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dimreepr

Planets aren't alive

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I guess a question is when, if ever, it is useful to regard the planet a living organism. Could it help motivate environmental efforts for instance, or is the risk of new age beliefs compromising scientific understanding among lay people too great?

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5 minutes ago, dimreepr said:

DA observation?

Devil's Advocate

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Ahh OK, maybe should have used my friend google...

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4 minutes ago, Prometheus said:

I guess a question is when, if ever, it is useful to regard the planet a living organism. Could it help motivate environmental efforts for instance, or is the risk of new age beliefs compromising scientific understanding among lay people too great?

How about comparing with related questions?

Is a ship alive because it carries a coat of barnacles, without the ship the barnacles would not survive.

So is a planet alive because part of it contains microorganism with no locomotive capability, but which can change its chemistry dramatically (the Earth would not have an oxygen rich atmosphere without stomatolites)

Can part of an object or a whole be alive or does it all have to be living ?

What about dead tree branches ?

Or can one livinh whole actually conmprise several living organims?

For example stomach flora, without which I would have no digestion.

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2 minutes ago, studiot said:

How about comparing with related questions?

Is a ship alive because it carries a coat of barnacles, without the ship the barnacles would not survive.

So is a planet alive because part of it contains microorganism with no locomotive capability, but which can change its chemistry dramatically (the Earth would not have an oxygen rich atmosphere without stomatolites)

Does it matter?

They can't live without the ship...

7 minutes ago, studiot said:

For example stomach flora, without which I would have no digestion.

And you can't live without the barnacles. 

Yes, I know that's an incomplete analog...

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2 minutes ago, dimreepr said:

Does it matter?

Just expanding on your TD (Tricky Dicky) statement.

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1 hour ago, studiot said:

I am looking for a definition that tells me a volcano is definitely not alive since volcanoes seem to me to satisfy both MigL's list plus your growth one as well as the ability to exist in a dormant phase where none of these happen.

There is no perfect definition of life and I have argued at various points that these are effectively a posteriori definitions which could for example exclude unknown life forms. What I provided are the most general (and hence, least specific ones) as MigLs definition included one that would exclude a sizable group of organisms.

I should also add that I think that fire might be a better example as a volcano, as I would think of it as a structure created by some external forces rather something that actually actively sustains itself via chemical processes (i.e. metabolism).

That being said, the  more specific definitions of life include the ability of certain levels of homeostasis, or define them as self sustaining system capable of Darwinian evolution to including specific structures such as cells or DNA. It is typically the inclusion of homeostasis and cellularity that provides a distinction. But as mentioned, they are all imperfect and limited by our knowledge of life on Earth.

55 minutes ago, studiot said:

For example stomach flora, without which I would have no digestion.

Another nitpick, the most microbial activity relevant to digestion is found in the gut, not the stomach. Also, you would be able to digest without bacteria, though there one could miss out on certain bacterial byproducts that are helpful to us. A better example would be animals that feed on cellulose (i.e. many herbivores), for which they typically  need eukaryotic symbionts (which typically work in association with bacterial symbionts).

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5 hours ago, CharonY said:

That being said, the  more specific definitions of life include the ability of certain levels of homeostasis, or define them as self sustaining system capable of Darwinian evolution to including specific structures such as cells or DNA. It is typically the inclusion of homeostasis and cellularity that provides a distinction. But as mentioned, they are all imperfect and limited by our knowledge of life on Earth.

 

Apologies in advance on being a little disconnected in my thinking here - emergence does that to straight thinking I find.

I've not been convinced by the typical definitions of life trotted out for students (such as myself). As you say CharonY they tend to describe features of life as we understand it here on earth.  [That in itself is somewhat incomplete.] Which is somewhat limiting. I'm also not convinced of definitions which exclude virus ( on the basis of not passing on hereditary information, and I guess, homeostasis/metabolism). It seems to me that if we find an extraterrestrial virus scientists would not just be excited but would be reconsidering those definitions.

I can imagine an electronic AI that I would be tempted to call life, that wouldn't meet any currently recognised definition. Suggests a potential problem with the definition.

The topic of emergence borders on the metaphysical but that does not seem to bother theoretical physicists at all. Though Science Philosophers seem to mostly to start with a position of the topic being junk. There is a boundary being used, especially in areas such as quantum foundations, that does not seem to robustly fit Popper. Emergence seems based on "well, we can't rule it out!", rather than any deeper foundation.

I find it hard to simply accept as tabled.

On another note, the earlier OP, seemed without stating it to be talking not just life but conscious life - which is another step entirely.

 

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24 minutes ago, druS said:

virus ( on the basis of not passing on hereditary information, and I guess, homeostasis/metabolism)

Actually the virus does that, it reproduces (or rather, makes its host reproduce) its genetic material. It is really the metabolism part as it does not have any functions to this end.

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28 minutes ago, druS said:

On another note, the earlier OP, seemed without stating it to be talking not just life but conscious life - which is another step entirely.

Yes it is worth makeing that distinction since life appears to be not one single phenomenon, but a class of phenomena.  +1

 

I have to observe that the little bit of biology I did in the early 1960s gave all of those criteria plus a few more that I forget.
But they did not require all life forms to exhibit  all of these behaviours.
They were also prepared for a fuzzy boundary between life and non life, where they placed viruses for the reasons CharonY gives.

7 minutes ago, CharonY said:

Actually the virus does that, it reproduces (or rather, makes its host reproduce) its genetic material. It is really the metabolism part as it does not have any functions to this end.

 

I don't see that we have improved on that approach since.

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13 minutes ago, studiot said:

 

I don't see that we have improved on that approach since.

I am not sure what you mean here, but one prominent view is to view viruses more as mobile genetic elements (somewhat closer to e.g. plasmids) due to the lack of metabolic activities. There is good reason to that as well, depending on what specifics you want to study. I want to restate that categorizations that we do ultimately are about usefulness as nature really does not care about boundaries that we want to impose.

Simply put, we can make a unified categorization of organisms that we unequivocally recognize as living which would exclude the likes of viruses and fire. And certainly, it would be sufficient and useful for life as we know it.

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7 minutes ago, CharonY said:

I want to restate that categorizations that we do ultimately are about usefulness as nature really does not care about boundaries that we want to impose.

With respect I think you are sidestepping that issue.

In 1960 there was already a debate about whether to classify viruses as alive or not.
At least most were prepared to agree that there is an issue and to discuss it.

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23 minutes ago, studiot said:

In 1960 there was already a debate about whether to classify viruses as alive or not.
At least most were prepared to agree that there is an issue and to discuss it.

Yes and it is still ongoing, especially among evolutionary researchers and folks with nucleic acid heavy research (though the discussion has, well evolved, as we have more information about viruses than folks in the 60s- DNA structure was only resolved barely a decade earlier). However,  for folks interested in physiology viruses are not considered to be alive. The reason being that they lack the critical elements required to have some sort of cellular physiology. The same reason why free DNA would not be considered alive for all intents and purposes (from this viewpoint).

That is what I meant with usefulness. Perhaps a bit akin to folks exclusively using classical physics when describing macroscopic systems. Does that make sense to you? Or do you mean something else that I might be missing?

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8 hours ago, studiot said:

I am looking for a definition that tells me a volcano is definitely not alive since volcanoes seem to me to satisfy both MigL's list plus your growth one as well as the ability to exist in a dormant phase where none of these happen.

That's funny, I thought about volcanoes too. Eventually settling on clouds as an even better example.

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9 hours ago, CharonY said:

However,  for folks interested in physiology viruses are not considered to be alive....................

Which nicely illustrates the one point I have been consistently making.

It is not a simple life/not-life classification; it is far more complicated than that.

10 hours ago, studiot said:
10 hours ago, druS said:

On another note, the earlier OP, seemed without stating it to be talking not just life but conscious life - which is another step entirely.

Yes it is worth makeing that distinction since life appears to be not one single phenomenon, but a class of phenomena.  +1

 

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2 hours ago, studiot said:

It is not a simple life/not-life classification; it is far more complicated than that.

This.

Lots.

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11 hours ago, taeto said:

That's funny, I thought about volcanoes too. Eventually settling on clouds as an even better example.

But it does miss the point of the OP, whilst technically a volcano and a cloud fits (as per the OP), they don't contain obvious life (clouds maybe) or the ecosystem to maintain life.

13 hours ago, druS said:

On another note, the earlier OP, seemed without stating it to be talking not just life but conscious life - which is another step entirely.

Indeed, and this thread is much more interesting and amenable whithout that sort of input.

I think life and it's ecosystem are co-dependant and inextricably linked, and so are qualitatively no different. 

 

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38 minutes ago, dimreepr said:

...they don't contain obvious life or the ecosystem to maintain life.

Yes, life should contain obvious life and its ecosystem should maintain life. But we might aim for an explanation of life which does not itself refer to the concept of life, maybe.

Similarly, the concept of "conscious" is not without trickyness. We do not think of a person who has been knocked unconscious as not being a conscious being. 

Edited by taeto

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2 minutes ago, taeto said:

Yes, life should contain obvious life and its ecosystem should maintain life. But we might aim for an explanation of life which does not itself refer to the concept of life, maybe.

Why?

Life shapes life.

 

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Just now, dimreepr said:

Why?

It doesn't seem to argue against a volcano being alive, since the ecosystem of a volcano maintains the property of having volcanoes (even if individual volcanoes eventually die, this is no different from standard lifeforms). And hence if volcanoes are lifeforms, then their ecosystem maintains life.

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11 minutes ago, taeto said:

It doesn't seem to argue against a volcano being alive, since the ecosystem of a volcano maintains the property of having volcanoes (even if individual volcanoes eventually die, this is no different from standard lifeforms). And hence if volcanoes are lifeforms, then their ecosystem maintains life.

That's just a technicality, you may as well call the floppy inflatable guy outside a car dealership alive.

A virus needs life, to be considered alive.

Edited by dimreepr

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58 minutes ago, dimreepr said:

I think life and it's ecosystem are co-dependant and inextricably linked, and so are qualitatively no different. 

Insofar as an ecosystem, generally interpreted, means the totality of present lifeforms that interact with each other, and lifeforms are the perceived individual components of any ecosystem, this kind of thinking is not far-fetched. Still they are qualitatively different. Within an ecosystem, the different lifeforms have different roles in processing the chemical composition of the system. We can refer to the function of each different live object and abstract the totality of objects that have essentially the same function into a single species of life form. The converse is not quite true, at least not in the way that we ordinarily use language. Even a system composed of various essentially similar different ecosystems is not identified as a single life form, especially since by definition, different ecosystems do not interact. Lifeforms do interact.

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Thinking about definitions: There are actually no lines or demarcations between things but we mentally construct them for purposes of communicating and specificity; definitions are, ultimately, purely arbitrary and consensual  ideas for our discussive convenience.

Edited by StringJunky

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4 minutes ago, taeto said:

different ecosystems do not interact. Lifeforms do interact.

My ecosystem interacts with a bee's ecosytem.

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1 minute ago, dimreepr said:

My ecosystem interacts with a bee's ecosytem.

It is because it is the same ecosystem.

EDIT: assuming, for the sake of argument, that you are a live person.

Edited by taeto

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