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New Giant Viruses Further Blur the Definition of Life
- jimmahoney 9y ago"Life. Don't talk to me about life." - Marvin. http://hitchhikers.wikia.com/wiki/Marvin http://hitchhikers.wikia.com/wiki/Marvin
- XorNot 9y ago1 micron is amazingly large. 300nm is about the threshold to resolve a particle under light microscopy, so these things would just be there - you could use a pipette and push them around.
- deleted 9y ago[deleted]
- WillReplyfFood 9y agoDefinition of Life: Anything that gets away with Concept or Pattern Immortality.
- ozy 9y agoMy personal definition of life: self-replication with unlimited heredity. self-replication: something can make a copy of itself. unlimited heredity: when "information" is added, it is copied along, even if it does not contribute directly to the replication process itself. Implied in the definition is variation. And in the bigger view, that all replicators are under pressure to do so well, or be outcompeted on resource usage etc., and disappear. While a virus depends on a rich and active environment to work, they clearly fall into that definition.
- tehwalrus 9y agoThis definition includes computer viruses. Did you mean to?
- ozy 9y agoSortof. But with a few caveats. 1) most computer viruses don't randomly vary, and thus don't have a learning effect, miss unlimited heredity. 2) they are not physical life, so the relevance is not the same as their chemical counterparts.
- zaarn 9y agoI wonder what would happen if we taught a computer virus to modify itself without restriction. Of course, most of those viruses would probably just be rendered inert, printing a lot of segfaults into the kernel console.
- novia 9y agorelevant radiolab episode here: http://www.radiolab.org/story/shrink/ http://www.radiolab.org/story/shrink/
- tensor_rank_0 9y agoanyone hear the theory that cytomegalovirus is a fragment of a gigantic prehistoric virus? a nurse friend heard about the theory in his medical microbiology class but I haven't been able to find much online.
- emerged 9y agod-d-dino virus? non-life finds a way. Fascinating if true.
- sebazzz 9y agoI never understand why viruses are not life. Bacteria are life because they are essentially a single-cell organism and act like any cell in our body: they consume energy and produce waste. Viruses may not be a cell, but they can be damaged, they die, and they appear to be more than a simple chemical process.
- SllX 9y agoOur understanding of life, viruses, and the relation between them is incomplete which means our definitions and lexicon as they are interrelated is also lacking in resolution. Before the discovery of these Giant Viruses as I guess we are calling them now, you used to be able to make a useful distinction between cellular-based life, and viruses. Viruses were mere packets of information as far as our best understanding went with very simple mechanics. Cells are more complex, with a useful distinction being made between prokaryotes and eukaryotes when necessary, but each could be easily identified as being made up of one or more cells. As our understanding of life improves, so does our useful observations into that murky grey area between life and not-life, and I suspect we will have to potentially extend the definition of life but come up with a vocabulary that more usefully delimits the forms it can take from its most simplest forms into the murkier grey area where viruses start to resemble cell-based life. Science is a work in progress, and so must be the scientific lexicon. Consider further your use of the word "die" and is that really the word you would use when a virus expires? Maybe, if you consider them to be alive in the first place, but you might use the word "destroy" if you considered them to be more like an object, or at least not alive.
- Santosh83 9y agoPerhaps when we consider that viruses are unable to form complex structures like tissues, organs and entire organisms, we must rethink if they're the same level of "life" as cells? I don't think a single definition of life is useful or might even exist, just as I don't think a single universal physical theory is possible.
- jayd16 9y agoWould you consider prions to be life?
- 9y ago
- kleer001 9y agoNature is not constrained by human imagination.
- meri_dian 9y agoHere's a controversial view, but any good comments section needs a few of them: Viruses are no more "life" than bacteria are "life" or amoeba are "life" or ants are "life" or mice are "life" or humans are "life"... We're all just chemical machines, nothing more nothing less. Giving the word 'life' some special significance is misleading and confusing. In order to not confuse ourselves we should be talking about functions and descriptions of those functions as implemented among chemical machines. Do viruses reproduce? Yes, by hijacking cellular machinery. Do bacteria reproduce? Yes, by cloning themselves. ... This sort of thinking about the world allows us to stay close to reality without abstract and ultimately meaningless distractions like 'life'. Heaving the burden of abstraction onto 'reproduce' is still dangerous, but much less so than allowing 'life' to lurk as an abstract category in our minds.
- filoeleven 9y agoIs this not just picking a different abstraction? What is a “chemical” besides a collection of atoms? What is an “atom” except (some hand-wavey quantum stuff that I certainly don’t understand)? Why give primacy to the chemicals over the atoms or the quantum field? We could go the other direction too, and consider it significant that we are a tiny part of a giant living body that is the planet. Does it stop there? Could we comprehend it if Earth itself was a part of some vast active living intelligent system, in the same way that we believe a bacterium or a cell cannot conceive that it is part of our own human body, seeing it simply as “the environment”? It all gets fairly philosophical pretty quickly. I certainly don’t have any answers, but I will say that I find it a little suspicious how when we move far enough in any direction from the scale we ourselves operate on, our understanding of how things work devolves rapidly towards relatively simple deterministic or probabilistic equations, while our own life experience is rich and rooted in desires and decision-making.
- ajnin 9y agoBy that definition you could say that pretty much anything that does something is a machine. A computer is an electrical machine, the Sun is a physical machine ... We choose to give specific names like "computer" or "star" or "life" to physical phenomenons which fit a particular definition. It's mostly a way for us humans ot communicate and think about it. Life exists because we made up a word for it.
- nyc111 9y agoI consider legal entities such as corporations to be living organisms. So I don't agree that life is limited to organisms with a visible (biological) body.
- rhinoceraptor 9y agoI consider Oracle to be a giant virus.
- kitd 9y agoWhile true in principle, natural organisms tend to be vastly more complex than even the largest corps, and complexity leads to emergent behaviour that you wouldn't see in a hierarchical human organisation.
- filoeleven 9y agoHow about a culture?
- jacobush 9y agoHm, you say that like it’s self evident. Don’t corporations do things alone humans couldn’t?
- kitd 9y agoThat's not really emergent behaviour. eg the decision making of an organisation is simply the decision making of it's personnel. Complex organisations can self-organise even though the individual parts have little understanding of their position in the structure. A better simile would be societies at large, and the changes in things like housing markets or stock markets, driven by individuals who are only guided by their own private interests, not those of the market as a whole.
- nyc111 9y ago>the decision making of an organisation is simply the decision making of it's personnel. This is also true for animals, including humans. Most of our decisions are made by micro-organisms in our gut, by our microbiome. There are other decision-making centers as well. The self is not even aware in most cases that he/she is just applying a decision that was made for him internally.
- mgeorgoulo 9y agoI bet every biology student has struggled with the introductory "what is life" chapter, full of conflicting definitions. It is so difficult to define life because there is nothing to be defined. There are complex stuff and simple stuff. We tend to call things that exhibit a certain degree of complexity "alive", but that's just a word. Can't remember who wrote the perfect definition of Biology: "The study of complex things". There's a great deal of wisdom in that.
- nonbel 9y agoYes, I logged in to say the same. There can be mutliple definitions of life, each useful for different purposes. It is like those people trying to figure out how many types of cells there are in the human body. There is no "right" or "true" answer, only useful ones. All these categories are artificial.
- tome 9y ago> Can't remember who wrote the perfect definition of Biology: "The study of complex things". There's a great deal of wisdom in that. Human society is complex, but it would not normally be considered biology.
- woodandsteel 9y ago>Human society is complex, but it would not normally be considered biology. Reality is organized in levels of complexity. Society is composed of living creatures, so at least you should say it is life-based. The big debate is how and where you draw the line between the non-living and the living.
- skissane 9y agoTrying to define "life" is one of the central questions of the philosophy of biology. And the positions one takes in the philosophy of biology are inevitably going to be influenced by one's metaphysical positions regarding the problem of universals. A nominalist, a Aristotelian realist, a Platonist (etc.), are all going to approach the question "what is life?" differently. Sometimes when people discuss this topic, they assume a certain approach to metaphysics without making that assumption explicit (indeed, they may not be aware that there are genuine alternatives to their personal metaphysical positions.)
- nonbel 9y ago>"Trying to define "life" is one of the central questions of the philosophy of biology." If this is true then "philosophy of biology" is a likely a total waste of time. It is obvious that life vs non-life is an artificial categorization that humans use because it is useful to them.
- skissane 9y agoYour response presumes a particular philosophical position. When you call life "an artificial categorization that humans use because it is useful to them", you are espousing the nominalist solution to the problem of the universals, and applying that to biology. Even while attacking the philosophy of biology you are actually engaging in it. Nominalism may be "obvious" to you, but it isn't obvious to everyone. Just because someone thinks something is "obvious" it does not automatically follow that it is true. Have you given serious thought to nominalism's alternatives, such as moderate realism (Aristotelian, Thomistic or Scotistic); or Platonism?
- nonbel 9y agoThere isn't any deeper philosophy behind what I said, it has nothing to do with how things "really are". Just go categorize some stuff and see what happens. Is a bottle cap a "coin"? In some cases, sure that could be. In others, not at all.
- ntumlin 9y ago
- Isamu 9y agoWasn't it always taught that an active metabolism separates living from nonliving? This brings up other questions though about how complex a virus can be. And if they can be arbitrarily complex, will we rethink our definitions?
- antiviral 9y agoWhat if we could use the notion of entropy in a definition of life? Living things use energy to prevent entropy (decay?) while they are alive. On the other hand, natural, non-living processes do no such thing, and increase entropy as governed by the law of thermodynamics. We could also use criteria such as growth, reaction to stimuli, and reproduction. However, crystalline structures also grow and chemical processes may produce more of a certain molecule. All of those seek some energy minimizing equilibrium without any mitigating mechanisms.
- woodandsteel 9y agoThe problem with that definition is there are other types of systems that do that. But it certainly is an essential part of the definition.
- jwilliams 9y agoThat's true - and it's been used in a few contexts. The issue is the context. i.e. Living systems do take in energy and organize. However, if you make the box a little bigger, it's still subject to entropy. However, even drawing the box/context is useful!
- snowwrestler 9y agoYou can't beat entropy, or prevent it. All you can do is change its distribution. So, one way to look at living things is that each one is a local depression in entropy. But because you can't make something from nothing, each living thing has to broadly increase entropy in their environment, in order to decrease it locally. Thus if we envision entropy as a surface, a living thing is not a depression from a flat plane, but rather more like a hill with a steep depression in the middle. But again, since you can't have something from nothing, life can't arise from an environment of maximum entropy. In order for life to come into being, local entropy must be low enough for a hill to develop. This is where the entropic definition gets into trouble, because the local low-entropy environment around here is provided by the sun. And if you define life as any local depression of entropy, then it raises the question of whether the sun is alive. Maybe it's better to think of life as a system, not an attribute. To use an analogy, you wouldn't look at a single wave in a rapid in isolation, and wonder what it is. Without the broader context of the river, you'll never understand how the wave came to be there. If every living thing is a like a ripple in the local entropic surface, we can point to individuals, but could only really understand them if we consider the whole picture of the solar system.