Field of Science

Life. Distributed.

One of my favorite science fiction novels is “The Black Cloud” by Fred Hoyle. It describes an alien intelligence in the form of a cloud that approaches the earth and settles by the sun. Because of its proximity to the sun the cloud causes havoc with the climate and thwarts the attempts of scientists to both study it and attack it. Gradually the scientists come to realize that the cloud is an intelligence unlike any they have encountered. They are finally successful in communicating with the cloud and realize that its intelligence is conveyed by electrical impulses moving inside it. The cloud and the humans finally part on peaceful terms.

There are two particularly interesting aspects of the cloud that warrant further attention. One is that it’s surprised to find intelligence on a solid planet; it is used to intelligence being gaseous. The second is that it’s surprised to find intelligence concentrated in individual human minds; it is used to intelligence constantly moving around. The reason these aspects of the story are interesting is because they show that Hoyle was ahead of his time and was already thinking about forms of intelligence and life that we have barely scratched the surface of.

Our intelligence is locked up in a three pound mass of wet solid matter. And it’s a result of the development of the central nervous system. The central nervous system was one of the great innovations in the history of life. It allowed organisms to concentrate their energy and information-processing power in a single mass that sent out tentacles communicating with the rest of the body. The tentacles are important but the preponderance of the brain’s capability resides in itself, in a single organ that cannot be detached or disassembled and moved around. From dolphins to tigers and from bonobos to humans, we find the same basic plan existing for good reasons. The central nervous system is an example of what’s called convergent evolution, which refers to the ability of evolution to find the same solutions for complex problems. Especially in Homo sapiens, the central nervous system and the consequent development of the neocortex are seen as the crowning glory of human evolution.

And yet it’s the solutions that escaped the general plan that are the most interesting in a sense. Throughout the animal and plant kingdom we find examples not of central but of distributed intelligence, like Hoyle’s cloud. Octopuses are particular fascinating examples. They can smell and touch and understand not just through their conspicuous brains but through their tentacles; they are even thought to “see” color through these appendages. But to find the ultimate examples of distributed intelligence, it might be prudent not to look at earth’s most conspicuous and popular examples of life but its most obscure – fungi. Communicating the wonders of distributed intelligence through the story of fungi is what Merlin Sheldrake accomplishes in his book, “Entangled Life”.

Fungi have always been our silent partners, partners that are much more like us than we can imagine. Like bacteria they are involved in an immense number of activities that both aid and harm human beings, but most interestingly, fungi unlike bacteria are eukaryotes and are therefore, counterintuitively, evolutionarily closer to us rather than to their superficially similar counterparts. And they get as close to us as we can imagine. Penicillin is famously produced by a fungus; so is the antibiotic fluconazole that is used to kill other fungal infections. Fungal infections can be deadly; Aspergillus forms clumps in the lungs that can rapidly kill patients by spreading through the bloodstream. Fungi of course charm purveyors of gastronomic delights everywhere in the world as mushrooms, and they also charm purveyors of olfactory delights as truffles; a small lump can easily sell for five thousand dollars. Last but not the least, fungi have taken millions of humans into other worlds and artistic explosions of colors and sight by inducing hallucinations.

With this diverse list of vivid qualities, it may seem odd that perhaps the most interesting quality of fungi lies not in what we can see but what we can’t. Mushrooms may grace dinner plates in restaurants and homes around the world, but they are merely the fruiting bodies of fungi. They may be visible as clear vials of life-saving drugs in hospitals. But as Sheldrake describes in loving detail, the most important parts of the fungi are hidden below the ground. These are the vast networks of the fungal mycelium – the sheer, gossamer, thread-like structure snaking its way through forests and hills, sometimes spreading over hundreds of square miles, occasionally being as old as the neolithic revolution, all out of sight of most human beings and visible only to the one entity with which it has forged an unbreakable, intimate alliance – trees. Dig a little deep into a tree root and put it under a microscope and your will find wisps of what seem like even smaller roots, except that these roots penetrate into the trees roots. The wisps are fungal mycelium. They are everywhere; around roots, under them, over them and inside them. At first glance the the ability of fungal networks to penetrate inside tree roots might evoke pain and invoke images of an unholy literal physical union of two species. It’s certainly a physical union, but it may be one of the holiest meetings of species in biology. In fact it might well be impossible to find a tree whose roots have no interaction with fungal mycelium. The vast network of fibers the mycelium forms is called a mycorrhizal network.

The mycorrhizal networks that wind their way in and out of tree roots are likely as old as trees themselves. The alliance almost certainly exists because of a simple matter of biochemistry. When plants first colonized land they possessed the miraculous ability of photosynthesis that completely changed the history of life on this planet. But unlike carbon which they can literally manufacture out of sunlight and thin air, they still have to find essential nutrients for life, metals like magnesium and other life-giving elements like phosphorus and nitrogen. Because of an intrinsic lack of mobility, plants and trees had to find someone who could bring them these essential elements. The answer was fungi. Fungal networks stretching across miles ensured that they could shuttle nutrients back and forth between trees. In return the fungi could consume the precious carbon that the tree sank into its body – as much as twenty tons during a large tree’s lifetime. It was the classic example of symbiosis, a term coined by the German botanist Albert Frank, who also coined the term mycorrhiza.

However, the discovery that fungal networks could supply trees with essential nutrients in a symbiotic exchange was only the beginning of the surprises they held. Sheldrake talks in particular about the work of the mycologists Lynne Body and Suzanne Simard who have found qualities in the mycorrhizal networks of trees that can only be described as deliberate intelligence. Here are a few examples: fungi seem to “buy low, sell high”, providing trees with important elements when they have fallen on hard times and liberally borrowing from them when they are doing well. Mycorrhizal networks also show electrical activity and can discharge a small burst of electrochemical potential when prodded. They can entrap nematodes in a kind of death grip and extract their nutrients; they can do the same with ants. Perhaps most fascinatingly, fungal mycelia display “intelligence at a distance”; one part of a huge fungal network seems to know what the other is doing. The most striking experiment that demonstrates this shows oyster mushroom mycelium growing on a piece of wood and spreading in all directions. When another piece of wood is kept at a distance, within a few days the fungal fibers spread and latch on to that piece. This is perhaps unsurprising. What is surprising is that once the fungus discovers this new food source, it almost instantly pares down growth in all other parts of its network and concentrates it in the direction of the new piece of wood. Even more interestingly, scientists have found that the hyphae or tips of fungi can act not only as sensors but as primitive Boolean logic gates, opening and closing to allow only certain branches of the network to communicate with each other. There are even attempts to use fungi as primitive computers.

This intelligent long-distance relay gets mirrored in the behavior of the trees that the fungi form a mind meld with. One of the characters in Richard Powers’s marvelous novel “The Overstory” discovers how trees are whispering hidden signals to each other, not just through fungal networks but through ordinary chemical communication. The character Patty Westford finds out that when insects attack one tree, it can send out a chemical alarm that alerts trees located even dozens of meters away of its plight, causing them to kick their own repellant chemical production into high gear. Meeting the usual fate of scientists with novel ideas, Westford and her ideas are first ignored, then mocked and ostracized and ultimately grudgingly accepted. But the discovery of trees and their fungal networks communicating through each other and through the agency of both chemicals and other organisms like insects is now generally accepted enough to become part of both serious scientific journals and prizewinning novels.

Fungi can also show intelligent behavior by manipulating our minds, and this is where things get speculative. Psilocybin and LSD have been used by shamans, hippies and Silicon Valley tech entrepreneurs over thousands of years. When you are familiar with both chemistry and biology it’s natural to ask what might be the perceived evolutionary utility of chemical compounds that bring about changes in perception that are so profound and seemingly liberating as to lead someone like Aldous Huxley to make sure that he was on a psychedelic high during the moment of his death. One interesting clue arises from the discovery of these compounds in the chemical defense responses of certain fungi. Clearly the microorganisms that are engaged in a war with fungi – and these often include other fungi – lack a central nervous system and have no concept of a hallucination. But if these compounds are found as part of the wreckage of fungal wars, maybe this was their original purpose, and the fact that they happen to take humans on a trip is only incidental.

That is the boring and likely explanation. The interesting and unlikely explanation that Sheldrake alludes to is to consider a human, in the medley of definitions that humans have lent themselves to, as a vehicle for a fungus to propagate itself. In the Selfish Fungus theory, magic mushrooms and ergot have been able to hijack our minds so that more of us will use them, cultivate and tend them and love them, ensuring their propagation. Even though their effects might be incidental, they can help us in unexpected ways. If acid and psilocybin trips can spark even the occasional discovery of a new mathematical object or a new artistic style, both the fungi and the humans’ purpose is served. I have another interesting theory of psychedelic mushroom-human co-evolution in mind that refers to Julian Jaynes’s idea of the bicameral mind. According to Jaynes, humans may have lacked consciousness until as recently as 3000 years ago because their mind was divided into two parts, one of which “spoke” and the other “listened”. What we call Gods speaking to humans was a result of the speaking side holding forth. Is it possible that at some point in time, humans got hold of psychedelic fungi and they hijacked a more primitive version of the speaking mind that allowed it it to turn into a full-blown voice inside the other mind’s head, so to speak? Jaynes’s theory has been called “either complete rubbish or a work of consummate genius, nothing in between” by Richard Dawkins, and this might be another way to probe whether it might be true for a reason.

It is all too easy to anthropomorphize trees and especially fungi, which only indicates how interestingly they behave. One can say that “trees give and trees receive”, “trees feel” and even “trees know”, but at a biological level is this behavior little more than a series of Darwinian business transactions, purely driven by natural selection and survival? Maybe, but ultimately what matters is not what we call the behavior but the connections it implies. And there is no doubt that fungi, trees, octopuses and a few other assorted creatures are displaying a unique type of intelligence that humans may have merely glimpsed. Distributed intelligence clearly has a few benefits over a central, localized one. Unlike humans who are unlikely to live when their heads are cut off, newts can regrow their heads when they get detached, so there’s certainly a survival advantage conferred by not having your intelligence organ be one and done. This principle has been exploited by the one form of distributed intelligence that is an extension of human beings and that has taken over the planet – the Internet. Among many ideas that are regarded as the origins of the Internet, one was conceived by the defense department which wanted to built a communications net that would be resilient in the face of nuclear attack. Having a distributed network with no one node being a central node was the key. Servers in companies like Google and Facebook are also constructed in such a way that a would be hacker or terrorist would have to take out several and not just a few in order to measurably impair the fidelity of the network.

I also want to posit the possibility that distributed systems might be more analog than central ones and therefore confer unique advantages. Think of a distributed network of water pipes, arteries, traffic lanes or tree roots and fungal networks and one has the image in mind of a network that can almost instantaneously transmit changes in parameters like pressure, temperature and density taking place in one part of the network to another. These are all good examples of analog computation, although in case of arteries, the analog process is built on a substrate of digital neuronal firing. The human body is clearly a system where a combination of analog and digital works well, but looking at distributed intelligence one gets a sense that we can optimize our intelligence significantly using more analog computing.

There is no reason why intelligence may not be predominantly analog and distributed so that it becomes resilient, sensitive and creative like mycorrhizal networks, being able to guard itself against existential threats, respond to new food and resource locations and construct new structures with new form and function. One way to make human intelligence more analog and distributed would be to enable human-to-human connections through high-fidelity electronics that allows a direct flow of information to and from human brains. But a more practical solution might be to enable downloading brain contents including memory into computers and then allowing these computers to communicate with each other. I do not know if this advance will take place during my lifetime, but it could certainly bring us closer to being a truly distributed intelligence that just like mycorrhizal networks is infinitely responsive, creative, resilient and empathetic. And then perhaps we will know exactly what it feels like to be a tree.

1 comment:

  1. Great post, thanks. I enjoy your breadth of perspective and philosophical outlook a great deal.
    Just a note on convergent evolution. One of the best examples seems to me the swallow and the swift. They are similar because they have evolved a similar life style and not because they are close (phylogenetic) relations. Another example that comes to mind is the human and octopod eye. Although they are similar in many ways, they have evolved from different ancestor organs and are thus not 'related' organs.
    In contrast, the brains of all mammals (and even all vertebrates for that matter) are similar because they all share a common ancestor. Thus, the brains of different vertebrates is not a case of convergent evolution as far as I can see.


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