, and it's the best pot roast ever. 

And then there's turkey. We're just two people, so cooking a whole turkey, even the smallest ones you can get, is kind of impractical. So I buy the frozen bone-in breasts, which sometimes cost as little as $8 or $9 and make several meals or a whole bunch of sandwiches. And here's the thing. You can cook it for 3 hours at 165° and then put it in a very hot oven or broiler for 15 min., or you can even just skip that step; remove the skin, and just eat the meat, which is PERFECTLY cooked, moist, tender, and delicious. And the bones make excellent real turkey soup. 

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* Not italicized, it's now a two-word syntactical unit in English, like coup d'etat (without the acute accent, since we don't use diacritics in English). Pronounced "soo veed."