Defining Life: The Debate Over Whether Viruses Qualify

[Phrak]

but self replication is quite dangerous that would leave all strile organisms out of the definition so many crops would count as life anymore so many sterile organisms etc tehy can only grow on their own thei can't replicate.

you could get around that at least a bit by saying you apply the definition only to cell sized entitys but still i would say excluding annything what can't grow anymore is a bit difficult

Self-similar replicating system.

We're talking at odds. I'm attempting to define 'life'. You are defining 'living organisms, or living things."

What system would include crops that cannot reproduce or the product of a horse and a donkey? Individual organisms without reference to a group would not qualify, but as elements of a group, or asystem, do qualify. For instance, sexual reproduction takes two. In isolation, an individual person doesn't normally reproduce.

 

[kuzao]

I think it's an improvement over the more specific earlier one.

I do have some problems with it, though. What is "metabolize"? I think it's hard to define that without reference to life. (Feel free to disagree, with a definition!) Also, the more I think about it, the more difficulties I have with "similar". Not only is this abstract, but it also causes problems with symbiosis. What about humans and our symbiotic bacterial cultures? Worst, what about our mitochondria? How do we draw the line so those are includes but other symbiotes are not?

hmm how about replacing metabolizing with take up and process materia.

a bit difficult to answer. let me ask something in return. is a nucleus alive? he is sorounded by a wall can replicate even has sometimes dna and rna present. while the cytoplasma most offen doesn't even posses dna. so can we judge that the cell core is alive while evrything else orgaells, cytoplasma etc is dead materia?

i don't think so.

can we find a small area in a cell where we draw a circle around a partion of the space and say here inside is dna and rna. this place is alive?

i odnt think so

can we go don look at one molecule and decide if this one is living or dead materia?

no.

i think the use of the word entity is to be favored because this implies that its a unit which can consist of many parts. i guess nobody will tell you taht you are not alive but your cells are. so i would sugegst to use the defintion not for organells but only for organisms.

im not sure if we should use 'self sufficient' that would eliminate the discussion about nuclei or mitochondria but lead us to discuss only whole organisms. but then we get the problem that we have to define the environment which is enableling the self sufficiency.

 

[kuzao]

Self-similar replicating system. What system would include crops that cannot reproduce or the product of a horse and a donkey? Individual organisms without reference to a group would not qualify--but as elements of a group structure, do. For instance, sexual reproduction takes two. In isolation, an individual person doesn't normally reproduce.

im sorry but i don't understand your argument. could you elaborate?

 

[DaveC426913]

im sorry but i don't understand your argument. could you elaborate?

Many things such as mules and certain crops are unable to reproduce, yet are very much alive.

 

[Phrak]

Many things such as mules and certain crops are unable to reproduce, yet are very much alive.

Are you going to just criticize definitions or offer your own?

 

[kuzao]

Many things such as mules and certain crops are unable to reproduce, yet are very much alive.

dave do you think he/she meant that? then it would back my argument that reproductions isn't a usefull thing to inculde in a dfinition of life, or?

 

[Phrak]

im sorry but i don't understand your argument. could you elaborate?

I'm not sure I can, unless you can tell me what you want elaborated. After being unsuccessful at defining what is living vs. not-living in terms of individual organisms, I attempt to define life as more than one organism. This is what I've called a system. Living things are then part of a living system whether they can self-similarly replicate, or not.

It would be a good to define what I've been calling a 'system' in solid terms, otherwise, it's philosohpy, as you've called it. A very good point. I don't have an answer. I was hoping someone with more insight than I could identify it.

 

[kuzao]

I'm not sure I can, unless you can tell me what you want elaborated. After being unsuccessful at defining what is living vs. not-living in terms of individual organisms, I attempt to define life as more than one organism. This is what I've called a system. Living things are then part of a living system whether they can self-similarly replicate, or not.

It would be a good to define what I've been calling a 'system' in solid terms, otherwise, it's philosohpy, as you've called it. A very good point. I don't have an answer. I was hoping someone with more insight than I could identify it.

ah ok i understand :)

that would be a similar approach as in post 89, or?

there i also had problems with using species as description, i think neither species nor system is good enough. group of similar entities might be a bit better but still not good.
anyone got a good idea?

i still have some issues with replication as criteria because i think that this term complicates
the definition of the 'system' group or what ever we call it.

i will think about and write later more. now I am off to a bike tour with my wife :)

 

[DaveC426913]

dave do you think he/she meant that?

Yes.

then it would back my argument that reproductions isn't a usefull thing to inculde in a dfinition of life, or?

I wouldn't say not 'useful', I would say not unilateral.

 

[Phrak]

ah ok i understand :)

that would be a similar approach as in post 89, or?

There are two approches. You can generate a list of things like reproduction, and the ability to metabolized things, and make copies of DNA. or take this sort of list and try to identify some global attributes. The later is more abstract, with the idea that life could be more than RNA/DNA based, or include reproducing machines or software objects. You're approch is sort of in the middle.

But, let's admit it. This is all make-believe. There is no right answer; any answer is human invention. In the arena of global attributes, some want to include viruses, some don't, and both taylor their attributes accordingly.

And to throw gasoline on the fire, no one has yet brought up entropy.