I spend probably too much of my time (and now yours) trying to work out the apparent differences between animate and inanimate arrangements of atoms. In practice it’s not at all hard to tell one from the other, even if a mass spectrometer would confirm that all the same atoms comprise the collections. Children easily differentiate one from the other. Isn’t that definitive?
In a similar vein, it’s not hard to tell a star from a brown dwarf, even though they have essentially identical compositions. The one having more than 8% the mass of our sun will ignite fusion and light up, while the one not “tall enough to go on the ride” will continue sulking as a dim, warm lump.
It’s not hard to tell the difference in behavior between a piece of paper fluttering to the floor and the exact same piece wadded tightly and dropping straight down. A clear sheet of glass or ice becomes an opaque white powder simply by crushing it thoroughly. A log looks and acts much differently before and after burning, even though no atoms were created or destroyed—most are dispersed as invisible gas. Arrangement matters.
But I want to poke a little deeper and identify an arrangement that we would never call animate, yet displays many of the hallmarks of Life. This is my clumsy attempt at doing so. The purpose is not to find an exact match in this example, because that’s impossible: identifying flaws is easy sport. Rather, this exercise provides a window that might allow our crippled imaginations to dimly grasp how Life might develop behaviors that appear purposeful in the context of evolutionary feedback. So, instead of focusing on imperfections, the challenge is: are you able to make out the shape beyond the distracting foreground fog? What new insights does this perspective offer? How might you build upon it and make it even better?
This is the first in a two-part series on what constitutes Life, as far as I can gather.
Traits of Life
Every living being comes from beings able to reproduce/replicate. Not all life can itself reproduce (ask a mule), but most can. Life adapts by genetic mixing and random mutation in feedback relation to demonstrated success (i.e., life evolves under selective influences). Life enacts proactive decisions that impact how it fares in the world. These decisions, too, are part of the great feedback mechanism called evolution that shapes not only morphologies, metabolism, mobility, dexterity, etc. but also decisions to be successful in an adaptive sense. Life collects resources from its environment in order to secure the atoms it needs to live and pass along its pattern. Life tends to be robust enough to mitigate a number of adverse circumstances: tolerating extremes in temperature, moisture, food availability, dangers, and damages.
The paragraph above lists an impressive set of capabilities, right? Clearly we won’t find rocks engaged in any of these activities. By no coincidence, internal structures of a rock are not even remotely as complex as those in living tissue. As I said, arrangement matters!
Land of Eternal Rain
I remember as a kid growing up in the 70s spending seemingly-interminable periods in the car while it rained and my mom did important things like shopping and putting items in lay-away. I would watch rivulets on the window, mesmerized by their antics: watching patterns emerge out of the pitter-patter. It’s a lot like being entranced by fire, which also seems to have a life of its own.
Earth is a land of eternal sunshine. By that, I do not mean that it is sunny at every moment in every location. But the sun has steadily shone on Earth for billions of years without even a single nanosecond of vacation. It’s a dependable, essentially eternal source of energy that powers Life.
For our thought experiment, we’ll imagine a land of eternal, steady rain. This rain will fall on a sloped piece of glass like a windshield. Rain is the resource, which accumulates. Beyond a threshold, globs migrate down the surface, snow-balling as they gather more “resource” in a sort of avalanche process. By having established a route, the next gathering is likely to execute the same path, or at least much of it. Depending on surface properties, slope, and rate of rainfall, rivulets may become essentially permanent, like little river-lets (ohhh…) sweeping water off the glass.
Self-Replication
I already hinted at one critical piece. Once a path has been forged through the randomness, that path is likely to be followed again. It may even become a semi-permanent structure. Think of the path as a blueprint, and the drops that race along as individual lives (moving from birth to death). The pattern is a standing pattern like a particular species—following a DNA blueprint—while individuals are expressed in that mold, flowing through the pattern.
Anyway, the essential feature is that a rivulet establishes conditions that make repetition of that particular pattern far more likely than a fresh start from scratch.
Measure of Success
If a rivulet (or more realistically, a set or network of rivulets) is not clearing the entire windshield, water will accumulate in neglected areas and something else will spring up to fill that niche. It will have to navigate the existing space, either replacing/disrupting other rivulets, merging with them, or failing to establish as a repeating phenomenon: a one-off trial.
Success is assessed by how effectively the windshield is cleared by the set of rivulets. The patterns will keep changing until well-matched to the steady input. A successful rivulet—or ecology of rivulets—will have established an efficient and essentially complete assimilation of the resource flow.
Decisions
As we watch a fresh start on a blank slate (with tiny beads of water beginning to accumulate), the path of the upstart is only predictable in the widest sense: it will flow sort-of downhill. Life is similarly predictable in broad-brush: flowing from birth to death, accumulating resources, reproducing: all the things it must do to remain a part of Life. But rivulets on windshields express jigs and jags; pauses and sprints. Likewise, (most forms of) lightning will predictably reach from cloud to ground, but by creative, jagged paths—consisting of many branch points (decisions).
As the rivulet forms, it sometimes takes unexpected turns by happening to glance a droplet, encounter a defect on the substrate, or perhaps get nudged by an incoming rain drop or gust of wind. It’s got some randomness to it: not strictly predictable. What makes it decide to go left or right—or to pause or race—can’t be foreseen by us, even if we can work backwards and make sense of the influences that played a role in shaping its particular behavior.
Like fire, lightning, or a leaf in the wind, the rivulet can appear to have a mind of its own, executing “interesting” behaviors.
Feedback
Here’s where the rubber meets the road. A rivulet that has made “good” decisions…so that it:
- is effective at clearing a region of the windshield;
- “plays well” with the other rivulets in place;
- and leaves a path that encourages future generations to follow…
will be the rivulet that persists. Rivulets that make “poor” decisions will fail to establish any sort of permanence, for any number of retrospectively-obvious reasons. Evolutionary feedback operates on what initially might be random decisions, but patterns of decisions become selected based on their demonstrated ability to contribute to success.
That an amoeba appears to execute sensible reactions to a food gradient—navigating itself to a meal—is a similar selection effect. The degree of complexity compared to a rivulet is already stupendous in this case, but not obviously operating on an entirely different plane. What would be truly remarkable is an amoeba that systematically fled food, ran toward danger, and refused to reproduce. Such decision patterns obviously perish from Earth. One may imagine (even if actually cognitively incapable of the feat) elaborating from the rivulet to the amoeba and then toward more complex organisms, following the same principles. That the squirrel dithers in the road in reaction to an oncoming car points to competing processes in an exceedingly complex decision-tree juggling a swarm of stimuli all at once.
An Ecology
One rivulet does not clear the entire windshield efficiently. There’s only so much it can do. Others necessarily crop up and interact. Some interfere, and others reinforce. One can imagine a late-stage equilibrium of sorts where the self-preserving (replicating) rivulets are as a whole clearing the rainfall in a mature, stable pattern. These are the results of an evolutionary process, sensitive to the many random-but-effective—and interacting—decisions that contributed to each rivulet’s path. In hindsight, they look like genius decisions—simultaneously weighing many factors and relationships. But, that’s just what worked, in the full context. Surviving decisions have to be good ones by this measure.
Evolution
Real ecologies are always on the move as continents shift, climate changes, volcanoes erupt, Life evolves/migrates, and any number of other disturbances manifest. To better approximate the real deal, we’re going to need a bigger windshield! The rain rate won’t be the same everywhere, and can also slowly vary.
Rivulets well-adapted to a particular static condition will begin to fail in the same configuration under changed conditions. But if the changes are slow enough, some rivulets will be able to adapt by their own random set of “good” decisions (mutations), while others will perish and be replaced by new structures that may compete for a while before establishing something new that works in relation to the rest.
And, of course, our windshield is a much simpler “parameter space” than a real, complex ecosystem. Instead of rainfall rate, slope, and surface properties, we have a rich set of interacting ingredients relevant to how Life forms and maintains itself.
Also important is timescale. Life had billions of years to establish. Even though waiting in the car for my mom might have seemed like a billion years, my attention span was likely insufficient to witness the establishment of a mature state (and variable rainfall conditions probably precluded such an emergence anyway).
Taking Stock
The rivulet analogy, like any, will be imperfect. But it does illustrate the principle of how inanimate systems possessing some self-replication capability under a metric of success in feedback can utilize standard physics and randomness to try configurations and persist when hitting on the right, lucky mix of decisions. Just give it time.
Few upstarts will have what it takes to satisfactorily match the resource provision and work in concert with the others, thus will be forgotten. Likewise, any lifeform that can’t incorporate the physics at hand to achieve a “golden” state simply won’t hang around to be admired.
We have in the rivulets, then, self-replicating structures that appear to make decisions, operating under an evolutionary pressure so that survivors are the ones who made “correct” decisions in relation to the other happenings around it—and continue to execute those genius decisions by dint of the blueprints in place. The entire windshield shapes each mature rivulet via many interdependencies and resource-matching conditions in a pass/fail feedback arrangement. Evolution is also possible, as the ecology of rivulets adjusts to slow changes.
The Hard Part
Even a meat-brain like mine can guide the assembly of atoms (designing and building technological devices) in ways that perform sensing and decision-making. But nothing I ever built came anywhere close to being able to self-replicate, secure necessary resources and fashion them into the desired configurations, operating within an interactive ecology of similar creations. Sensing and deciding are actually the easy parts, and are quickly shaped by selective criteria once the barrier of a self-replicating capability is achieved. Having secured this feat, natural variations and selective pressure can generate all manner of impressive (progressively more elaborate) decision-making processes that bear on survival. Feedback makes it look magical.
Note also that unlike real Life, rivulets starting from scratch are far more likely to fail in establishing permanence, having no benefit of evolutionary heritage in having an instinct for the right decisions. Conversely, each species in the Community of Life inherited a successful set of vetted decisions, and thus starts from a position of (proven) success, not (presumed) failure.
The Vast Gulf
I am not claiming that we need to consider rivulets or fire or lightning as animate forms of Life. The difference in complexity is truly staggering. Yet, the comparison offers a mottled window—especially into decision-making processes that appear (via feedback/success) to be directed, or purposeful. Their self-defining or reinforcing purpose is to promote continuation, in aggregate.
When we witness a family of adult quail with lots of babies (fuzzy walnuts) zipping into the bushes in reaction to an overhead hawk, we call that a good decision. So does evolution. If the quail’s “internal rivulets” were not formed in such a way as to produce suitable reactions, then we would not enjoy their company today. What looks like magic in the form of a proactive decision is in some sense the only way things can go. Or, at least, it’s a way that has been proven to work well enough in a complex and variable context, and that’s all it takes.
Does this perspective make Life any less amazing, magnificent, splendid, extraordinary? It needn’t. One might even say that this viewpoint makes Life all the more remarkable—for being able to craft a viable living out of the basic physics at hand. Human brains are woefully incapable of conjuring—or even fully grasping—any such amazingness.
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If you’ll forgive me one very last spruik of “Free Agents” by Kevin Mitchell. For those interested and that perhaps might need further convincing, it fleshes out the main message that (I take it is) that you are communicating here, Tom. This provides an amazing survey and analysis of the emergence of organisms that increasingly “appear” as “free” agents thanks to increasing internal material complexity, tied to increasingly complex multi-input feedback loops, leading us modern day humans to make the mistake of thinking that “life” (and especially us) is somehow fundamentally different to everything else in the cosmos/universe (this last bit is at least my take on what is outlined in the bulk of the book). The evolutionary perspective is so vital to “understanding it all”.
The summary and first five minutes of audio (all that is available to me) appears to come to the opposite conclusion: rejecting illusionism, determinism, and embracing free will (like most people). Maybe these are misleading representations.
I'm saying that living beings execute a script of pure physics, written in real time (with probabilistic twists), but guided/constrained by patterns that have been selected to work in an evolutionary and ecological sense.
We can't tell the difference between physics-scripted and "free" (when constrained to the physically plausible). Consider that actors following a (physics-compliant) script are convincing to us. If sat in a waiting room and watched an interaction between two people, we would not be able to say if it was scripted by physics or by a director intent on fooling us. Now imagine an animation. Random pixel patterns will not be "realistic," nor would morphologically bizarre or shape-shifting or physics-defying "characters." But hew to the patterns and behaviors that physics and evolution support, and we have ourselves a believable story. We are unable to differentiate, importantly. Compared to the staggeringly-large set of possible pixel patterns, a tiny tiny tiny subset will pass muster: virtually all of the "freedom" is removed. Life is not dissimilar.
Thanks Tom.
I should have made it clear that I don’t think that the overall interpretations of you and the author are similar (they are clearly not). However, the bulk of the book (after the first chapter) presents a fascinating evolutionary/historical account of how organisms that appear increasingly “independent” or under internal control have emerged thanks to growing complexity in the physical arrangements of matter present in (some) new life forms, with this complexity intimately linked to an increase in the complexity of the feedback/regulatory mechanisms at play. It is this aspect of the book that I think does add “meat to the bones” of what you are saying in your post: it so critical to appreciate the role of feedback and just how complex the arrangements of physical matter underpinning the phenomenon of “life” truly are. I think this side of the book will be of interest to many people regardless of their preferred overall interpretation of “what it all precisely means”, particularly with regards to ideas like free will, etc. The author is a neuroscientist that is clearly all over the latest data.
I also baulked at things said by him in the first chapter, which perhaps might have been better left till the end to prevent people having a premature allergic reaction. These reflect his overall interpretation. I found it very useful to press on because the book provided me with a new found appreciation of just how complex the molecular goings-on of life truly are. More complex than I can fathom! The stuff about gene regulation in multi-cellular organisms, for example, was fascinating.
A useful clarification—thanks! Indeed, your initial summary sounded right up my alley, leading me to think the book was promoting the illusory *appearance* of free will, etc. out of increasingly complex evolutionary arrangements. I then got confused reading a summary of the book and its take-away. But I'm perfectly capable of absorbing the factual parts while ignoring mythological spin. And yes, the complexity is too big for our brains: another reason to refrain from claiming that we know better than the premise that a material basis is all that's needed. Plenty of room outside our vapid brains for that to manifest…
Einstein: "One can best feel in dealing with living things how primitive physics still is."
Self-organisation occurs in inorganic matter, but self-*replication* does not. Still no one has a clue about how the animate came from the inanimate in the first place, a "feat" you skip over in an effort to squeeze life into the materialist box – but it just won't fit.
"just won't fit" …in our brains (which never should be the criterion).
I think there's enough content to allow a window into how inanimate becomes animate: once a molecule (or set thereof) hits on self-replication, selective influences promote/demote behaviors until the critter follows food gradients and the like. Only the ones that do develop such "purposeful" responses to stimuli remain animate. It wouldn't work otherwise.
Science 'explains' what goes on only *once the self-replication has happened*. But how did it happen?
Life depends on systems that copy DNA and translate it into proteins. For evolution to begin, a minimum level of transcription accuracy is required.
In order to attain the complexity needed for an organism to achieve this transcription accuracy, a system of even greater complexity (ie, one for encoding error correction enzymes) is needed.
The probablity of a coupled translation-replication emerging by chance is less than 1 in 10^1018.
Plenty of plausible speculation has gone into the most primitive self-replication capability at the molecular level (which is FAR simpler than the evolved DNA/RNA methods that evolved and stuck around). I'm not saying it's easy. Our brains are not as talented as a planet's-worth of molecules given hundreds of millions of years to bump around in favorable conditions. This is where a smidge of right-brain allowance is useful: we needn't insist on tracking the specifics with the left brain to admit that it's possible (and appears to have actually happened). Once the most primitive self-replication is present, selection marches in.
But if we've managed to move the ball to this point (so that behaviors/decisions/purpose are evolved arrangements much like beaks or feet), then that's pretty huge.
But it's the *left brain* that insists on the reductionist model (and models generally). It literally reduces the world to the smallest parts it can conceive of, and then reconstructs it from its lego (atoms). The right brain has no need of it.
I never had a problem with evolution, only with reductionism.
The items in the last sentence are not arrangements. To an extent, behaviour is evolved. Decisions/purpose cannot be said to have evolved. Beings evolved, with the ability to make decisions, for whatever suits their purposes.
The origin of self-replication seems like a problem for the reductionists. They seem to say 'we don't know the details, but – atoms'. Of course life is made of atoms, and of course they are in complex arrangements. That does not come close to accounting for its intrinsic purposiveness.
Even with bags of time and molecules etc. the odds are still massively against so-called 'abiogenesis'.
I poke at the left brain thing with you because it's a bit of pot and kettle calling each other black. Your reductive characterization of the situation is classic! It borders on hilarious. Check your statements (here and elsewhere) for certainty, definitiveness, categorical logic, etc.: plenty to find.
Any argument that has any hint of logic involves substantial (or even dominant) left-brain engagement—more so when expressed in words. I learned a ton from McGilchrist's Master/Emissary book, and was highly amused by his follow-up (Matter with Things) that dove deep on a mental model for how the universe works in a way that can satisfy the certainty cravings of the left hemisphere. Right hemispheres have essentially no opinions: virtually any argument is tolerated/entertained—even mutually exclusive ones (on logical grounds). It's pointless to pretend that our expressed views are free of the influence of either hemisphere, and indeed a comment forum is bound to be primarily a left-hemisphere playground.
One point I frequently stress without effect is that my position has a huge element of surrender to it. It's a slap to the left brain. I don't insist that we gain certainty on tracking the tangled complexity, the way a left-brain demands. Then your objection is that it's not all tracked down ("atoms"). That feels to me like differing levels of comfort with ambiguity and unknowing, which I embrace, here.
My main position is that we have zero standing to assert that it takes more than material (atoms in arrangement) to produce all our experience—even if we can't placate the left brain that we can pin down just how. My main allergy is to dualism: categorically separating animate/inanimate, mind/body, subject/object. Those are the sharp tools of the left, and I suspect that reality is far mushier: a oneness that can take on a diverse set of superficial attributes without being ontologically separate (our left projection is where this desire arises). In the mind/matter debate, I side strongly with matter/matter over mind/mind: our experience of mind is a manifestation of matter and not the puzzling reverse. I am uneasy with the impulse to create artificial divisions, and seek a holistic single picture that unites us with the entire universe in a tangled mess—one that will almost certainly defy our insistence on nailing down every detail. It's enough for me to seek plausibility arguments, as my posts tend to pursue. It's a "there, there" soothing of the twitchy left hemisphere: who am I to say it can't be all one mess of matter; let it be; what's to fear…
You're hilarious too. You protest about humilty, surrender and so on – then say, with certainty, 'animals are mechanisms', in a way that would make Descartes proud.
The purpose of a mechanism is whatever it was designed to do. No one designed Life – so where does its purpose originate?
I'm not objecting that the atomic arrangements aren't all tracked down. All I'm saying is that the intrinsic purposiveness of life is not attributable to a mechanism. I have no idea of the 'answer' (no certainty here).
Certainty: 'it *must* be all matter' (whatever matter is). I genuinely don't know. If you *do* know, that must be great – probably how all True Believers feel…
What the actual Descartes would love is your keeping his flames of dualism alive by insisting that something other than matter is required. He would vociferously object to lumping souls in as a mechanism of matter.
You claim that mechanisms require design and purpose. By what authority? That's a bizarre, artificially-imposed condition the universe is free to ignore.
For the how-many-th time (always lost): my position is strong *advocacy* for a unified foundation, not proclamation. I express a strong preference for a non-dualistic oneness, without invoking/positing/asserting that something else must be involved, or that an unbridgeable divide separates animate from inanimate. I advocate complaisance: matter is good enough until proven otherwise, even if our brains aren't up to specifying all the steps (which you castigate as: 'but…atoms"…so you *do* object, in deed). Who are we to assert otherwise? Go with what the universe presents, not what our brains conjure out of the ether. It presents matter and interactions everywhere we ever look (even in living beings!!), and I say: message received.
Your "not attributable to a mechanism" is exactly what the certainty of a true believer looks like, by the way. It's a certainty you can't possibly back up (nor can any meat-brain). Faced with uncertainty, I simply acquiesce to the simplest non-dualistic stance of: all one origin (based on the interactions presented to us), expressing in a diversity of ways, without needing to conjure extra layers to paper-over ignorance. Let us sit with that ignorance and be satisfied. Let the left squirm.
I express a strong preference for a non-dualistic oneness, but also suspect that something else must be involved, and that a divide separates animate from inanimate.
What is that 'something else'? That's where I say (again) I don't know. Why 'something else'? Because, where did the universe or matter come from? I don't know that, either.
Your "it must be a mechanism" is exactly what the certainty of a true believer looks like. It's a certainty you can't possibly back up. Nor can any living brain (meat is *dead* flesh – there's a difference between living and dead, as well as animate and inanimate).
Anyway, thanks for taking the time to discuss these things. We may not agree, but that doesn't matter, does it?
If you're going to "quote" me and then use the quote to misrepresent my stance, ideally it would be something I actually said. A more accurate capture is: we have no basis on which to assert that it can't be mechanistic, so I strongly prefer a non-dualist matter-only approach. I'm not in the business of proclaiming, just supporting monism and challenging artificial divides produced by brains too feeble to smoke the full connection (mine included, to be clear). False equivalencies do little to advance the conversation.
You say that "Every living being comes from beings able to reproduce/replicate." But this wasn't always true, or life would never have gotten started. Would it?
I didn't feel the need to encumber the sentence with extra words like "alive today" or "that you have ever laid eyes on" because it's been essentially true for 4 billion years.
Tom,
Nice post. I was in the 7’th grade when my biology teacher asked us the same question, “what is life”?” We gave various answers and then he gave the same one you did, that life can reproduce.
One thing I’ve been thinking about is Musk’s obsession with Mars as a life raft for humanity. Given how fine tuned evolution is, I think it’s highly unlikely that humans would be able to reproduce over generations living in the 3.7 m/s2 gravity of Mars when life evolved under 9.8 m/s2 acceleration here on earth.