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New Giant Viruses Further Blur the Definition of Life

quantamagazine.org

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Re: New Giant Viruses Further Blur the Definition of Life

#41

Post by dkersten »

cobbzilla wrote: post #23
nyc111 wrote: post #19

Earlier quoted context omitted.

>We don't consider something "alive" if its behavior doesn't change when its environment does. 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.

I think you're reading this too narrowly. The cat will respond to changes in its environment, even when sleeping. Try raising or lowering the temperature by an extreme amount while the cat is sleeping -- at some point it will awaken and seek a more comfortable place. To what extent does one need to change a virus's environment before it changes behavior? If its behavior is "fixed" by its genes and well understood, th…

So it’s more like “ability to respond to changes in the environment”.

Re: New Giant Viruses Further Blur the Definition of Life

#43

Post by jayd16 »

sebazzz wrote: post #4

I 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.

Would you consider prions to be life?

Re: New Giant Viruses Further Blur the Definition of Life

#44

Post by jamesrcole »

whatshisface wrote: post #11
sebazzz wrote: post #4

I 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.

Words are only useful insofar as they point to groups of entities that the speaker and listener agree are being pointed to. So, we should ask "what is the most useful definition of life?" It's a short word, so it's valuable real-estate. What should the definition of life be? 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.

I agree. I think a source of confusion is the following.

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.

Re: New Giant Viruses Further Blur the Definition of Life

#45

Post by jacobush »

kitd wrote: post #30
nyc111 wrote: post #22

I 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.

While 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.

Hm, you say that like it’s self evident. Don’t corporations do things alone humans couldn’t?

Re: New Giant Viruses Further Blur the Definition of Life

#48

Post by dmurray »

felipemnoa wrote: post #7
ohf wrote: post #5

Earlier quoted context omitted.

Viruses are more like robots. They don't respond to stimuli. They just, do. 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.

>>Viruses are more like robots. 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.

Except that they really do have a physical manifestation (from the article, the cylindrical tail, the polyhedral box containing the genes, the fibrils on the outside). In some way they are closer to being the USB stick containing the computer program, that can reproduce onto other USB sticks but needs a host computer to do so.

Re: New Giant Viruses Further Blur the Definition of Life

#49

Post by DelightOne »

whatshisface wrote: post #11
sebazzz wrote: post #4

I 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.

Words are only useful insofar as they point to groups of entities that the speaker and listener agree are being pointed to. So, we should ask "what is the most useful definition of life?" It's a short word, so it's valuable real-estate. What should the definition of life be? 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.

Thats "The Categories Were Made For Man, Not Man For The Categories".

Sb trying to push sb else to use a definition meets the second part of the sentence.

Re: New Giant Viruses Further Blur the Definition of Life

#50

Post by PeterisP »

Synaesthesia wrote: post #17
meri_dian wrote: post #15

Here'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 funct…

The problem with that analogy IMO is that machines can be comprehended by humans, whereas even the most primitive forms of life are more sophisticated than anything human created. Reproduction is an astonishing feat in itself - if only we could create a machine which could reproduce, but it's not so simple!

If we define reproduction as equivalent to how viruses reproduce (i.e. by repurposing machinery of cells to reproduce themselves), then we have created such machines; "built from scratch" human-made viruses exist consisting of synthetic DNA/RNA.
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