New Giant Viruses Further Blur the Definition of Life
quantamagazine.org
quantamagazine.org
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.
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.
Human society is complex, but it would not normally be considered biology.
I guess the definition really is pretty fuzzy and arbitrary. It's "obvious" why a bunny is biology and a car or company is not, but it's not quite so obvious why a virus or an android isn't.
Heck, xenobiology seems to be inherently problematic because alien life would defy all classification. Imagine the "xenomorph" from the Alien universe. Would that be considered a reptile? Is it even a vertebrate? What animal rights legislation would apply to it if any? Would a "grey" count as a person? We like to justify these laws with biological categories but what do we do when faced with situations where the categories break down?
EDIT: Is an artificial, viable sheep-human hybrid an animal or a human?
Change them to suit the world as we understand it.
The reality is that classifications as strict rules are a fantasy we choose to believe in, but at the end of the day, classifications are descriptions, and so we have to mutate them to help us describe things as best we can.
The reality is we work to the level of detail and accuracy we need. Rigidity in labels and classification is probably a sign of a lack of understanding, because almost everything ends up being broken down more at some point, and exceptions are found that break the rules.
I'm almost sure there are anthropologists who share the same view :)
The study of multi-organism systems: populations, ecosystems and the like is commonly associated with Biology, or a branch (Ecology). They will go as far as "biosphere", in an attempt to study the entire planet.
That biology can be called 'the study of complex things' does not imply that all complex things fall under biology. It's silly to even have to point this out.
Doesn't it? How could it not? Can you give me another example from common parlance of the form "X is the study of Y" where many Y do not fall under X?
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.
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.
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!
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.
The definition of "life" comes down to splitting hairs. We don't consider something "alive" if its behavior doesn't change when its environment does.
The entire process of injecting their RNA is simply a chemical reaction to being attached to a receptor.
Basically, they just drift along until they hit a bacteria with the right receptor, then inject their genetic material and the empty hull is either discarded or simply continues to hang onto the cell.
The outer hull of the phage doesn't do a lot.
A virus is just a computer program that needs a Von Neumann machine (CPU) to run on. Following this analogy we could define alive by saying that the combination of a program and a Von Neumann machine makes the entity alive.
[0]: Let's not argue about whether it makes sense to say that abstract concepts also have a physical manifestation. Programs are concrete expressions encoded on a physical medium (whether using magnets, electrical charges or even the position of mechanical switches).
for a bacteria the most common response to environmental change is to die
I think this is too vague. A cat may continue to sleep without responding to changes in its environment but may respond to an internal stimulus (hunger) and get up and go. So response or lack of response to the environment may not be a good criterion to define life.
Anyway, the term "life" is poorly and inconsistently defined and really only means "what we generally think of as life".
We want to exclude viruses because they are too mechanical. There's no magic to them. That's the way it appeared before we started finding all these giant viruses anyways.
But the presence of a cell wall is a pretty significant feature nonetheless.
It's similar to how it's difficult to argue whether a data format is a programming language (Turing completeness is an obvious but unnecessary and insufficient distinction). "Declarative programming languages" muddy the waters but most people would agree that a JPEG image is just data whereas a PHP script is a program.
It's easy to get wrapped up into discussions about words, but don't forget that the things they point to is what's really interesting.
Everyone has built up, over their lifetime, an implicit mental notion of "life", which is based upon the sorts of characteristics of things they classify as being alive. Many (I'd say most) people think this mental notion is some objective category that exists external to their mind, some thing that has a kind of essence that is shared by all the instances of life. They see the task of defining life as defining the essence of this category, and see there being an objective question as to whether something (e.g. a kind of virus) fits this category.
But this is to confuse a mental construct with what is out there. There are the objective properties of things like different types of viruses, different types of bacteria, of different types of mammals, and of all other natural phenomena. You can talk about what the similarities and differences are between the objective properties of a type of virus and a type of bacteria, for example, and there are simpler kinds of phenomena vs more complex ones, but there's no actual "life" category out there, separate from our mental constructs, to be objectively defined.
Even chemicals "evolve"
Sb trying to push sb else to use a definition meets the second part of the sentence.
This is post-modernism in thin disguise.
Certain categorizations can be more valuable (practical, useful, just, etc) than others, in which case it's reasonable to rally for their use over other, less valueable, categorizations.
To the second part: To one practical is to the other unpractical. To one just is to another unjust.
To push certain categories over others just says to me you want them to be in your frame(practical, useful for you I guess?).
And to not give an argument on the usefulness is to hide intention. But I'm not too firm on that yet.
It's most assuredly post-modernist because it implicitly assumes that all categories are equal in value (i.e.: that no category is better than another), and that the decision is at it's core a power-struggle (i.e.: oppressive to the loser).
This is, again, a tired and fruitless approach.
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.
https://www.cliffsnotes.com/cliffsnotes/subjects/sciences/wh...
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.)
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.
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?
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.
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.
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.
It's a bit slower than we regularly imagine computer-based AI to be, of course :)
I'm pretty confident there are not now, and never have been, any corporations with this characteristic.
I agree with your comment. This is how I think about corporations too. But I'd like to mention something about the name "Artificial Intelligence". I think that Artificial Intelligence is not artificial and it is not intelligent. I define AI as the ability of an organism to make right decisions to perpetuate its existence. Not only this is not artificial it is a widespread natural process. I also use it as the definition of life. An organism that can make the right definitions to perpetuate its existence is said to be alive.
Or maybe, more generally, the ability to make decisions.
If you "execute" the program manually, you may still not understand Chinese, but the program still does. The room, including you and the program, is functionally a single entity that speaks Chinese. The human is an implementation detail as much as the grey matter is an implementation detail in a Chinese speaking human.
Searle's argument that the machine does not actually possess "understanding" is simply special pleading. Unless he can define "understanding" in a meaningful way, the difference between an "understanding" entity and a "simulating" entity is non-existent.
These arguments all boil down to unscientific armchair philosophy. I have no idea why people seem to accept them as meaningful other than that the people who came up with them or wrote about them are otherwise highly regarded -- but that's literally an argument from authority.
Do I need to define "living"? I may just list some living organisms everyone agrees that they are living organisms such as animals, plants, and bacteria. Their common element to me is not that they have a visible body but their ability to make intelligent decisions to further their existence. So to me, to have a biological body is not a requirement to be alive. The only requirement is the ability to make intelligent decisions to perpetuate its existence as an organism. What I am saying is that life start as the result of an agreement between entities. Human body is the result of an agreement between the egg and the sperm. A legal entity starts as a legal entity. Why do you think corporations cannot be considered live organisms?
> Their common element to me is...
Stating what you mean when you're talk of 'living', as you're doing here, is giving your definition of it.
> Why do you think corporations cannot be considered live organisms?
Did I say anything to that effect? Not in the comment you're replying to.
In another comment on this post I said that a notion of 'living' is a mental construct, not an objective phenomenon outside of ourselves.
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.
Reproduction is an astonishing feat in itself - if only we could create a machine which could reproduce, but it's not so simple!
I like this definition, because it implies some kind of "trying" -- life must "try" to keep some balance that continues its existence.
(a) Viruses (and certain bacteria) confound this approach because they can indefinitely continue (and even evolve) their existence without actively maintaining or improving any kind of this "balance"; they rely on their host to provide the balance, or at least some critical parts of it (if by definition, they cannot exist outside a host).
(b) Does this make them life? Unclear, maybe.
(c) Could such an organism evolve to no longer depend on a host? Yes, conceivable.
(d) Would this organism that maintains homeostasis on its own be considered life? I would venture to say yes.
So at what point during the evolution from (a) to (d) did this organism become "life"? It seems like it is just semantics at that point. Pick your criterion, call it life.
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.
Fascinating if true.
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.
Of course, most of those viruses would probably just be rendered inert, printing a lot of segfaults into the kernel console.
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?