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Why Life Does Not Really Exist

The views expressed are those of the author and are not necessarily those of Scientific American.

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native bee

A native bee in my backyard (Credit: Ferris Jabr)

I have been fascinated with living things since childhood. Growing up in northern California, I spent a lot of time playing outdoors among plants and animals. Some of my friends and I would sneak up on bees as they pollinated flowers and trap them in Ziploc bags so we could get a close look at their obsidian eyes and golden hairs before returning the insects to their daily routines. Sometimes I would make crude bows and arrows from bushes in my backyard, using stripped bark for string and leaves for fletchings. On family trips to the beach I learned how to quickly dig crustaceans and arthropods out of their hiding spots by watching for bubbles in the sand as the most recent wave retreated. And I vividly recall an elementary school field trip to a grove of eucalyptus trees in Santa Cruz, where thousands of migrating monarch butterflies had stopped to rest. They clung to branches in great brown globs, resembling dead leaves—until one stirred and revealed the fiery orange inside of its wings.

Moments like that—along with a number of David Attenborough television specials—intensified my enthrallment with the planet’s creatures. Whereas my younger brother was obsessed with his K’Nex set—meticulously building elaborate roller coasters—I wanted to understand how our cat, well, worked. How did she see the world? Why did she purr? What were fur and claws and whiskers made of? One Christmas I asked for an encyclopedia of animals. After ripping the wrapping paper off a massive book that probably weighed half as much as I did, I sat near the tree reading for hours. Not too surprising, then, that I ended up writing about nature and science for a living.

A K'Nex contraption (Credit: Druyts.t via Wikimedia Commons)

Recently, however, I had an epiphany that has forced me to rethink why I love living things so much and reexamine what life is, really. For as long as people have studied life they have struggled to define it. Even today, scientists have no satisfactory or universally accepted definition of life. While pondering this problem, I remembered my brother’s devotion to K’Nex roller coasters and my curiosity about the family cat. Why do we think of the former as inanimate and the latter as alive? In the end, aren’t they both machines? Granted, a cat is an incredibly complex machine capable of amazing behaviors that a K’Nex set could probably never mimic. But on the most fundamental level, what is the difference between an inanimate machine and a living one? Do people, cats, plants and other creatures belong in one category and K’Nex, computers, stars and rocks in another? My conclusion: No. In fact, I decided, life does not actually exist.

Allow me to elaborate.

Formal attempts to precisely define life date to at least the time of ancient Greek philosophers. Aristotle believed that, unlike the inanimate, all living things have one of three kinds of souls: vegetative souls, animal souls and rational souls, the last of which belonged exclusively to humans. Greek anatomist Galen proposed a similar, organ-based system of “vital spirits” in the lungs, blood and nervous system. In the 17th century, German chemist George Erns Stahl and other researchers began to describe a doctrine that would eventually become known as vitalism. Vitalists maintained that “living organisms are fundamentally different from non-living entities because they contain some non-physical element or are governed by different principles than are inanimate things” and that organic matter (molecules that contained carbon and hydrogen and were produced by living things) could not arise from inorganic matter (molecules lacking carbon that resulted primarily from geological processes). Subsequent experiments revealed vitalism to be completely untrue—the inorganic can be converted into the organic both inside and outside the lab.

Instead of imbuing organisms with “some non-physical element,” other scientists attempted to identify a specific set of physical properties that differentiated the living from the nonliving. Today, in lieu of a succinct definition of life, Campbell and many other widely used biology textbooks include a rather bloated list of such distinguishing characteristics, for instance: order (the fact that many organisms are made from either a single cell with different compartments and organelles or highly structured groups of cells); growth and development (changing size and shape in a predictable manner); homeostasis (maintaining an internal environment that differs from an external one, such as the way cells regulate their pH levels and salt concentrations); metabolism (expending energy to grow and to delay decay); reacting to stimuli (changing behavior in response to light, temperature, chemicals or other aspects of the environment); reproduction (cloning or mating to produce new organisms and transfer genetic information from one generation to the next); and evolution (the change in the genetic makeup of a population over time).


A tardigrade can survive without food or water in a dehyrated state for more than 10 years (Credit: Goldtsein lab via Wikimedia Commons via Flickr)

It’s almost too easy to shred the logic of such lists. No one has ever managed to compile a set of physical properties that unites all living things and excludes everything we label inanimate. There are always exceptions. Most people do not consider crystals to be alive, for example, yet they are highly organized and they grow. Fire, too, consumes energy and gets bigger. In contrast, bacteria, tardigrades and even some crustaceans can enter long periods of dormancy during which they are not growing, metabolizing or changing at all, yet are not technically dead. How do we categorize a single leaf that has fallen from a tree? Most people would agree that, when attached to a tree, a leaf is alive: its many cells work tirelessly to turn sunlight, carbon dioxide and water into food, among other duties. When a leaf detaches from a tree, its cells do not instantly cease their activities. Does it die on the way to the ground; or when it hits the ground; or when all its individual cells finally expire? If you pluck a leaf from a plant and keep its cells nourished and happy inside a lab, is that life?

Such dilemmas plague just about every proposed feature of life. Responding to the environment is not a talent limited to living organisms—we have designed countless machines that do just that. Even reproduction does not define a living thing. Many an individual animal cannot reproduce on its own. So are two cats alive because they can create new cats together, but a single cat is not alive because it cannot propagate its genes by itself? Consider, also, the unusual case of turritopsis nutricula, the immortal jellyfish, which can indefinitely alternate between its adult form and its juvenile stage. A jelly vacillating in this way is not producing offspring, cloning itself or even aging in the typical fashion—yet most people would concede it remains alive.

But what about evolution? The ability to store information in molecules like DNA and RNA, to pass on this information to one’s offspring and to adapt to a changing environment by altering genetic information—surely these talents are unique to living things. Many biologists have focused on evolution as life’s key distinguishing feature. In the early 1990s, Gerald Joyce of the Scripps Research Institute was a member of an advisory panel to John Rummel, manager of NASA’s exobiology program at the time. During discussions about how best to find life on other worlds, Joyce and his fellow panelists came up with a widely cited working definition of life: a self-sustaining system capable of Darwinian evolution. It’s lucid, concise and comprehensive. But does it work?

Let’s examine how this definition handles viruses, which have complicated the quest to define life more than any other entity. Viruses are essentially strands of DNA or RNA packaged inside a protein shell; they do not have cells or a metabolism, but they do have genes and they can evolve. Joyce explains, however, that in order to be a “self-sustaining system,” an organism must contain all the information necessary to reproduce and to undergo Darwinian evolution. Because of this constraint, he argues that viruses do not satisfy the working definition. After all, a virus must invade and hijack a cell in order to make copies of itself. “The viral genome only evolves in the context of the host cell,” Joyce said in a recent interview.

A cluster of bacteriophages, viruses that evolved to infect bacteria (Credit: Dr Graham Beards via Wikimedia Commons)

When you really think about it, though, NASA’s working definition of life is not able to accommodate the ambiguity of viruses better than any other proposed definition. A parasitic worm living inside a person’s intestines—widely regarded as a detestable but very real form of life—has all the genetic information it needs to reproduce, but it would never be able to do so without cells and molecules in the human gut from which it steals the energy it needs to survive. Likewise, a virus has all the genetic information required to replicate itself, but does not have all the requisite cellular machinery. Claiming that the worm’s situation is categorically different from that of the virus is a tenuous argument. Both the worm and virus reproduce and evolve only “in the context” of their hosts. In fact, the virus is a much more efficient reproducer than the worm. Whereas the virus gets right down to business and needs only a few proteins inside a cell’s nucleus to initiate replication on a massive scale, the parasitic worm’s reproduction requires use of an entire organ in another animal and will be successful only if the worm survives long enough to feed, grow and lay eggs. So if we use NASA’s working definition to banish viruses from the realm of life, we must further exclude all manner of much larger parasites including worms, fungi and plants.

Defining life as a self-sustaining system capable of Darwinian evolution also forces us to admit that certain computer programs are alive. Genetic algorithms, for instance, imitate natural selection to arrive at the optimal solution to a problem: they are bit arrays that code traits, evolve, compete with one another to reproduce and even exchange information. Similarly, software platforms like Avida create “digital organisms” that “are made up of digital bits that can mutate in much the same way DNA mutates.” In other words they, too, evolve. “Avida is not a simulation of evolution; it is an instance of it,” Robert Pennock of Michigan State University told Carl Zimmer in Discover. “All the core parts of the Darwinian process are there. These things replicate, they mutate, they are competing with one another. The very process of natural selection is happening there. If that’s central to the definition of life, then these things count.”

I would argue that Joyce’s own lab delivered another devastating blow to NASA’s working definition of life. He and many other scientists favor an origin of life story known as the RNA world hypothesis. All life on our planet depends on DNA and RNA. In modern living organisms, DNA stores the information necessary to build the proteins and molecular machines that together form a bustling cell. At first, scientists thought only proteins known as enzymes could catalyze the chemical reactions necessary to construct this cellular machinery. In the 1980s, however, Thomas Cech and Sidney Altman discovered that, in collaboration with various protein enzymes, many different kinds of RNA enzymes—or ribozymes—read the information coded in DNA and build the different parts of a cell piece by piece. The RNA world hypothesis posits that the earliest organisms on the planet relied solely on RNA to perform all these tasks—to both store and use genetic information—without the help of DNA or an entourage of protein enzymes.

geothermal pool

A geothermal pool in Wyoming. Nearly four billion years ago, what we call life may have first evolved in similar "warm little ponds," as Darwin put it. (Credit: Caleb Dorfman, via Flickr)

Here’s how it might have happened: Nearly four billion years ago, in Earth’s primordial soup, free-floating nucleotides—the building blocks of RNA and DNA—linked into longer and longer chains, eventually producing ribozymes that were big enough and complex enough to make new copies of themselves and thus had a much greater chance of surviving than RNAs that could not reproduce. Simple self-assembling membranes enveloped these early ribozymes, forming the first cells. In addition to making more RNA, ribozymes may have joined nucleotides into chains of DNA; nucleotides may have spontaneously formed DNA as well. Either way, DNA replaced RNA as the main information-storing molecule because it was more stable. And proteins took on many catalytic roles because they were so versatile and diverse. But the cells of modern organisms still contain what are likely remnants of the original RNA world. The ribosome, for example—a bundle of RNA and proteins that builds proteins one amino acid at a time—is a ribozyme. There’s also a group of viruses that use RNA as their primary genetic material

To test the RNA world hypothesis, Joyce and other researchers have tried to create the types of self-replicating ribozymes that may have once existed in the planet’s primordial soup. In the mid-2000s, Joyce and Tracey Lincoln constructed trillions of random free-floating RNA sequences in the lab, similar to the early RNAs that may have competed with one another billions of years ago, and isolated sequences that, by chance, were capable of bonding two other pieces of RNA. By pitting these sequences against one another, the pair eventually produced two ribozymes that could replicate one another ad infinitum as long as they were supplied with sufficient nucleotides. Not only can these naked RNA molecules reproduce, they can also mutate and evolve. The ribozymes have altered small segments of their genetic code to adapt to fluctuating environmental conditions, for example.

“They meet the working definition of life,” Joyce says. “It’s self-sustaining Darwinian evolution.” But he hesitates to say that the ribozymes are truly alive. Before he goes all Dr. Frankenstein, he wants to see his creation innovate a completely new behavior, not just modify something it can already do. “I think what’s missing is that it needs to be inventive, needs to come up with new solutions,” he says.

But I don’t think Joyce is giving the ribozymes enough credit. Evolution is a change in genes over time; one does not need to witness pigs sprouting wings or RNAs assembling into the letters of the alphabet to see evolution at work. The advent of blue eye color between 6,000 and 10,000 years ago—simply another variation of iris pigments—is just as legitimate an example of evolution as the first feathered dinosaurs. If we define life as a “self-sustaining system capable of Darwinian evolution,” I cannot see any legitimate reason to deny self-replicating ribozymes or viruses the moniker of life. But I do see a reason to ditch this working definition and all other definitions of life altogether.

Why is defining life so frustratingly difficult? Why have scientists and philosophers failed for centuries to find a specific physical property or set of properties that clearly separates the living from the inanimate? Because such a property does not exist. Life is a concept that we invented. On the most fundamental level, all matter that exists is an arrangement of atoms and their constituent particles. These arrangements fall onto an immense spectrum of complexity, from a single hydrogen atom to something as intricate as a brain. In trying to define life, we have drawn a line at an arbitrary level of complexity and declared that everything above that border is alive and everything below it is not. In truth, this division does not exist outside the mind. There is no threshold at which a collection of atoms suddenly becomes alive, no categorical distinction between the living and inanimate, no Frankensteinian spark. We have failed to define life because there was never anything to define in the first place.

I nervously explained these ideas to Joyce on the phone, anticipating that he would laugh and tell me they were absurd. After all, this is someone who helped NASA define life. But Joyce said the argument that life is a concept is “perfect.” He agrees that the mission to define life is, in some ways, futile. The working definition was really just a linguistic convenience. “We were trying to help NASA find extraterrestrial life,” he says. “We couldn’t use the word ‘life’ in every paragraph and not define it.”

Carol Cleland, a philosopher at the University of Colorado Boulder who has spent years researching attempts to deliniate life, also thinks that the instinct to precisely define life is misguided—but she is not yet ready to deny life’s physical reality. “It’s just as premature to reach the conclusion that there is no intrinsic nature to life as it is to define life,” she says. “I think the best attitude is to treat what are normally taken as the definitive criteria of life as tentative criteria.”

A photo taken with an electron scanning microscope of the ALH 84001 meteorite, which supposedly formed on Mars 4 billion years ago before eventually reaching Earth. A handful of scientists think the chain-like structures in the photo are fossilized Martian nanobacteria, but most researchers are skeptical (Credit: NASA, via Wikimedia Commons)

What we really need, Cleland has written, is “a well-confirmed, adequately general theory of life.” She draws an analogy to chemists in the sixteenth century. Before scientists understood that air, dirt, acids and all chemical substances were made of molecules, they struggled to define water. They could list its properties—it was wet, transparent, tasteless, freezable and it could dissolve many other substances—but they could not precisely characterize it until researchers discovered that water is two hydrogen atoms bonded to an oxygen atom. Whether salty, muddy, dyed, liquid or frozen, water is always H20; it may have other elements mixed in, but the tripartite molecules that make what we call water water are always there. Nitric acid may resemble water, but it is not water because the two substances have different molecular structures. Creating the equivalent of molecular theory for life, Cleland says, will require a larger sample size. She argues that, so far, we have only one example of what life is—the DNA and RNA-based life on Earth. Imagine trying to create a theory about mammals by observing only zebras. That’s the situation we find ourselves in when trying to identify what makes life life, Cleland concludes.

I disagree. Discovering examples of alien life on other planets would undoubtedly expand our understanding of how the things we call living organisms work and how they evolved in the first place, but such discoveries would probably not help us formulate a revolutionary new theory of life. Sixteenth century chemists could not pinpoint what distinguished water from other substances because they did not understand its fundamental nature: they did not know that every substance was made of a specific arrangement of molecules. In contrast, modern scientists know exactly what the creatures on our planet are made of—cells, proteins, DNA and RNA. What differentiates molecules of water, rocks, and silverware from cats, people and other living things is not “life,” but complexity. Scientists already have sufficient knowledge to explain why what we have dubbed organisms can in general do things that most of what we call inanimate cannot—to explain how bacteria make new copies of themselves and quickly adapt to their environment, and why rocks do not—without proclaiming that life is this and non-life that and never the twain shall meet.

Recognizing life as a concept in no way robs what we call life of its splendor. It’s not that there’s no material difference between living things and the inanimate; rather, we will never find some clean dividing line between the two because the notion of life and non-life as distinct categories is just that—a notion, not a reality. Everything about living creatures that fascinated me as a boy are equally wondrous to me now, even with my new understanding of life. I think what truly unites the things we say are alive is not any property intrinsic to those things themselves; rather, it is our perception of them, our love of them and—frankly—our hubris and narcissism.

First, we announced that everything on Earth could be separated into two groups—the animate and inanimate—and it is no secret which one we think is superior. Then, not only did we place ourselves in the first group, we further insisted on measuring all other life forms on the planet against ourselves. The more similar something is to us—the more it appears to move, talk, feel, think—the more alive it is to us, even though the particular set of attributes that makes a human a human is clearly not the only way (or, in evolutionary terms, even the most successful way) to go about being a ‘living thing.’


Our late family cat, Jasmine (Credit: Jabr family)

Truthfully, that which we call life is impossible without and inseparable from what we regard as inanimate. If we could somehow see the underlying reality of our planet—to comprehend its structure on every scale simultaneously, from the microscopic to the macroscopic—we would see the world in innumerable grains of sand, a giant quivering sphere of atoms. Just as one can mold thousands of practically identical grains of sand on a beach into castles, mermaids or whatever one can imagine, the innumerable atoms that make up everything on the planet continually congregate and disassemble themselves, creating a ceaselessly shifting kaleidoscope of matter. Some of those flocks of particles would be what we have named mountains, oceans and clouds; others trees, fish and birds. Some would be relatively inert; others would be changing at inconceivable speed in bafflingly complex ways. Some would be roller coasters and others cats.

About the Author: Ferris Jabr is an associate editor focusing on neuroscience and psychology. Follow on Twitter @ferrisjabr.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. Fine Material 11:01 am 12/2/2013

    Very good article, thanks.

    I’ve always thought along these lines. It is news to me that people are still open to the possibility of “Frankenstein Magic” (for want of a better word). The chemical reactions of life are understood better every year, and no one is proposing to add magic to the list of needed reactions.

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  2. 2. Cognosium 3:34 pm 12/2/2013

    Well said, Ferris. An objective appraisal of the understandings of the world that are today available to us inevitably leads to the conclusion that there can be no fundamental distinction between biology and other chemistries and physical processes.

    There are, of course, useful practical distinctions to be made but these are somewhat arbitrary.

    It is interesting, however, to extend the concept of “life” to include the evolutionary processes that occur, for example, in stellar nucleosynthesis, geology and, most visibly, the evolution of technology within the collective imagination of our species. The latter having a selection mechanism very much akin to that of biology.

    This wider perspective implies a life process that identifies with the concept of an evolutionary continuum.

    This is expanded upon in “The Goldilocks Effect: What Has Serendipity Ever Done For Us?” which is a free download in e-book formats from my “Unusual Perspectives” website. It is a very informal treatment but sufficient to give the gist.

    I am currently preparing a much more formal exposition “The Intricacy Generator: Pushing Chemistry Uphill”.
    Work on this has been held up by major health issues but I hope to have it completed early next year.

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  3. 3. Gord Davison 4:48 pm 12/2/2013

    It is interesting how many people consider that life is to those that have ‘souls’ but yet have never defined what a soul is nor have they ever identified or even hypothesized what material the soul may be made of. Some religions tell us that only the human animal has a soul therefor differentiating humans from all of the other animals. I find this quit arrogant and stupid. I think the concept of a soul can be replaced by the concept of consciousness and self awareness.

    The idea of varying degrees of consciousness seems to be part of the definition of life. Different living things have different abilities to affect their environment and to observe it so they can respond to changes. Trees sens the sun and can face the sun as well as loose their leaves as the daylight shortens, toads croak out mating calls in the middle of the night. These are all things that conscious living things do as they are affected by their environment and attempt to affect it.

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  4. 4. alphan 5:48 pm 12/2/2013

    Not so fast…
    Well of course we would not be able to find anything beyond the determined when you are taking minor snapshots of processes that took billions of years to evolve. Physics and Chemistry without biology and the concept of life are like a “false” Laplace’s Daemon; looking from a certain point, in a given environment, you can always assume that you can tell what the end result is. It is like what the GMO defenders are suggesting with regards to selective breeding that we have been genetically modifying species all through human history, what could possibly be different if we did the same kind of modification in the laboratory? However the environment that selective breeding is done in, the Earth, with immense variables, sets the unseen and unaccounted for physical and biological boundaries as a given. The comprehension of what life is and what it can sustain is not only infinitely perfectible it is also ever changing. You say ” If we could somehow see the underlying reality of our planet—to comprehend its structure on every scale simultaneously, from the microscopic to the macroscopic—we would see the world in innumerable grains of sand, a giant quivering sphere of atoms.” and I say there is a life based meaningful way of comprehending all of it. I would like to direct you to two links, the first one is about the inability of the current science to place thinking in the body, the second about the meaning of life. And now for something completely different!

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  5. 5. Devonshire 5:53 pm 12/2/2013

    “I think computer viruses should count as life. I think it says something about human nature that the only form of life we have created so far is purely destructive. We’ve created life in our own image.”

    The brilliant Professor, Astrophysicist, Cosmologist, Stephen Hawking

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  6. 6. anguebus 6:04 pm 12/2/2013

    Thanks for the article.

    To say that life and living beings are “complex systems” may be more a starting point than an endpoint on one of the most debated issues in the history of thought and formal and experimental sciences (what really life is?). To put it better, I should say that the concept of “complex systems” is just one of the necessary intermediate stations on the long journey in search of consistent answers on that question.

    I think that the more elaborate responses on this issue still are the provided by the information theory, and that the best coordinates on which analyze the question are those provided by the laws of thermodynamics.

    Already Lucretius in Book IV of his “De Rerum Natura” (1st-century BC ), in developing his “theory of simulacra” pointed to -according to many of his modern interpreters- the importance of information and the ability to self-organization in determining what is and what is not animated nature (living things).

    There are many complex systems in nature, such many as measurement scales we use. But not one of the known omplex systems, except living beings, is able of recover as useful information the energy that he uses and dissipates. That would be the big difference: the ability to recover as information the energy who have been previously consumed. So, as a local exception to the second law of thermodynamics, living beings are able to overcome the mandate to generate entropy, and they can create new structure, self-organize and expand in space and time (reproduction), by its ability to generate new information (encoding nucleic acids) from the energy they have first captured from abroad and used in their internal metabolism.

    Just as Lucretius said he sought to reveal what they had already set before him Democritus or Epicurus, I just wanted to point out now the perspective that have made on this matter physicists and ecologists like Ilya Prigogyne or Ramón Margalef.

    Salvador Robles (anguebus)

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  7. 7. RSchmidt 6:48 pm 12/2/2013

    I once thought that life was a state of being. Things were either animate or inanimate. But that didn’t seem to fit so I began to think of life as a process, metabolism, growth, respiration but that didn’t seem to cover it. Now I think life is information and the systems for protecting and propagating that information. Life is in a constant struggle against the 2nd law of thermodynamics yet for about 4 billion years life has managed to pass its information for the most part intact from one generation to the next. So I don’t think we can define life in terms of chemistry or physical processes, I think we need to frame it in terms of information theory.

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  8. 8. domenico oricchio 7:55 pm 12/2/2013

    This is an interesting article.
    A man that eat only chemical element cannot live: there are necessary complex molecules, that are product from other organism (other lives); so what is the difference ( philosophical) between a virus, that use a host cells, and a human that use an environment with proteins, vitamins, and complex molecule?
    Can a potato spindle tuber viroid replicate in an environment with all the twenty-three amino acid (growth medium without cells)? If this is true, then there is no difference between the human (that obtain food with complex molecule) and the viroid (that obtain food with complex molecule): they are all life forms.
    So if the life is a not perfect self replication in an hostile environment, then a computer program that is self replicating (with a source of error in a hostile environment, that trigger the evolution) is a life.

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  9. 9. Owl905 2:19 am 12/3/2013

    Life takes action to maintain its higher energy state. Non-life does not. Computer programs and viruses aren’t life – they have no higher energy state. Fussing around with all the gray shades is semantics and tea-cup clouds.

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  10. 10. m 4:55 am 12/3/2013

    A brain with feed backward capability

    Advanced Life
    A brain with feed forward capability.

    Tbh its no wonder most people can’t define it, when its so easy to.

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  11. 11. David Cummings 5:33 am 12/3/2013

    It’s a brilliant essay but to a certain extent it falls into the category of “over thinking it”.

    You can’t say why a cat is alive and a toy is dead? Really?

    The solar system is full of rocks and ice and hydrogen and dust and methane and metallic debris. We have rovers on Mars sifting through the “dead” sand looking for what? Life?


    When and if life is found on Mars it will be a revelation that will rock the scientific world, and how much time will be spend wondering whether that find fits someone’s definition — or lack of definition — of what life is?

    The fact is, we’ll know it when we see it and it will be infinitely — infinitely — different from all the rocks and sand and debris and dust and random gases of the rest of the solar system. Infinitely different. In. Fin. Ite. Ly.

    I did enjoy reading this essay. Really. I did. But if high school teachers ever need an example of “over thinking it” to show to their students… I submit this essay as a prime example.

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  12. 12. srbeck13 8:03 am 12/3/2013

    As far as I can tell, all discussions of this issue ignore a fact that the discussions themselves demonstrate, which is that we always know whether something is or was alive as soon as we encounter it, or if we don’t it is always because of a lack of information, not a lack of definition. I don’t know of any instance in which a lack of a verbal definition has any practical consequence. To say that life doesn’t exist just because we can’t define it penalizes life for our own failing.

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  13. 13. First Nation 1:48 pm 12/3/2013

    It seems to me “science” is confused by this issue because of the basic scientific premise: “Matter is dead”.

    Why not apply “Copernican” thinking to the “life quest” question and query whether the Human centred viewpoint of science is the obfuscating the conclusions. The basic viewpoint of science is: “We humans are alive , we are the pinnacle of life (put here by god basically), things most similar to us are also alive, things not like us are dead.” is still the basic premise behind science, and religion for that matter.

    Rather than to think: all the universe is “dead”, and there is only this sliver of life stabbed in, and then search for the distinction that defines “life” from all that dead matter; I think it is more logical to say that everything (the universe) is alive, and it simply takes many different shapes. Most of which are completely alien to the human centric viewpoint.

    Tribal humans saw the lie in that thinking long ago, they could see that everything is a “live” spirit apparition within the greater life entity that is all matter. (Individual Spirits within the Great Spirit)

    Same thing Ferris Jabr is getting to really, except he concludes everything is dead, due to the leading scientific premise. If it can all be dead, why can’t it all be alive?

    Think of how the “search for life in the universe” might drastically change if the human-centric scientific viewpoint did.

    Darren Winegarden

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  14. 14. SkizD 3:50 pm 12/3/2013

    This article doesn’t even begin to tap into consciousness and who is behind an organism experiencing things. From atoms vibrating, to us being ‘fooled’ into experiencing things, must we reduce our experiences into scientific materialism? Experience is immaterial.

    Some pretty funny lines you draw between living things and inert materials. This article embodies the end-game for scientific materialism desperately clawing to explain things that still seem like magic. Life exists, you are over analyzing our experience of life. Think of letting go of long held ideas in the sciences – its like asking a hardcore Christian to consider they’ve been lied to their whole life.

    Science has a lot in common with religion when it comes to critically thinking about something outside its scope. Consciousness shall not ever be reduced to fit our current model of physics – and it probably never will. What I’m getting at here is that consciousness exists out of material that cannot be measured, and as such articles like this will pathetically try to cram it into our current status quo of reality. So dry, so lame.

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  15. 15. jackdespisesu 4:27 pm 12/3/2013

    If there is no such thing as life..then there can be no true death.

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  16. 16. SciamPhDR 4:29 pm 12/3/2013

    It’s not just life which we fail to define. In science so many things are failed to be defined: like time and space, like do we exist at all or not and what about the nature of space as in “is it continuous or discontinuous?”…

    I think the author of the article is correct if he means that whatever we call life is only an emergence of the human mind. And I would go even farther, it is all an emergence of group thought (ref. psychology).

    So now just a question: are these discussions and reflections themselves alive?

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  17. 17. donreplies 4:37 pm 12/3/2013

    I realised this for a fact once I learnt cellular automation as a part of my IT degree. There is no force needed to control anything. Life, the way we perceived for several years (as a magical energy that keeps us functioning) does not exist. Everything will work the way they are if given the specific circumstances and engineering. With living beings in nature, they evolved to be that way very mechanically through thousands of years. If programmed well, any machine can evolve into something the original programmer never imagined of.

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  18. 18. Jason O_Hara 5:40 pm 12/3/2013

    The world is not missing a science of philosophy because philosophy is merely religion with the precautionary principle implied; a relic of another era.

    I agree with this article except for your conclusion that life ‘does not exist’ because the Earth does exist. Life is a concept just as much as god, alas, it was that hook which inspired me to read it.

    Perhaps a review of existentialism would satisfy any remaining internal debate:

    Here’s one for the books; these words you now read are symbols that represent the vibrations of human vocalization which have given rise to many languages and creeds of symbols. “Life,” can never be more than the definition given to it but rather the word needs definition just as a human being does. My point is that we are a bi-product of a living planet and ultimately we exist as the result of said life-cycle. Evolution is not a tool of life but of the planet which bore life to further it’s own existence. To understand this symbiotic relationship one has to examine the concept of god, culture, history, and the evolution of the human word.

    Furthermore, what unites life my friend, is death. But that’s an old story than began long ago and without that evolutionary trait we probably wouldn’t have made it out of the warm pool that bore us. We now know it doesn’t have to be that way and just as our cell biology programmed itself to die long ago we will likely gain the ability to prolong life in ‘unnatural’ ways. What should such a thing mean to the human individual? Merely that man has conquered one more freedom for the good of man.

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  19. 19. naveen_rao 6:13 pm 12/3/2013

    I work in an industry that is trying to create (or rather, recreate) intelligence. These questions come up a lot, and I had a similar realization as yourself. I think we can also draw some parallelism from the one time (pre-Darwin let’s say) humans were considered something special from all other animals. Purportedly it was a “divine” spark that bestowed this specialness upon them. After evolution was laid out by Darwin, a paradigm shift occurred; we (humans) were no longer any different from any other animal. We exist in our current form through the same selection process as all other animals currently on the planet.
    Now, there still seems to be some sense of “magic” about human intelligence. I believe in the next 30 years or so there will be another paradigm shift; this time between humans (and other animals) and information processing machines. It will be a realization that we and all other animals are simply forms of tuned information processing entities, and the latest machines are merely another form of it.

    So much for being special :)

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  20. 20. Scottcha 6:34 pm 12/3/2013

    Excellent, thoughtful article on the continuing death of vitalism. One nitpick: It’s Thomas, not Tomas Cech…

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  21. 21. Spartan92063 7:16 pm 12/3/2013

    Great article

    Coming down to atoms that make up matter of all forms in your last paragraph after discussing in much detail about “life” – definitions, complexity and what not…good to know there are some people out there with a different perspective of the universe that we know of.

    I would like to know where you stand on the concept of “sentience”…
    would you say its covered in this article; or whether its related..

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  22. 22. wonshikee 7:42 pm 12/3/2013

    The article is well-written and I enjoyed it, but the whole premise is rather absurd.

    You acknowledge the simple fact that we know life when we see it. There is no debate required.

    So the only thing lacking is our ability to define life, not that life itself does not exist. There’s many things we can’t define, it doesn’t mean it doesn’t exist.

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  23. 23. lwhalen 9:49 pm 12/3/2013

    Thank you so much for this. I’ve spent a lot of time myself writing about this idea of this strange cut off we have between inanimate and animate. I find it to be completely arbitrary. And you so rightly pointed to what I believe to be the reason for the line – our narcissism. A lot of our problems as a species could be remedied if we remembered more often that we are just one small part of a whole.

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  24. 24. DanAdler 11:20 pm 12/3/2013

    Good article! I disagree with the claim regarding Genetic Algorithms. They are nothing like real evolution. The main reason is that they rely on a “fitness” or “evaluation” function written by the programmer. This function completely defines how things will evolve, even if we cannot actually predict the outcome. Genetic Algorithms are an OPTIMIZATION algorithm. They get closer and closer to a target function. If anything, it’s much more of a model of “intelligent design” than darwinian evolution, because it’s guided by the programmer-supplied fitness function.

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  25. 25. iceworld00 3:11 am 12/4/2013

    Even though I have thought a lot about this topic but I never reached the amount of scientific knowledge you are offering here. Moreover, while reading this article, I felt that you took the effort on my behalf with your deep analysis to offer it in a ready readable material; as a finished result.

    Personally, I mix the ‘scientific reasoning and the concrete reality’ with ‘faith and the the unseen reality’. It’s more than ‘just’ atoms.

    Thank you

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  26. 26. dadster 5:13 am 12/4/2013

    Jabir is wrong in almost all his assumptions, examples and postulates and I find it hard to accept anything he says except that it appears to be a highly skewed view arrived at from wrong premises . Then look at this assertion of Jabir . I quote ” . Subsequent experiments revealed vitalism to be completely untrue—the inorganic can be converted into the organic both inside and outside the lab.” Pray , which are these “experiments ” that revealed vitalism as untrue ? Quote a few or atleast one . Then again , how can inorganic be converted into organic without the ” adulteration” of organic with inorganic ? Give one or two examples where such conversions have taken place . Organic structure can be reduced into inorganic structure by destroying the organic property but how can it be done reverse ?
    Secondly , the characteristic quality of life- energy is the ” instinct of survival ” not necessarily the survival of one individual but in the larger survival of the species something similar to Dawkins ” selfish gene ” .This propensity is not seen in inorganic substances .
    Thirdly , while matter- based energies like heat is subject to entropy where over time the energy gets disorganized striving and seeking stability whereas life- energy which is NOT matter- based energy like electromagnetism (EM) is imbued with the propensity to get more and more organized over time bringing in ” evolution” from single felled organism to multicelled complex humans , for example.

    Matter- based energy is inherent in matter . For example, EM is in every atom of matter whereas “life- energy ” is not in every atom of matter unless you agree that everything has life and there is nothing dead or lumpen matter . Life- energy is associated with only a very few elements like carbon or ammonia , or hydrogen and oxygen which all have their origin in stars in primordial conditions even . Why is life not found in gold or silver for example ?

    Matter is needed only for
    Ife to manifest in our dimensions of existence . Matter is a scaffolding , the hardware for accommodating the software ie “life “. Like ,light which can manifest to us only if matter is present ( reflected from matter for example ) . We cannot see light,visualize light without matter ,but that doesn’t make matter and light to be the same because we can sense matter without light. Craig Venter has used organic matter to “produce” life and not independently from raw inorganic chemicals.
    Our physical or chemical scientists despite all their hard work have not so far been able to make in the laboratories even a single live cell, let alone a microbe, an insect or a plant though Nature produces live beings so profligately so continuously , so effortlessly as it were. But they have no qualms in proclaiming life is no different from non- life energy , or that life itself is an illusion without any evidence whatsoever . It’s just hubris and nothing else .

    Instead , bio- scientists should sit together and seek original paradigms throwing off those of material scientists and bend their backs and hearts to study afresh what is life which is absolutely different from all other energy forms not mislead or brow- beaten or bullied by fund raising physicists , particle physicists the worst and most domineering of their kind .


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  27. 27. bthuynh 8:22 am 12/4/2013

    I agree with srbeck13 and David Cummings here. First, just because we don’t have yet a full understanding what constitutes life it doesn’t mean we should deny it exists. This way sounds very ‘Buddhist’ to me. Second, some of the examples pointed out are not exactly solid demonstrations of the life-nonlife confusion. Did Campbell and co. explicitly mention that as long as you hit ONE or TWO items on the life checklist you’re life? No. So a crystal might grow, but it doesn’t have life because it fails most of the other criteria. More, life is like non-vegetarian food, you can have 99% greens in your dish but as long as you have a speck of meat in it, it’s non-vegetarian. So, bacteria, tardigrades, crustaceans can lie dormant and play ‘dead’ for months, years, centuries (i don’t care how long), but as long as they wake up and produce and breed and grow SOME TIME, they’re life.

    Also, life is something so marvelous (as you yourself are so fascinated with it). If in the end it is deemed nothing specially separate from non-life, that all the living things around are the same as an inert piece of rock, wouldn’t that feel kinda sad? What is then special about Earth compared to Mars? A lump of rock versus a smaller, hotter lump of rock?

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  28. 28. SciamPhDR 2:34 pm 12/4/2013

    I still tend to stand by my expression that “life” and “to live” are nothing more than words born from human group thought.

    I have witnessed animals mourning over their dead relatives and various animals tending to protect and care for other animals (like wolves caring for other species’ babies, cats playing with doves, hippopotames protecting deer from crocodile attack, ice [as in frozen water] protecting spiders and ladybirds, and stuff). History and nature are full of such examples. This means that there is something special about nature. Nature is both protective and destructive. However humans may fail to capture it in words or thoughts.

    Still, it is not because a group of humans can give it a name that we are so very special. Humanity has risen and humanity will fall and that’s a law of nature we cannot escape. This basically means that we are not so very special in the view of nature – and certainly not in the view of the universe.
    Remember Shakespeare (ref. Romeo and Juliet): “what’s in a name that which we call a rose by any other name would smell as sweet”. To me this is the first well known recording of the relativity theory AND it even relativates the words which emerge from group thought – like life, time, existence and on and on we go.

    I refuse to go into a discussion about god (Jason O_Hara & First Nation). I have made a manuscript called “A Universe From Scratch” and from that point of view god is not needed… BUT as not everyone agrees, god may be needed to keep humans living peacefully, harmoniously and respectfully. So, if you’re anything like reasonable and smart we better shun discussing about god.

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  29. 29. rambansal 3:13 pm 12/4/2013

    It is a continuous chain from minerals to beasts, with vegetation and animal worlds including humans lying in between, based on who eats what. For humans, ayurveda recommends full dependence on the vegetation world, hence marks those who eat animal flesh as beasts. Full discussion on this view of Ayurveda is available at

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  30. 30. Marc Lévesque 3:17 pm 12/4/2013

    Some thoughts.

    “rather, we will never find some clean dividing line between the two because the notion of life and non-life as distinct categories is just that—a notion, not a reality”

    If I follow, you mean there are degrees of life in everything, that some things have more of it than others, and though life may be poorly and loosely defined you still are implying it is a cogent property.

    “My conclusion: No. In fact, I decided, life does not actually exist”

    If I see life as a word like size or height, and things like size or height don’t actually exist in and of themselves, then I can agree.

    Moreover, if, while looking at the word life critically we use words like exist, thing, or reality, we should be treating those words with the same discernment as we are treating life.

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  31. 31. editorz 3:47 pm 12/4/2013

    Can life be understood through science-knowledge? If so, what will human beings or automatons of the future do with their curiosity? Isn’t the nature of knowledge to add more and more indefinitely? Then, is life infinite, to allow curiosity going into forever and ever? If life is infinte, can’t be understood as a whole? Do we need a infinite brain to do so, to be omniscient biologists? That is, will current human beings die without a complete meaning, whithout understanding? Without any more than limited trivialities, memories and theories about the universe that death will end absolutely? Along these lines, to go on questioning, I would like to recommend a hard-funny book: Bioquestion and the mechanical answer. About life and obviously, about death. The raw end of everything.

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  32. 32. udaihasan 9:25 pm 12/4/2013

    “Fire, too, consumes energy ”

    does fire consumes energy or fire in itself an energy that have been released ?

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  33. 33. 106Caden 12:54 am 12/5/2013

    I thought this article is strong proof that human beings over think the ways of the world, rather than embracing them. as Google’s definition of the word life states: “the period between the birth and death of a living thing, esp. a human being.” But there is much more to life than just that, especially human life. what makes up life are the events we experience, good and bad. The accomplishments we make. If the only reason we exist is to simply continue our existence, then our breath is nothing more than a meaningless clock to our time of death. I believe people like Professor Jabr need to stop asking the complex answers and start answering the simple ones. overanalization and lack of emotion are two things that make us lose our basic humanity.

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  34. 34. batubattan 2:42 am 12/5/2013

    very nice article, thank you.
    yes, it will always remain an impossible task for us to define anything with the mechanism we try to define it (by sense perceptions/the brain/by thinking..or whatever word we ant to use). We can not separate (or try to describe or try to define) anything, or any-thing, from its environment. The root for this “problem” lies in how we perceive what we call the world; by contrast. Life is awareness of contrast. Our “understanding” (you can call it consciousness) of contrast creates and generates all that we ever do and think as humans, but it also makes us think that separate (i.e. definable) things or events exist.

    This article was very good, very clearly and well reasoned. there are a lot of other good writings too that touches the subject, one would be for example alan watts “the book”

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  35. 35. mariannaz 3:16 pm 12/5/2013

    Basically everything is just a concept, and yet we have a dire need to keep coming up with them, and then fight to defend one concept over another to our deaths. I guess that clinging to our concepts gives us a sense of security. The other option is to simply live, while continuing to explore this beautiful world that we live in.

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  36. 36. choppam 3:39 pm 12/5/2013

    The article is refreshing, lucid, and unprejudiced. An excellent example of an informed and critical mind looking at what is and asking questions.
    So what I see as a Marxist is a “modern Western” mind backing arse-first out of its padded cell of Enlightenment (Kantian) agnosticism (we can’t know nuthin’) and its cruel leather thongs of medieval and older obscurantism (“divine spark”, “mystery of life”, “vitalism”, whatever).
    Essentially, Hegel, for all the idealistic appearance of his presentation of the spirit and the absolute idea and so on, got here first. Kant wiped out the old metaphysical divine certainties that pre-empted thought before the French Revolution, and then Hegel wiped out Kant’s all-too bourgeois scepticism about our ability to actually know “things” – ie our world and ourselves in it – to the core.
    Fortunately for the world, but unfortunately for Western Science, Hegel’s reason-driven and scientifically irrepressible thought juggernaut (especially the Science of Logic, 1816/32) was assimilated by Karl Marx and “turned on its head”. This produced the fundamental analysis of modern capitalist society in “Capital” and the equally necessary and logical practical commitment to resolving the contradictions in which capitalism and its partisans have immired human society.
    I wrote “fortunately for the world” because Marx’s materialist take on Hegel is still the only coherent scientific and philosophical current capable of guiding humanity beyond the confines of capitalist dogma and insanity (weapons and luxury goods given priority over the most basic needs of all humanity). I wrote “unfortunately for Western Science” because this institutional Big Science is totally in thrall to the priorities of the ruling class that owns and runs its universities and weapons laboratories etc, and any questioning of given priorities and fundamentals that might hint at a non-obscurantist, human and social understanding of our world and our active practice in it immediately runs the risk of defunding, dismissal, and exclusion from the profession. Just count the heads – for every civilized critically minded Einstein, a myriad of time-serving Jobsworths in the Werner von Braun mould. And that’s only the active cadre in Science. Count the radical, socialist, non-Kantian, non-obscurantists among the administrators! (Yes – him, over there, cowering in the closet!)

    Hegel and Marx never grew tired of insisting that the truth was the most powerful weapon around, and William Blake expressed their attitude very clearly:
    “Truth can never be told so as to be understood, and not be believed.”

    This article is very understandable, and it will be believed and followed up on. Great work!

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  37. 37. SciamPhDR 5:08 pm 12/5/2013

    I very much like all of your remarks. I believe I can justadd on more:
    There really are three universes:
    1) the comparative universe which is understandable by us humans because we compare everything – basically to our own bodies
    2) there is the absolute universe. This is the universe that doesn’t “care” about who we are or what we think or even if we exist or not
    3) the universe we create in our own minds. Maybe this is the most relevant for it disappears when we are dead. When we die – if you count out afterlife of course – the universe will cease to exist all together because there is nothing relevant any more to compare.

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  38. 38. silverfeet 11:01 pm 12/5/2013

    since reading through all this vivid information on the meaning of life, it begs one question that would explain life. what is death? Does everything really die,expire or
    does it change to something else that is still alive?
    I wounder!

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  39. 39. wherrera 6:39 pm 12/6/2013

    Long comment here:

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  40. 40. aquaorbis 12:00 pm 12/7/2013

    Fascinating concept. Thanks for the post.

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  41. 41. brs04wsc 6:39 pm 12/7/2013

    I like the article, but the conclusion needs some help!.

    This is an example of the fallacy of the beard. Beards, really as there are several continua – I’ll conflate them for simplicity into a unitary definitional criteria.

    Your proposition is that living cannot be distinguished from not living because the placement of a definitional line cannot be drawn between the two. But the exact placement is not necessary for the two categories simply to exist in a meaningful way. The name of the fallacy (also called the continuum fallacy) come from someone trying to distinguish stubble from a beard. At what exact point of growth does this transition happen? We can’t be sure, so a ZZ Top beard and one day growth aren’t categorically distinct.

    IOW, not knowing exactly where the definition of life lies does not mean the distinction doesn’t exist.

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  42. 42. yrast 6:00 pm 12/10/2013

    I don’t see why life shouldn’t be defined as:

    “A local entropy ratchet with a Kolmogorov complexity greater than some small fixed number β.”

    The choice of β allows for the threshold to be chosen such that crystals and batteries can be excluded at our discretion. We could also take into account the mechanism, (or structure, or level…?) by which entropy is being driven in reverse, so that in the case of multicellular animals entropy is decreased both on the individual cellular level, and on a greater overall body level, and they both have individual lives, one dependent on the other. Critics might say our choice of β leaves the definition arbitrary, but so what? Somewhere between a cloud of hydrogen atoms and a human brain it would be useful to draw a line to denote this phenomena we’ve been calling life — a good definition would be useful in a variety of situations, say, from declaring a person living or dead, to allowing us to proclaim we have or have not found life beyond Earth.

    And this definition allows us a great degree of control over which phenomena precisely we include or exclude in the word life, β can be chosen to include or exclude crystals, or batteries, or possibly even viruses (though maybe not without interfering with bacteria or archaea).

    So to clarify a bit, both crystals and simple proto-cells (fatty acid membranes, or vesicles), decrease entropy in the immediate vicinity of their ‘bodies’, but crystals have very low Kolmogorov complexity, because they contain a great degree of repetition and symmetry. Organic molecules on the other hand — like random noise — have rather high Kolmogorov complexity. Unlike random noise, organic molecules have a high degree of order as well. So life is a mix of great complexity and great order, whereas crystals are just great order, and noise is just great complexity.

    Even if this definition has holes, I think computational complexity theory (and computer science more generally) should have a lot to say about this topic.

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  43. 43. Little Katy 11:37 pm 12/10/2013

    I agree that criteria of life is a human construct. What this article does for us is frees us to consider expanding what we feel is alive. Many indigenous nations throughout the world extend the definition of life to the earth. The earth is seen as a living organism that lives in relation to us, not only alive but to be treated with reverence. Unfortunately, it is been customary in Western culture to approach the earth in the category of not alive i.e. not “like us” so much so that the earth is seen as something to be dominated and consumed.

    Let me give some analogies the bring Earth to life:

    Some of Earth’s components, such as sand and rock, appear lifeless, may merely be equivalents to parts of our body that appear the same: our hair and nails are lifeless protein, the top layer of our skin is empty keratinized dead cells. Do events like hurricanes, tornadoes, earthquakes not give the Earth an abundantly alive personality? Or how about the sunrise and sunset and a soft breeze on a beautiful day, does that not make us ponder life as much as the curiosities of a cat do? Is the layout of the earth’s resources not reminiscent of our anatomy- rivers that deliver nutrients to much needed areas as do our own blood vessels? The constant and predictable generation of its spinning on its axis not like our heart’s capability to sustain its own electrical impulses? Is the earth not constantly evolving- think of a time when the level of oxygen on the planet sustained mosquitos the size of eagles? And despite the fact that it cannot replicate itself by producing a daughter cell or child, when our Sun will undoubtedly nova, will the Earth not explode and donate life to other parts of the universe, upon falling on other planets?

    This isn’t just food for thought. Thinking in this way can be useful for our survival on this planet and the continuation of the biosphere.

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  44. 44. cypherhat 2:38 pm 12/12/2013

    Loved the article… and at the same time, I felt like I was reading the best example of the fallacy of the beard ever published.

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  45. 45. vapur 1:18 am 12/14/2013

    Words are life. When you put together the letters to give meaning to words, you can string them together and create sentences. This can be taken literally and metaphorically.

    A book, for instance, gives rise to a world that doesn’t exist in our reality, but nonetheless has a life on its own (within our Universe, which may be a set-theory problem). Another example is Messenger RNA stringing together proteins to make a greater organism function. Even atoms combine to form larger structures that enable planets to form and light to shine.

    Each minute part is a letter that combines to form a complete whole, a word to a sentence to a paragraph to a story.

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  46. 46. RalphD 9:23 pm 12/15/2013

    It should not be necessary to insert Darwinian evolution into a definition of life. Many individual organisms are certainly alive, yet are not able to reproduce. It would be artificial to exclude them, based on the possibility or impossibility of some speculative future evolution.

    I think yrast is looking in the right direction. I’d like to see his or her definition of the term “entropy ratchet,” but I think it refers to the propensity of some systems to retain and even gain complexity without supervision. Clearly, that really does happen.

    It is important to remember that inside our bodies, every process proceeds spontaneously — in the thermodynamic sense of a reaction tending to occur in a particular direction, rate unspecified. We know this is a valid description of the world we find, but at the same time it seems impossible to imagine it “just happening.”

    A possible key to the conundrum might be found by considering chemical cycles. Where certain fluctuating energetic and entropic surrounding conditions prevail (think night and day), it is not too difficult to imagine a single chemical cycle becoming at least intermittently persistent. Consider, then, multiple chemical cycles arising in the same small region. The magic (kidding!) begins when several such robust cycles start interacting in various ways without disrupting each other. A relatively simple cycle becomes part of a suddenly complicated environment. Only then, I think, can we envision complexity growing without supervision.

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  47. 47. domenico oricchio 7:18 am 12/16/2013

    A beautiful idea.
    I am thinking that the ideas are life, when there is a person that expresses they, and someone else that read, understand and change they a little.
    There is an evolution of the ideas, some become viral, other die, other are shared with many transmission system; they are is not pure informations, but concepts.

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  48. 48. mejimenez 6:51 pm 12/16/2013

    Not even a mention of autopoiesis as an alternative way of defining life? The unique feature of a living being is that it is an entity that produces itself. It is a unity embedded in its environment yet maintaining its distinctness from what surrounds it. When it can no longer maintain its distinctness from its surrounding environment it ceases to live. From Maturana, Varela, Uribe (1974) as quoted in “Mind in Life” by Evan Thompson:

    The autopoietic organization is defined as a unity by a network of productions of components which
    (i) participate recursively in the same network of productions of components which produced these components, and
    (ii) realize the network of productions as a unity in the space in which the components exist.

    Consider for example the case of a cell: it is a network of chemical reactions which produce molecules such that
    (i) through their interactions generate and participate recursively in the same network of reactions which produced them, and
    (ii) realize the cell as a material unity.

    Thus the cell as a physical unity, topographically and operationally separable from the background, remains as such only insofar as this organization is continuously realized under permanent turnover of matter regardless of its changes in form and specificity of its constituent chemical reactions.

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  49. 49. domenico oricchio 7:25 am 12/18/2013

    I am thinking that if a body of knowledge is life, then after a while there is not evolution, when the target is reached (like a perfect dna don’t evolve more, with identical individuals, in a hostile environment); for the Physics the Theory Of Everything (if the goal is obtained, the Physics don’t evolve more, the dead of the Physics: no more Nobels), for the Chemistry the atomic technology (synthesize complex molecules like dna, or new atoms), for Medicine the Cure (genetic cure for each disease), the Computer Science the Artificial Intelligence (programs writes themselves).
    The only knowledge that seem – to me – not have limits, are Mathematics and Philosophy: it is greater the world of the thoughts of the real world.

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  50. 50. hatemnajdi 9:14 am 12/18/2013

    Very good article. However, is the debate about the existence of life or its definition? If we could not arrive at a satisfactory definition of life, would that dismiss its existence? Weren’t the solar system, the relativistic and quantum effects, the galaxies..etc. existing before their discoveries and characterization?
    I think the title of the article needs reconsideration.

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  51. 51. dB333 2:27 pm 12/19/2013

    @dadster comment 26 (reply not working right now)
    An example of inorganic chemicals being made into organic chemicals in the lab:

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  52. 52. dB333 2:33 pm 12/19/2013

    @First Nation, comment #13 and others,
    It seems that many read the catchy title of the essay and couldn’t get it out of their minds while reading the article.
    The author is not actually saying that life doesn’t exist, but rather that he doesn’t see a clear differentiation or distinction between “life” and “non-life”. His line of reasoning does not lead to “everything is dead”, nor does he say as much. In fact, he only uses the word “dead” twice, and only in reference to others describing things as such.

    Did I read the same article as everyone else?

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  53. 53. JanVen 9:16 am 01/9/2014

    It seems obvious that everything in the universe shares the quality of “existence” whether we would call it alive or not. What does it mean to “really” exist? I suppose that the point of the author is that there is no fundamental boundary line between life and death. I think this is something we see everywhere: if we look close enough the boundaries between the distinctions we make seem to disappear. But it all a matter of perspective, this fact cannot deny that our distinctions serve a purpose, and that there is some difference between life and death, even if it is not THE fundamental thing in the universe. If we look close enough there is also no difference between solid, fluid and gaseous states, or no difference between 10 grains of sand and a dune, or no difference between biological species. Does this mean all these distinctions make no sense?

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  54. 54. avaloketeshvaro 10:00 am 01/26/2014

    I agree with Bthuynh, that it would be interesting to look at life from the perspective of Buddhism. There draw the line: living – this is what feels responsive, want to live. There on Buddhism only three states in the universe: the mind of living beings (consciousness), the mind of a Buddha and things (matter).
    I’m from Russia and a Christian, but my worldview Buddhist …

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  55. 55. Runewolf1973 1:31 pm 02/11/2014

    Good article, thanks!

    The way I see it is there is no such thing as Life as some special property which separates animate from inanimate. There are only those forms of matter which are more or less lifelike based on the complexity of their interactions. All matter is animated due to the fundamental forces of nature, there is no such thing as “inanimate”.

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  56. 56. Bioetica 8:31 am 03/12/2014

    This work highlights some of the problems and paradoxes that occur when one tries to define what Life is, but ignoring some key aspects. First of all we need to distinguish, both philosophically and scientifically, between the definition of Life and the criteria necessary to ascertain the state of being alive. Also, we need to assign levels or degrees of Life: for example from a corpse (obviously dead) we can extract transplantable organs which are very much alive. Moreover, the criteria for ascertaining Life is likely more probabilistic than deterministic, as is common in other complex phenomena.
    Apart from these aspects, the author seems to draw a puzzling conclusion that would sweep away all problems and paradoxes by simply stating that there is nothing to define, in that Life is simply an emergent characteristic of complex matter. Such conclusions are reminiscent of the rather grotesque idea of The Theory of Everything which some physicists think will enable us to understand everything.
    Our conclusion is completely the opposite, in that Life does exist. It is only our inability to define it completely due to our lack of understanding and not self-consistency of our logic and theories. Thus a complete understanding of Life will remain elusive.
    The frustration we suffer from our difficulty in defining Life should not be arbitrarily removed but limited thanks to our growing knowledge of biological systems and by humbly accepting that there is much we do not know and may never know.

    Carlo Petrini (Istituto Superiore di Sanità) and Nicola Pugno (Università di Trento)

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  57. 57. Bioetica 10:12 am 03/12/2014

    This work highlights some of the problems and paradoxes that occur when one tries to define what Life is, but ignoring some key aspects. First of all we need to distinguish, both philosophically and scientifically, between the definition of Life and the criteria necessary to ascertain the state of being alive. Also, we need to assign levels or degrees of Life: for example from a corpse (obviously dead) we can extract transplantable organs which are very much alive. Moreover, the criteria for ascertaining Life is likely more probabilistic than deterministic, as is common in other complex phenomena.
    Apart from these aspects, the author seems to draw a puzzling conclusion that would sweep away all problems and paradoxes by simply stating that there is nothing to define, in that Life is simply an emergent characteristic of complex matter. Such conclusions are reminiscent of the rather grotesque idea of The Theory of Everything which some physicists think will enable us to understand everything.
    Our conclusion is completely the opposite, in that Life does exist. It is only our inability to define it completely due to our lack of understanding and not self-consistency of our logic and theories. Thus a complete understanding of Life will remain elusive.
    The frustration we suffer from our difficulty in defining Life should not be arbitrarily removed but limited thanks to our growing knowledge of biological systems and by humbly accepting that there is much we do not know and may never know.

    Carlo Petrini (Istituto Superiore di Sanità) and Nicola Pugno (Università di Trento

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  58. 58. PaulNed 12:05 pm 03/17/2014

    At least two big logical errors in Jabr’s piece here. One, our failure to find a physical definition of life doesn’t imply that life isn’t a real, mind-independent feature of the world. Instead, life might be a non-physical feature. NB: The experimental work that undermined vitalism doesn’t affect this possibility, since that work just showed that organic material could arise from inorganic, not that life isn’t non-physical.

    Two, even if there is no definition of life at all, it doesn’t follow that life is a merely constructed concept. There are many real features of the world that lack definitions. I explain Jabr’s invalid reasoning here in a response to the shorter version of his piece that recently appeared as a NYTimes op-ed:

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  59. 59. moreorless 2:08 am 05/12/2014

    -a zillion ways to tell one life aint so -is pourin a 2 gallon of lemonade into a glass -it keeps overflowing -fun to observe. oh, cosmos and eternity are grand illusions!

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  60. 60. Vish10 7:20 am 06/30/2014

    Ever heard of aversive stimulus? Every thing that has been associated with life goes through this stimulus, even bacteria. Plants may not have this but they nonetheless have been researched to have felt pain but they sadly cannot express it. Maybe this should answer your question as to the one thing that unites living things and commonly differentiates them from the non-living.

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  61. 61. headihold 12:12 pm 10/18/2014

    I find this article very interesting. I’ve been looking for some time for a scientific text that would mention some philosophical implications of the difficulty in defining “life”.

    Along with few previous commentators i ask myself these non-scientific questions:
    If life is only a concept, are we alive? Do we die?

    thank you

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  62. 62. Armandofly 8:01 pm 10/25/2014

    We can say that life doesn’t really exist as well that everything in the universe may be considered life. If the difference for somebody resides in the consciousness or soul I think that we cannot be sure that a rock or a star doesn’t have one. Eventually the definition of life would remain unattainable because our brain is not designed to comprehend such concept.

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  63. 63. thestar 7:53 am 12/21/2014

    Good Article…. But according to me the author missed 1 point.

    A living thing Performs actions Because It wants to, and has full command and control over his actions. It can change however or whenever it likes.

    While a computerised machine using artificial intelligence, Performs actions because a human wants it to… In other words it is programmed to do things.. even its way of doing thing is defined by a human and it can change only if someone wants it to.

    If no one on ‘EARTH’ has found this difference than “I” have..

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  64. 64. Zamzuri 6:50 am 12/22/2014

    Interesting articles. Lately, I question myself “who I really am”?; where was the point of origin?…I learnt medicine and brain for years but now shifted to physics, universes and many more to answer those questions. But still could not satisfactorily answer my previous questions. I turned to religious books…commonly read by many. Still no answer. Then I opened the “old books” learnt by few (including my late father in 1960s); ‘few’ because the contents are mostly contradict or deeper to what many already knew. They talk about deeper translation of Quran (religious book for muslim); which according to these few scholars, the deeper translations (got 7 layers of meanings) are mostly ‘directed’ to self not ‘others’. Currently, most talking only the first layer. It is like ourselves, containing zero element (body) and infinity element (spirit): these two numbers are opposite but yet exist in ourselves!!!!. Many just talk about zero element (very few talking about infinity element: because the meanings are opposite but interestingly, could also be true). To be short; from my search studying the old books, I noted the same ideas as the author here…Living things are actually ‘not exist’ (‘like’ shadow [all in universes] and owner of the shadow [god]) and all (animate and inanimate) originated from ‘one’ = nur/light. The books also mentioned ‘all’ have spirit (even rock, sand etc – i.e atoms and oscillations; also count are ups and downs items (respiration, heart rate, blood pressure, peristalsis, brainwaves, action potentials etc….are indirect manifestations of soul; when dead all ‘flat’). These inquests directed me to note that the brain/CNS is in fact in “microgravity” space; against ‘gravity’. Further details to my few articles on these (based on old books and sciences in 2014) can be accessed online at “” and “″. just sharing the thought n these can direct us towards consciousness etc.

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  65. 65. ProtoBiont 8:50 pm 01/9/2015

    There’s a number of flaws in this logic, but I’ll focus on three in particular: The argument that viruses contain all the same “life-defining properties” as a parasitic worm, the argument that crystals and fire contain the same “life-defining properties” as things that are normally considered to be “living,” and the concept that an organism that goes through long periods of hibernation is somehow the same as something that is not alive.

    Viruses are widely considered to be non-living, but organized, clusters of organic matter that “evolve” only by use of external hosts. What differ viruses from living parasites is not the ability to continue their life without a host, but the mechanisms by which the parasite manages itself, and the lack of such mechanisms in the virus.

    A virus, for one, does not have a mechanism for metabolism. Parasites do. The source of food for a parasite may be another organism, but by that logic, we could just as easily say that any heterotrophic organism (an organism that lives by consuming other organisms) is therefore no different from a virus, but this is a vast oversimplification, and doesn’t get to the root of the issue: Organisms contain the mechanisms required to metabolize things and viruses don’t.

    Another issue with considering viruses to be “alive” is that they have no method of self-replication. They must hijack the mechanisms of a living cell to replicate themselves. On their own, there is no way for them to replicate. Even a parasite without a host can potentially reproduce, and the mechanisms by which they do reproduce are still self-contained, and created by the organism that is reproducing, and not by the host.

    Crystals and fire are not alive, nor do they contain the same properties attributed to life. Organization and growth are components crystals have, yes, but the organization of crystals does not allow for self-replication, nor does it allow the crystal to metabolize things. While there have been recorded experiments of crystals that can metabolize things, the idea of self-replication is still something that remains to be seen. The idea that there could be a crystal structure formed that would be defined as “alive” is not terribly far fetched, however. I could similarly say that a lump of coal isn’t by any means alive, and it is made almost exclusively of carbon, therefore large organizations of carbon must therefore not be alive, but yet here I am, typing this response, very much alive :) . Dispelling a concept simply because it “seems preposterous” without looking at the evidence is bad scientific practice.

    Fire, on the other hand, is not a system, but rather a large, amorphous collection of plasma (“excited” gas particles, or “ionic” gas particles), light (given off by the plasma), and heat (formed by the combustion reaction required to make the fire). Believe it or not, metabolic reactions utilize combustion reactions -all the time-. That’s why it’s amazingly accurate to say that when you exercise, you are LITERALLY burning fat. In other words, the reaction that creates fire is actually quite essential to life. However, this does not mean that fire is life, as fire lacks a definitive cell structure, it does not have a system for self-regulation, and it cannot adapt to its surroundings.

    Lastly, the issue of long-term hibernation in organisms: This confuses the concept of “dead” with the concept of “non-living.” While it is accurate to say that a person COULD be dead if their heart stops, and by many medical definitions, they “are dead,” this is a rather superficial definition, and doesn’t really get into the heart of what “death” really is. Death is defined as damages to the organism’s vitals that cause it to cease functioning at a cellular level that cannot be reversed. Many consider a person to be “dead” when their brain ceases functioning, however, because the brain is where what we perceive as being that person resides. While this doesn’t fit the idea of biological “death,” it is a human definition and hardly a pointless one, as keeping someone alive in much the same way as a flower in a vase filled with nutrient-rich water, is easily considered to no longer be a person, but a person’s body being kept alive.

    However, while it is true that the leaf is easily considered to be “alive” while maintained in a lab, it is hard to say that it is an organism anymore. A leaf, on its own, cannot reproduce, and will eventually die, as all leaves do. The leaf, therefore, is not an organism, but rather living tissue from an organism. There is a distinctive difference in this definition that is important not to miss – tissue is not “alive” in the same sense as the organism it came from.

    This gets into the idea of multicellular organisms really just being large colonies consisting of a hierarchy of organized groups of highly specialized member organisms, but this does not take away the fact that they are alive. However, the difference between a colony and a single, multicellular organism is that the colony members can all, individually, fulfill the requirements for the definition of a living organism. A tissue sample of a multicellular organism, generally, will not. If it does, then it is, itself, an organism. To claim otherwise would be to say that if my gall bladder were removed that I would no longer be human because I am no longer “part” of the gall bladder. The fact is, I don’t need it to survive. While this would claim that those who suffer from impotency are no longer considered “alive,” defects in functionality do not take away from the fact that they are still produced as a living organism, the same as everyone else. This is, in fact, a very important distinction.

    The concept of “non-living” matter vs. “dead” organisms is a difference between an amorphous collection of substances that may contain matter that was once used in life vs. the still primarily organized remains of an organism that was at some point in the “recent” (relatively speaking) past was once alive.

    For example, a clod of soil is not alive, nor is it dead, though it is teeming with life, and contains loads of matter from dead organisms. On the contrary, a rotting deer carcass is dead because it is still significantly made from the form of the living organism it once was.

    While the definitions of life are fairly trivial, somewhat meaningless, at some levels, and grow more and more blurry as time goes on, it is an important part of human understanding that we find ways to abstract complex problems better and with more concrete distinctions, as time goes on, and the lack of a non-complex explanation for what defines life as different from non-life does not make a sound argument for the non-existence of life. It simply means we should probably take some time to reflect on our definitions and update them accordingly, as that is the scientific way.

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  66. 66. ElyseHogard 3:53 pm 01/23/2015


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