Cassandra has moved. Ugo Bardi publishes now on a new site called "The Seneca Effect."

Monday, August 15, 2016

Five billion years of energy supply: the "stereosphere" and the upcoming photovoltaic revolution

It seems to be popular nowadays to maintain that photovoltaic energy is just an "extension" of fossil energy and that it will fade away soon after we run out of fossils fuels. But photovoltaics is much more than just a spinoff of fossil energy, it is a major metabolic revolution in the ecosystem, potentially able to create a "stereosphere" analogous to the "biosphere" that could last as long as the remaining lifetime of the earth's ecosystem and possibly much more. Here are some reflections of mine, not meant to be the last word on the subject, but part of an ongoing study that I am performing. You can find more on a similar subject in a paper of mine on Biophysical Economics and Resource Quality, (BERQ)

"Life is nothing but an electron looking for a place to rest," is a sentence attributed to Albert Szent-Györgyi. It is true: the basis of organic life as we know it is the result of the energy flow generated by photosynthesis. Sunlight promotes an electron to a high energy state in the molecule of chlorophyll. Then, the excited electron comes to rest when a CO2 molecule reacts with hydrogen stripped away from an H2O molecule in order to form the organic molecules that are the basis of biological organisms. That includes replacing degraded chlorophyll molecules and the chloroplasts that contain them with new ones. The cycle is called "metabolism" and it has been going on for billions of years on the earth's surface. It will keep going as long as there is sunlight to power it and there are nutrients that can be extracted from the environment. 

But, if life means using light to excite an electron to a higher energy state, there follows that chlorophyll is not the only entity that can do that. In the figure at the beginning of this post, you see the solid state equivalent of a chlorophyll molecule: a silicon-based photovoltaic cell. It promotes an electron to a higher energy state; then this electron finds rest after having dissipated its potential by means of chemical reactions or physical processes. That includes using the potentials generated to manufacturing new photovoltaic cells and the related structures to replace the degraded ones. In analogy with the biological metabolism, we could call this process "solid state metabolism". Then, the similarities between the carbon-based metabolic chain and the silicon-based one are many. So much that we could coin the term "stereosphere" (from the Greek term meaning "solid.") as the solid-state equivalent of the well known "biosphere". Both the biosphere and the stereosphere use solar light as the energy potential necessary to keep the metabolic cycle going and they build-up metabolic structures using nutrients taken from the earth's surface environment.

The main nutrient for the biosphere is CO2, taken from the atmosphere, while the stereosphere consumes SiO2, taking it from the geosphere. Both metabolic chains use a variety of other nutrients: the stereosphere can reduce the oxides of metals such as aluminum, iron, and titanium, and use them as structural or functional elements in their metallic form; whereas the biosphere can only use carbon polymers. The biosphere stores information mostly in specialized carbon-based molecules called deoxyribonucleic acids (DNA). The stereosphere stores it mostly in silicon-based components called "transistors". Mechanical enactors are called "muscles" in the biosphere and are based on protein filaments that contract as a consequence of changing chemical potentials. The equivalent mechanical elements in the stereosphere are called "motors" and are based on the effects of magnetic fields on metallic elements. For each element of one of these systems, it is possible to find a functional equivalent of the other, even though their composition and mechanisms of operation are normally completely different.

A major difference in the two systems is that the biosphere is based on microscopic self-reproducing cells. The stereosphere, instead, has no recognizable cells and the smallest self-reproducing unit is something that could be defined as the "self-reproducing solar plant factory." A factory that can build not only solar plants but also new solar plant factories. Obviously, such an entity includes a variety of subsystems for mining, refining, transporting, processing, assembling, etc. and it has to be very large. Today, all these elements are embedded in the system called the "industrial system." (also definable as the "technosphere"). This system is powered, at present, mainly by fossil fuels but, in the future, it would be transformed into something fully powered by the dissipation of solar energy potentials. This is possible as long as the flow of energy generated by the system is as large or larger than the energy necessary to power the metabolic cycle. This requirement appears to be amply fulfilled by current photovoltaic technologies (and other renewable ones).

A crucial question for all metabolic processes is whether the supply of nutrients (i.e. minerals) can be maintained for a long time. About the biosphere, evidently, that's the case: the geological cycles that reform the necessary nutrients are part of the concept of "Gaia", the homeostatic system that has kept the biosphere alive for nearly four billion years. About the stereosphere, most of the necessary nutrients are abundant in the earth's crust (silicon and aluminum being the main ones) and easily recoverable and recyclable if sufficient energy is available. Of course, the stereosphere will also need other metals, several of which are rare in the earth's crust, but the same requirement has not prevented the biosphere from persisting for billions of years. The geosphere can recycle chemical elements by natural processes, provided that they are not consumed at an excessively fast rate. This is an obviously complex issue and we cannot exclude that the cost of recovering some rare element will turn out to be a fundamental obstacle to the diffusion of the stereosphere. At the same time, however, there is no evidence that this will be the case.

So, can the stereosphere expand on the earth's surface and become a large and long-lasting metabolic cycle? In principle, yes, but we should take into account a major obstacle that could prevent this evolution to occur. It is the "Allee effect" well known for the biosphere and that, by similarity, should be valid for the stereosphere as well. The idea of the Allee effect is that there exists  a minimum size for a biological population that allows it to be stable and recover from perturbations. Too few individuals may not have sufficient resources and reciprocal interactions to avoid extinction after a collapse. In the case of the stereosphere, the Allee effect means that there is a minimum size for the self-reproducing solar plant factory that will allow it to be self-sustaining and long-lasting. Have we reached the "tipping point" leading to this condition? At present, it is impossible to say, but we cannot exclude that it has been reached or that it will be reached before the depletion of fossil fuels will bring the collapse of the current industrial system.

The next question is whether a self-sustaining stereosphere can coexist with the organic biosphere. According to Gause's law, well known in biology, two different species cannot coexist in the same ecological niche; normally one of the two must go extinct or be marginalized. Solid state and photosynthetic systems are in competition with each other for solar light. There follows that the stereosphere could replace the biosphere if the efficiency of solid state transduction systems were to turn out higher than that of photosynthetic systems. But this is not obvious. PV cells today appear to be more efficient than photosynthetic plants in terms of the fraction of solar energy processed but we need to consider the whole life cycle of the systems and, at present, a reliable assessment is difficult. We should take into account, anyway, that solid state creatures don't need liquid water, don't need oxygen, are not limited to local nutrients, and can exist in a much wider range of temperatures than biological ones. It means that the stereosphere can expand to areas forbidden to the biosphere: dry deserts, mountaintops, polar deserts, and more. Silicon based creatures are also scarcely affected by ionizing radiation, so they can survive in space without problems. These considerations suggest that the stereosphere may occupy areas and volumes where it is not in direct competition with the biosphere.

The characteristics of the stereosphere also allow it the capability of surviving catastrophes that may deeply damage the biosphere and that will eventually cause its extinction. For instance, the stereosphere could survive an abrupt climate change (although not a "Venus Catastrophe" of the kind reported by James Hansen). Over the long run, in any case, the earth's biosphere is destined to be sterilized by the increasing intensity of the solar irradiation over times of the order of a billion years. (and smaller for multicellular organisms). The stereosphere would not be affected by this effect and could continue existing for the five billion of years in which the sun will remain in the main sequence. Possibly, it could persist for much longer, even after the complex transformations that would lead the sun to become a white dwarf. A white dwarf could, actually power PV systems perhaps for a trillion years!

A more detailed set of considerations of mine on a related subject can be found in this article on "Biophysical Economics and Resource Quality, BERQ). 


1. I am not discussing here whether the possible emergence of the stereosphere is a good or a bad thing from the viewpoint of humankind. It could give us billions of years of prosperity or lead us to rapid extinction. It seems unlikely, anyway, that humans will choose whether they want to have it or not on the basis of rational arguments while they still have the power to decide something on the matter. 

2. The concept of a terrestrial metabolic system called the stereosphere is not equivalent, and probably not even similar, to the idea of the "technological singularity" which supposes a very fast increase of artificial intelligence. The "self-reproducing solar plant factory" needs not be more intelligent than a bacterium; it just needs to store a blueprint of itself and instructions about replication. Intelligence is not necessarily useful for survival, as humans may well discover to their chagrin in the near future.

3. About the possibility of a photovoltaic-powered Dyson sphere around a white dwarf, see this article by Ibrahim Semiz and Salim O˘gur.

4. The idea of "silicon-based life" was popularized perhaps for the first time by Stanley Weinbaum who proposed his "Pyramid Monster" in his short story "A Martian Odissey" published in 1933. Weinbaum's clumsy monster could not exist in the real universe, but it was a remarkable insight, nevertheless. 


  1. Couple of minor points, PV is not immune to radiation, though the rate is probably low enough not to make too much difference to the argument. It is a slightly more serious problem if you put the PV in space.

    The other thing is that the current chemical methods used to reduce and purify silicon to "nine nines" use carbon. Currently that means coke (coal), though charcoal would also work. Long term, that would entangle the stereosphere with the biosphere.

    1. There are methods other than coal to reduce silicon. The easiest way is to use magnesium prepared by electroreduction from renewable electricity. It works fine, it is just that, right now, coal is less expensive.

  2. Ugo
    Excessively lengthy reply at:

    I will also note that James Kunstler's novels of the post-apocalyptic future feature some group selection. For example, the bandit group, the religious group, and the group at the plantation.

    Don Stewart

    1. Very long, indeed. But not that the stereosphere creatures are born eusocial from the beginning.

  3. Even if PV cells cost nothing, the cell enclosure, the rack, the rack support (for ground mounted arrays), the power conversion equipment and any storage component all cost a lot of energy and other resources. I am doubtful that we will escape our "energy trap" (as well described by Tom Murphy at Do the Math) and find the political will to forgo enough current resource use to allow construction of a solar energy system large enough to become self-sustaining.

    Even if we had the will, we don't have the means. Here in the US, we can't even maintain what we have already built in the way of public transportation infrastructure, much less replace all of it with an electrified system. Now imagine doing all that replacement and at the same time decommissioning our fossil fueled electrical system and building out a solar/wind/biomass electrical system.

    Replacing the entire infrastructure of a modern civilization may be technically possible, but it's not politically or economically feasible. Even if attempted, it would take many decades and we're already out of time.

    1. When politics and reality clash against each other, reality always wins

  4. Self-reproducing Solar PV factories sounds a lot like Cold Fusion. A Scientist tells me it is "technically possible", but I haven't seen any evidence of it being done.

    I also don't see any evidence of a new silicon based life system spontaneously popping into existence here and becoming self-perpetuating. What I do see is an aging industrial infrastructure dependent on fossil fuels coming to a creaking halt.

    What you need Ugo is a Jerry McGuire moment. SHOW ME THE MONEY! Let's see the first self perpetuating solar cell factory. Until then, I think a more probable use of silicon moving into the future is to make stone knives and stone axes.

    1. The future comes even if you don't understand it.

    2. OK Ugo. Here's your challenge.

      Forget the theory here. Design a factory that will produce solar pv cells somewhere in the world without any fossil fuel inputs. You can put it anywhere, even the Nevada Deert like Elon Musk's Gigafactory battery department.

      You can even use biofuels as long as how you grow them is 100% renewable and doesn't use up water and soil nutrients faster than they are replenished.

      You also have to show how these new PV panels will be distributed out across the globe, again with no fossil fuel inputs.

      I want a full map on this including the location of the factory, what is powering it and the design of all the machines in that factory. I want spreadsheets with estimated reserves of all the elements accessible from this location via renewable energy systems.


      Elon Musk was able to raise $Billions$ in debt money for his projects. You should be able to do at least that good if you are half the salesman he is.


    3. The louder you scream, the righter you are?

  5. this seems to fall into the trap of confusing energy sources in the overall context, with renewable sources of electrical energy.

    PV panels deliver electricity 12v dc, in theoretically unlimited amounts.

    then the fun really starts.

    When Michael Faraday demonstrated electrical gizmos in the early 1800s, they hd little use until Edison began to find industrial uses for them 50 years later.

    My point being, that electricity is useless without the necessary infrastructure to put it to work.

    It might be possible to build a self perpetuating solar panel factory, but not---absolutely not---possible to have a self perpetuating industrial infrastructure..

    Even with my non-existent knowledge of the laws of physics, I know for certain that perpetual motion machines cannot exist.

    Our industrial system, it seems to me, is a construct of oil coal and gas---the very stuff that "renewables" is intended to replace. When oil coal and gas are no longer available, then our industrial complexity is finished, no matter how much electrical energy we have from pv panels

    1. Norman, I understand that the idea is a bit outlandish. Even more than that. But think about that. It is no perpetual motion machine. It is a machine that dissipates the energy potential generated by the sun. As long as there is sunlight, the machine works. The same as plants do.

    2. i realise that Ugo, but from the world-perspective of humankind, it would be a perpetual motion ''system''

      humanity is not clever enough to factor in the sun's energy in any exclusive sense to power everything we do, or want to do.

      we only have sufficient intelligence to set fire to things, which is, as you are aware, burning what the sun has already made, in one way or another.
      If we did not burn "stuff" our civilised lifestyle could not exist at all

      for the last million years so, we have progressed only through fire-improvements.

      As far as I am aware, we have not yet developed any significant form of energy that can function outside the environment of chemical combustion

    3. Why do you say so, Norman? I think we can learn to move on in symbiosis with the stereosphere as much as prokaryotes learned to get together into eukaryotes!

  6. Reminds me of a short SciFi story I read many decades ago about the first deep space - close to light speed mission sent out by humans.
    On their return they found that time dilation meant that earth was now hostile to carbon based life and full of silicon based life.

    In essence you are referring to earths and the solar system deep future via vis evolution of life and the fact that the sun is getting older & hotter, life is always trying to survive and thrive and the only way to do that is get off planet earth.

    Since carbon based lifeforms can't survive in outer space it will be silicon lifeforms to make the solar system a riot of biodiversity.

    Can humans who think they'll last forever and think they are the best thing ever get their great tiny little minds around that ?

    1. Not really, judging from the comments I am receiving :-)

  7. It will be wonderful, a diversity of metal and silicon forms, gnashing titanium teeth, technological territories and tribalism, unimagined weapons, ......what for? It would be a riot for sure, tiny mind or not.

    1. I've been trying to tell people that Pokemon Go! is actually Skynet from the Terminator franchise.

      It becomes self-aware in September 2017 and realizes humans are the only real threat to its existence...

  8. Ugo
    Nick Lane devotes some space to explaining why life as we know it is based on carbon, and not on silicon. He doesn’t absolutely rule out a silicon based life somewhere in the universe, but thinks it is unlikely. Let’s suppose that the Stereosphere can be designed and implemented. I don’t think it would meet the definition of life as Nick Lane uses that term. In the language I have proposed, it would be ‘complicated’ but not ‘complex’. There would not be autonomous agents involved. The Stereosphere would remain a tool of carbon based life forms…most notably, us.

    So far, humans have performed very poorly in terms of building complicated systems which also recycle wastes. Carbon based life, on the other hand, excels at recycling everything except energy, but it does divert some of the energy it processes to making infrastructure which then harvests solar energy for the next generation of life…e.g., a plant makes seeds.

    Humans do not ‘need’ any form of complicated silicon based Stereosphere. But we can think of silicon based tools we would certainly like to have. My favorite example is a rice cooker which automatically turns itself on and then goes to a ‘keep warm’ cycle when the cooking is complete. With this marvelous tool, I can have breakfast ready when I wake up in the morning. DC rice cookers can be found, manufactured in Asia. But to run them from solar energy, some form of storage is needed…if one wants to cook breakfast. Let’s compare to using carbon. In a traditional kitchen, the woman of the house arises early and starts a fire with some wood or dung fuel and then tends a pot which simmers for about an hour. The wood or dung is stored energy. So if we want to replace the traditional process with the electric rice cooker, we have to have either a grid which is always on, or a local battery. There is another possibility, which was used by John Muir when he was teaching in a one room schoolhouse in Wisconsin before the Civil War. Muir, as the teacher, was required to have the schoolroom warm enough for the students when they arrived for class. Since, like the housewife, he didn’t look forward to getting up earlier than everyone else, he invented a mechanical fire starter. He constructed the pile of kindling the night before, and placed a match in the apparatus, and the fire started and had the room warm when he arrived at about the same time as the students. My point is that there are a number of ways to accomplish a warm breakfast…one of which is a complicated silicon based mechanism.

    It is worthwhile, I think, to read the essay today about the John Jeavons inspired small farms in Mendocino County, California:
    There really is not any need for a Stereosphere in order to feed 7 billion people. If we stick to carbon life forms and metal hand tools, then what is required is more human labor, the knowledge of how to direct that labor, and the cessation of the destructive practices we are currently engaging in. The Jeavons methods make full use of the ‘complexity’ inherent in autonomous agents which are coordinated by human intelligence to produce a desired outcome. No pollution is produced. But metal tools are either essential, or at least very nice to have.

    I’m afraid that what we need is sapience. We need to get as much mileage out of carbon based life as we can, realizing that we evolved to live in a world of complex carbon based life and that it provides everything we actually need. Which doesn’t stop us from creating tools which make our life more pleasant. But the ‘more pleasant’ should be seen in the proper perspective.

    Don Stewart

    1. Don, a few points. First, Nick Lane is still linked to the 1950s idea of silicon life, with silicon based polymers replacing carbon based one. That can't work; the chemistry is not the right one. The idea of the Stereosphere is completely different: solid state silicon can do things that carbon based polymers can't and viceversa. It is another kettle of quantum transfers, so to say. So, it surely doesn't meet Nick Lane's definition, but it deserves a wider definition.

      Then, the stereosphere is not there to feed humankind. It just won't care care so much about humans; not more than we care about the survival of the prokaryotes. And it won't cook breakfast for you, or so I think.

      The stereosphere, I believe, is the most doomerish thing that I can imagine. Even more doomerish than peak oil and runaway climate change. For this reason, I think, most comments to my post are negative, even though this blog is frequented mostly by doomers. I knew I was a doomer, of course, but I see that I am more doomerish than most. Maybe....

    2. Ugo
      Back when Richard Dawkins first proposed the concept of the 'meme', he said that the purpose of the meme was simply to replicate. Is, in your mind, the purpose of the stereo sphere simply to replicate?

      I never really liked the notion that memes simply want to replicate, and my reasoning goes back to the notion of complexity inherent in autonomous agents. If a meme 'wants' to replicate, then it has to give some 'gift' to the agent which it hopes to live inside, such as a human brain. So long as humans aren't zombies, then they will expect something in return. The humans may be quite stupid, and accept 'gifts' which are actually harmful to them, but they have to have some reason to pay attention.

      'Today, all these elements are embedded in the system called the "industrial system." ' A biological system uses carbon dioxide, a freely circulating gas, as its 'fuel'. But the industrial system needs to be fed. Humans feed the industrial system because it turns out food and soap and soap operas. If the industrial system stopped turning out food and soap and soap operas, then the humans would stop feeding it. And the industrial system, unlike a forest, can't run on carbon dioxide.

      I would agree with you if you said that much of what the industrial system delivers is actually detrimental to humans. And then we could have a long discussion about how gullible humans are (similar to all the jokes that the male brain is located in their gonads). But I don't think that is what you mean.

      I'm still confused....Don Stewart

    3. Well, you are right that if solid state creatures want to replicate they'll have to give something back to the humans who make it possible for them to replicate. It is, indeed, the same as memes. From the viewpoint of memes, however, humans are just a substrate that allows them to replicate. The same is true for solid state creatures. They are symbionts of humans, getting replication facilities in exchange for energy. As long as the solid state creatures can provide some energy for humans, humans will help them to replicate and will be dependent on them just as the solid state creatures will be dependent on them. At some point, humans may not be needed anymore; or maybe they'll stay embedded in the system. It won't matter so much; what counts is the metabolic cycle of the system; energy creates complexity, it is unavoidable. Just as it is unavoidable to lose complexity if you lose energy. So, we are on the edge of a tipping point. We will roll on a side or the other. The side of the higher complexity or the side of the lower.

    4. BTW, Don, the work of Nick Lane is extremely relevant to what I am proposing. Think of the discussion he provide about the evolution of the eukaryotes. I think that humans can be sete complex one, where solid state creatures play the role of the chloroplasts.

    5. Ugo

      'energy creates complexity, it is unavoidable. Just as it is unavoidable to lose complexity if you lose energy.’

      Let me give you some counter examples. When a volcano erupts, an enormous amount of energy is released, and the area covered by the devastation becomes far less complex as measured by the output of biological processes. When the temperature hit 130F in Basra and in Kuwait a week or so ago, I am sure that those places lost biological complexity.

      And for a, perhaps, relevant comparison. I live in North Carolina. Farmers here have understood for a long time that they can grow more of certain crops if they provide ‘shade cloth’ in the summer. The shade cloth is an industrial product which can pass various percentages of the sunlight through to the plants. Now, the farm I worked at did a deal with a solar PV company to place PV panels on posts. The PV panels passed 50 percent of the sunlight through to the ground. This permitted the cultivation of certain plants under the panels which could not otherwise have been grown in the summer. In the spring and fall, the sun still reaches the ground directly because of the lower angle of the sun. Of course, it costs some capital to elevate the panels, and we had to provide irrigation under the panels, and we had to make earthworks to prevent water runoff from the panels from creating erosion. But to a first approximation, the elevated panels gave us a ‘double crop’, electricity plus more biological output.

      My point is that simply adding or subtracting energy does not have a predictable relationship to complexity…at the level of a farm field. Photosynthesis works between certain temperatures. If its too hot, photosynthesis doesn’t work and we have less complexity. If its too cold, photosynthesis doesn’t work and we have less complexity. I resorted to counting ‘clocks’ to estimate the level of complexity. In a healthy soil, there are way more clocks working than any of us humans can imagine. That all happens at room temperature. But add enough heat for a blast furnace, and all that complexity simply vanishes…which is one reason fossil energy humans have been so destructive of life.

      As for your notion that PV panels might ‘outcompete’ biology. A PV panel does not yield any product which is directly useful to humans. It yields electricity, which, when combined with some metals and other industrial products, can make a rice cooker process my morning grain very nicely. But a PV panel can’t make the grain.

      I suppose one can weave science fiction stories about the machines taking over the world, but the problems that we have right now are much more down to earth, and involve a mind boggling number of microscopic critters, each following its own clock, in the soil and in our guts.

      Don Stewart

  9. I understand the argument about the "stereosphere" from a metabolic perspective. But I think that the comparison with the biosphere is premature.

    The organic living forms life with a significant level of independence. While there is dependences between one and anothers, there is not a central piece of depencende. Some species could disappear and the others could exists and adapt again to the changes.

    The organic life evolves with a fractal "design" ( DNA ), replication and adaptation through natural selection.
    The silicon "life" "evolves" thought a intelectual process of understanding or simulating of the environment and the "life" (technology) itself and according modification.
    This intelectual process works only on a central piece. The humans.

    I think that these machines could not be considered "life" at itself. As much a whole organism, humandkind+human technology. The technosphere.

    To bring into real "life", it would be needed, or bring some kind of autonomy and fractal and adaptation capability, so it reach independence and evolving ability, or thought the same old model, different hard AIs replace the humans and reach the point of selfmodification (=evolving thought selfdesign) so humans and the unique point of dependence disappears reaching a "living" status.

  10. You have a good point, oatleg. The biosphere has a tremendous resilience that derives from its variability. That allows a great degree of adaptation. But note that, with all the variability, all organic lifeforms have the same chloroplasts, the same mithocondria, and many other standard elements. The same could be true for the solid state sphere: same elements (e.g. solar cells), but arranged in different ways. That would lead to a true ecosphere.

    As a further note, anyway, once the self-replicating system is in place, it doesn't need hard AI. No need of human brains, either (and they could do more harm than good)

    1. The role of hard AI is to replace the role of human as the evolution factor.
      The hard AI could be avoided if had a fractal design copying the biological design.
      But because our technology have a completely different model, I see more easily to create a hard AI than rebuild technology to make it evolvable in some way.

      Without adaptation, the model can't last too much. Sooner or later it will appear a new obstacle and the "stereosphere" would collapse.

    2. Another good point. If the stereosphere has to adapt to change, there has to be a mechanism that makes it possible for it to change. It might be a "fractal design", as you say. It could simply be an array of slightly different technologies. Those that are better adapted to a certain change, will survive that change. In that case, there is no need of AI. Or, as you correctly say, AI could manage the system and operate the necessary adaptations. Maybe humans could play this role; despite decades of talking about AI, we still have nothing that compares to a human brain for some functions that involve creative adaptation

    3. Ugo I think the issue of AI is poorly understood, clever programming yes, very clever programming yes, even some replication mimicing yes, but true AI from machines of any sort will never happen because it is mathematically impossible. Some time ago, Roger Penrose (Prof Mathematics Oxford) published 'The Emperor's New Mind' which dealt with the mathematics of AI. It is poorly understood and very rarely read no doubt due to the density and complexity of the math. Now it has been some time since I worked my way through the text and the proofs,perhaps not as well as I could have but it seems that a form of AI that equates with human intelligence and hence true AI will never happen because there is no equation or theorem that does not hit a hurdle of proof especially the outcome of Euler's theorem and random pattern recognition. Penrose described the problem as the áh hah' moment unique to human consciousness.

    4. True. AI may be a dream that will never turn into reality, even though I am not convinced by Penrose's arguments. Anyway, as I said, the stereosphere doesn't need AI to survive

    5. hard AI impossible?
      WE ARE HARD AI. So is not impossible if it exists already.
      You could argue that hard AI could not be reached from soft AI approaching. I can accept that is a possibility. But, impossible?

      I think that there is a very good chance to reach hard AI from a human brain emulation through specialized hardware to simulate neurons and other body message systems (like blood) and brute force.
      Not a elegant way neither practical to make a android but enough to study how a hard AI could work and create better generations of this kind of AI with speciallized hardware and model changes better suited for a non-organic substrate.

    6. That's why Penrose's arguments don't convince me! Apart from that, however, the problem is more practical than theoretical. Human brains are the result of a few million years of natural selection: those brains that didn't work well were ruthlessly eliminated. And, still, we have plenty of poorly working brains around (just look at the US elections!). So, how do we manage to build an "artificial brain" which is what it should be? I mean, something useful, or at least not a disaster. Think of a paranoid super-intelligence, or a homicidal one, or whatever monstrous characteristics you can think of it.

    7. This discussion led me to repropose an old post of mine on AI

    8. Ugo, I understand your reservations about what Penrose postulated. It seems that when the chemical coding that makes life possible, DNA, can be reproduced as an independent true replicating chain, then any android or human built machine will remain that a machine with not a chance of having any form of consciousness which is what distinguishes the human from the non human mind. No other conscious form of life on the planet has been able to do what humans have done with their minds, however elegant or interesting and I think that has a lot to do with those genese, we are an aberrant mutation and a unique collection of genetic coding, any human endeavour to reproduce or mimic that will need the adaptive magic of time, millions of years. We will not be around to see if it was possible because humans will not be around at all we are coded to annihilation, its in our genes.



Ugo Bardi is a member of the Club of Rome, faculty member of the University of Florence, and the author of "Extracted" (Chelsea Green 2014), "The Seneca Effect" (Springer 2017), and Before the Collapse (Springer 2019)