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Author Topic:   What is Life?
Dr Adequate
Member (Idle past 289 days)
Posts: 16112
Joined: 07-20-2006


(1)
Message 10 of 268 (581080)
09-13-2010 1:28 PM
Reply to: Message 1 by mosassam
09-02-2010 10:00 PM


The dominant issue of the EvC debate concerns Life but there seems to be no consensus on what Life actually is.

That's because this isn't really a scientific question.

We begin with a naive idea of life where some things are definitely alive (me, a goldfish, a rosebush) and some things definitely aren't (rocks, bicycles, the Moon). When we study this matter more closely, we find that there's a number of properties common to the first set and absent from the second. "Aha," we say, "so that's what life means."

Now the problem comes when we observe or imagine something which has some of these properties but not others. Is that life?

And this, as I say, is not a scientific question --- it's a question about how we want to use language, which is a matter of social convention not to be solved by scientific inquiry. Fortunately, we don't have to solve it. We can just discuss what properties objects have without ever deciding which of those properties add up to something that we'd like to call "life".

However, the word "life" is convenient: thhat's what social conventions are for. I would suggest that we should define it in the way that is most convenient for whatever particular situation we find ourselves in.

In the context of these boards, the convenient place is that point at which the (short) answer to any given question is "evolution". That is, the significant features defining "life" should be reproduction with variation.


This message is a reply to:
 Message 1 by mosassam, posted 09-02-2010 10:00 PM mosassam has replied

Replies to this message:
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Dr Adequate
Member (Idle past 289 days)
Posts: 16112
Joined: 07-20-2006


(1)
Message 56 of 268 (592950)
11-23-2010 12:27 AM
Reply to: Message 43 by AlphaOmegakid
11-22-2010 6:34 PM


Re: Sad Sad Sad
This thread is a sad commentary of the intellect of those in this forum. Three pages of semantic garbage and not one attempt at a scientific definition.

This is, of course, not true, as anyone reading this thread can see.

Well that's not science it is religious equivocation.

No, that's a falsehood that you made up in your head so that you could have something to whine about.

By the way, this is the second time today I've had occasion to wonder why the more religion-ridden a person gets, the more likely he is to use "religious" as a term of abuse. Is it because deep down you know that religion is stupid, or is there some other reason? I'm fascinated.

As I pointed out to the other bozo, if I wish to condemn a thing I wouldn't call it "scientific". That would be strangely inconsistent.

Here is probably the best definition I've seen.

So ... viruses are not alive?

And, apparently, God is dead. Nietzsche would be thrilled.

You note, by the way, that he makes evolution part of the definition of life?

The second pillar of life is IMPROVISATION. Because a living system will inevitably be a small fraction of the larger universe in which it lives, it will not be able to control all the changes and vicissitudes of its environment, so it must have some way to change its program [...] In our current living systems, such changes can be achieved by a process of mutation plus selection that allows programs to be optimized for new environmental challenges that are to be faced.

So if the standard creationist denial of optimization by mutation and selection was correct, then according to your chosen definition we would have to say that nothing was alive.

Now, the only reason the evos won't attempt to define life ...

You just quoted one doing so. Do try to lie less often.

Edited by Dr Adequate, : No reason given.


This message is a reply to:
 Message 43 by AlphaOmegakid, posted 11-22-2010 6:34 PM AlphaOmegakid has replied

Replies to this message:
 Message 58 by AlphaOmegakid, posted 11-23-2010 8:54 AM Dr Adequate has replied

  
Dr Adequate
Member (Idle past 289 days)
Posts: 16112
Joined: 07-20-2006


Message 68 of 268 (592975)
11-23-2010 10:38 AM
Reply to: Message 58 by AlphaOmegakid
11-23-2010 8:54 AM


Re: Sad Sad Sad
AOKid writes:

Well it is true. Read the three pages. Not one scientific definition of life was provided the OP writer until I provided one. Sad, sad, sad. If you think there was one prior then enlighten us all on it.

AZPaul3, post #6 writes:

Everyones own pet definition can be shown to harbor inconsistencies, anomalies, omissions and absurdities.

But since you asked:

Life is complex chemistry in continuous action.

frako, post #9 writes:

im guessin the simplest and closest exsplenation for a sientist would be somthing is alive if it reproduces itself naturaly in some way

Dr Adequate, post #10 writes:

In the context of these boards, the convenient place is that point at which the (short) answer to any given question is "evolution". That is, the significant features defining "life" should be reproduction with variation.

jar, message #25 writes:

It means that the thing seems to be something that reproduces by one of many different methods, capable of movement, that takes in some form of energy and expels some form of waste at least during part of its life cycle and that at some point can be said to be not alive.

Parasomnium, post #30 writes:

I believe Richard Dawkins said somewhere that life is molecular information technology, and I think he was pretty much on the mark there.

Parasomnium, post #41 writes:

Ever since Darwin we know quite well what the driving force behind the increasing complexity of life on earth is: it's Darwinian evolution. This suggests another interesting way of defining life, for which I'll quote Gerald Joyce (look under the heading "Proposed", a bit further down):

"Life is a self-sustained chemical system capable of undergoing Darwinian evolution."

I guess now you're going to thank me, right?

... no?

AOKid writes:

No, the only falsehood in this thread is that life is undefinable, and that is religious equivocation.

Perhaps you could quote someone saying that "life is undefinable". Or perhaps you can't, since the only use of the word "undefinable" in this thread is in your post to which I am currently replying.

And science has defined life in one way shape or form since the beginning of the use of the term "biology".

In several ways, shapes, and forms.

So ... viruses are not alive?

That seems to be the scientific concensus.

"Consensus" is too strong a term. According to Nobel Laureate David Baltimore, for example: "There’s a running debate about whether viruses are alive or dead". It doesn't sound like he agrees with you that there's a consensus, but maybe you know better than him, what with you being such a non-eminent non-scientist and all.

More irrational thought processes. This is a category error.

No, that's what we scientific types call a "joke". You may have heard the term. Perhaps when you have a minute free you could look it up.

Nope, he does define IMPROVISATION.

And he says that in "In our current living systems, such changes can be achieved by a process of mutation plus selection that allows programs to be optimized". Which is a description of adaptive evolution by Darwinian processes.

In it he mentions mutation and natural selection, but this is just a portion of evolution.

And a portion of evolution is evolution, just as a portion of salami is salami.

Do you really mean to pretend that the optimization of organisms through mutation and selection isn't evolution, or are you just typing words at random?

Well first off your premise is false. No major creationist organization I know of denies that mutations and natural selection happens in living organisms. AIG, CMI, ICR, even Hovind agrees with mutation and natural selection happening in living creatures.

But creationists do often deny that they operate as an optimizing force.

Take this guy, for example:

Mutation, which acts on the complex information in the DNA in a random and unconscious manner, harms the DNA, and therefore harms the organism bearing the DNA. At best, it may have no effect at all. However, mutations can never add any new information to DNA, and do not make any kind of improvement in the organism. Not a single instance of this has ever been observed. [...] They modify what preexists, but they do so in disorder, no matter how� As soon as some disorder, even slight, appears in an organized being, sickness, then death follow.

Perhaps you should email this guy and tell him that he is a "rather deceitful strawman" constructed by me. He will be surprised, as will his parents.

So you have constructed a rather decietful strawman argument. Why do you do that?

Says the man who just read and quoted me saying that creationists often deny "optimization by mutation and selection", and then pretended that I'd said that they deny mutation and selection.

Mind you don't choke to death on your own hypocrisy, now.

You inability to read and comprehend does not constitute me lying. The evos in this thread have purposely mislead the public that life is not definable. The reason those evos do that is they need the wiggle room of equivocation when it comes to the origin of life.

I didn't say "all evos don't define life." I said that "the only reason the evos won't attempt to define life ..." .

And you did not say "the only reason the evos on this thread won't attempt to define life ..."

If you wished only to lie about evolutionists on this thread and not evolutionists in general, you should have said so. There was nothing to indicate which lie you were trying to tell; and as both are equally false it was impossible to discover from context.

The evos in this thread have purposely mislead the public that life is not definable ... All of these athors do provide definitions of life contrary to what the equivocators in this forum are doing.

See, now there your lie is clear and explicit. Well done!

But perhaps your posts would be even better if you would tell the truth. It's really quite painless, you should try it.

Edited by Dr Adequate, : No reason given.

Edited by Dr Adequate, : No reason given.

Edited by Dr Adequate, : No reason given.


This message is a reply to:
 Message 58 by AlphaOmegakid, posted 11-23-2010 8:54 AM AlphaOmegakid has replied

Replies to this message:
 Message 107 by AlphaOmegakid, posted 11-30-2010 8:41 AM Dr Adequate has replied

  
Dr Adequate
Member (Idle past 289 days)
Posts: 16112
Joined: 07-20-2006


Message 71 of 268 (592982)
11-23-2010 12:12 PM


Life?
On this thread I proposed the following definition:

Life is a collection of chemicals that, given the right environmental conditions, can promote their own synthesis through surface catalysis.

Discuss.


Replies to this message:
 Message 73 by Straggler, posted 11-23-2010 12:20 PM Dr Adequate has replied
 Message 78 by crashfrog, posted 11-23-2010 12:54 PM Dr Adequate has replied
 Message 86 by Stephen Push, posted 11-23-2010 10:26 PM Dr Adequate has replied

  
Dr Adequate
Member (Idle past 289 days)
Posts: 16112
Joined: 07-20-2006


Message 72 of 268 (592983)
11-23-2010 12:19 PM
Reply to: Message 43 by AlphaOmegakid
11-22-2010 6:34 PM


Viruses Again
Yes science defines life. There are definitions in every science textbook printed. Biology is the study of life and life is definable.

So, just to clarify.

* Biology is the study of life.
* Viruses are (per your favored definition) not life.

So, tell me. If someone spends his whole scientific career studying viruses ... does that mean that he is not a biologist?

Edited by Dr Adequate, : No reason given.


This message is a reply to:
 Message 43 by AlphaOmegakid, posted 11-22-2010 6:34 PM AlphaOmegakid has taken no action

Replies to this message:
 Message 89 by Dr Jack, posted 11-24-2010 7:53 AM Dr Adequate has replied

  
Dr Adequate
Member (Idle past 289 days)
Posts: 16112
Joined: 07-20-2006


Message 75 of 268 (592986)
11-23-2010 12:38 PM
Reply to: Message 63 by AlphaOmegakid
11-23-2010 9:52 AM


Category Errors
Yes, he is an evo. And so are most of the authors of biology textbooks. But these evos ARE willing to define life.

They do not fit the category of those evos that "won't attempt to define life." Do you know what a category error is?

So when you said "the evos won't attempt to define life", what you meant was: "the evos who won't attempt to define life [a set which may be completely empty] won't attempt to define life."

I see. Very well then.

Creationists are child molesters.

Anyone who takes this as a libel on creationists is committing a fallacy, since (as we now know) this remark applies only to those creationists who are child molesters, and not to those who aren't. Hence if I go around saying "creationists are child molesters" I am speaking the truth as a matter of logical necessity, and anyone who disagrees with me by producing an counterexample of a creationist who is not a child molester is perpetrating a "category error".

Indeed, I would be speaking the truth even if not one single creationist is a child molester, since the statement that all creationists who are child molesters are child molesters does not in any way imply that the set of creationists who are child molesters is non-empty.

Clearly creationists have much to teach us about logic ... like how not to do it.

Edited by Dr Adequate, : No reason given.


This message is a reply to:
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Dr Adequate
Member (Idle past 289 days)
Posts: 16112
Joined: 07-20-2006


Message 76 of 268 (592987)
11-23-2010 12:39 PM
Reply to: Message 73 by Straggler
11-23-2010 12:20 PM


Re: Life?
Is a virus a form of life by this definition?

Yes.


This message is a reply to:
 Message 73 by Straggler, posted 11-23-2010 12:20 PM Straggler has replied

Replies to this message:
 Message 77 by Straggler, posted 11-23-2010 12:43 PM Dr Adequate has replied

  
Dr Adequate
Member (Idle past 289 days)
Posts: 16112
Joined: 07-20-2006


Message 79 of 268 (592997)
11-23-2010 1:02 PM
Reply to: Message 77 by Straggler
11-23-2010 12:43 PM


Re: Life?
Is a strand of RNA a form of life by this definition?

I guess it would include RNA species, sure. But not prions, before you ask.

I think I see where you're going, and I foresee difficulties with my proposed definition. I may have ponder this more carefully.


This message is a reply to:
 Message 77 by Straggler, posted 11-23-2010 12:43 PM Straggler has replied

Replies to this message:
 Message 80 by Straggler, posted 11-23-2010 1:07 PM Dr Adequate has replied

  
Dr Adequate
Member (Idle past 289 days)
Posts: 16112
Joined: 07-20-2006


Message 81 of 268 (593000)
11-23-2010 1:16 PM
Reply to: Message 78 by crashfrog
11-23-2010 12:54 PM


Re: Life?
Interesting and potentially broad. To me it makes sense to distinguish between collections of chemicals that both promote their own synthesis and do redox chemistry ...

That sounds like a good way to capture certain concepts of life. I like it.

I wonder, though, whether it might exclude certain kinds of "life, but not as we know it". I am not even remotely good at chemistry, but it seems that acid-base reactions (for example) are not redox reactions. Now, can we imagine something which we would like to call "life" having what we would like to call a "metabolism" which use that sort of chemistry instead? Or is there some chemical reason why this is inconceivable?

I think you have to have a metabolism to be alive. Mere self-replication, in my opinion, doesn't allow for the expansive diversity and complexity that characterizes living things. The crucial step, to me, is metabolism.

Well, this is exactly why there's a gray area. My gut tells me that viruses should be categorized as life, and in the end our guts are all we have to go on --- there's no objectively correct definition.

Of course, by my definition battery-powered machines could be alive. The minute Roombas start assembling other Roombas, I guess they're alive.

What if this doesn't involve redox chemistry?


This message is a reply to:
 Message 78 by crashfrog, posted 11-23-2010 12:54 PM crashfrog has replied

Replies to this message:
 Message 83 by crashfrog, posted 11-23-2010 2:48 PM Dr Adequate has replied

  
Dr Adequate
Member (Idle past 289 days)
Posts: 16112
Joined: 07-20-2006


Message 82 of 268 (593001)
11-23-2010 1:29 PM
Reply to: Message 80 by Straggler
11-23-2010 1:07 PM


Re: Life?
But if it made you think more about the definition in question then I guess that is a good thing.

Well I think the problem might be that I haven't shown how to draw a line between the chemicals in question and the "right environment" that I mentioned, and this might become problematic if we pushed it far enough.

I could wish my knowledge of chemistry was more extensive.


This message is a reply to:
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Dr Adequate
Member (Idle past 289 days)
Posts: 16112
Joined: 07-20-2006


Message 84 of 268 (593013)
11-23-2010 3:00 PM
Reply to: Message 83 by crashfrog
11-23-2010 2:48 PM


Re: Life?
I don't know if you can "make a living" on acid-base chemistry, because I don't think there's a high enough change in free energy to exploit.

But if they did, you'd want to call them "life", wouldn't you?

Well, I mentioned batteries because batteries operate by redox.

You see the things I don't know?

I do know that if they were battery-powered, the laws of thermodynamics would eventually stop your replication process. You'd want them solar-powered or something.


This message is a reply to:
 Message 83 by crashfrog, posted 11-23-2010 2:48 PM crashfrog has replied

Replies to this message:
 Message 85 by crashfrog, posted 11-23-2010 3:58 PM Dr Adequate has taken no action

  
Dr Adequate
Member (Idle past 289 days)
Posts: 16112
Joined: 07-20-2006


Message 87 of 268 (593056)
11-23-2010 10:42 PM
Reply to: Message 86 by Stephen Push
11-23-2010 10:26 PM


Re: Life?
Are prions life according to that definition?

No. The infectious prions make normal prions change their shape to that of infectious prions. But they do not catalyze the synthesis of infectious prions.


This message is a reply to:
 Message 86 by Stephen Push, posted 11-23-2010 10:26 PM Stephen Push has replied

Replies to this message:
 Message 88 by Stephen Push, posted 11-24-2010 7:31 AM Dr Adequate has replied

  
Dr Adequate
Member (Idle past 289 days)
Posts: 16112
Joined: 07-20-2006


Message 91 of 268 (593101)
11-24-2010 10:54 AM
Reply to: Message 90 by Jon
11-24-2010 10:09 AM


Re: It is What we Make It
The importance of the differences between life and non-life is the same as the importance of the differences between a rock and a mountain. And where does a rock begin and a mountain end?

A good example --- because in geology there is no formal definition telling us when we're looking at a mountain and when we're looking at a big hill.

And a bad example --- because there we're dealing with a continuous quantitative scale (height). The case is different with life. A bacterium doesn't just have more of some quality than (for example) a grain of sand. It has different qualities.


This message is a reply to:
 Message 90 by Jon, posted 11-24-2010 10:09 AM Jon has replied

Replies to this message:
 Message 96 by Jon, posted 11-25-2010 2:33 AM Dr Adequate has replied

  
Dr Adequate
Member (Idle past 289 days)
Posts: 16112
Joined: 07-20-2006


Message 92 of 268 (593102)
11-24-2010 10:57 AM
Reply to: Message 89 by Dr Jack
11-24-2010 7:53 AM


Re: Viruses Again
No, because the study of viruses is necessarily linked to the study of the living host of viruses. You cannot understand a virus without also understanding certain aspects of their hosts.

What if all he studies is their taxonomy through molecular phylogeny? Or the self-assembly of their protein coats? (I suppose in the second case there is a case that he's just a biochemist. But in the first case, not so much.)


This message is a reply to:
 Message 89 by Dr Jack, posted 11-24-2010 7:53 AM Dr Jack has replied

Replies to this message:
 Message 98 by Dr Jack, posted 11-25-2010 11:10 AM Dr Adequate has taken no action

  
Dr Adequate
Member (Idle past 289 days)
Posts: 16112
Joined: 07-20-2006


Message 93 of 268 (593103)
11-24-2010 11:01 AM
Reply to: Message 88 by Stephen Push
11-24-2010 7:31 AM


Re: Life?
The prevailing theory of prion replication involves "autocatalytic protein misfolding." Why wouldn't that fall within your definition of "life"?

Because it doesn't say "autocatalytic protein mis-synthesis".

Recent research also shows that, although they lack nucleic acids, prions undergo Darwinian evolution, including mutation and natural selection.

Interesting, I'd like to look at that research, if you have a link. Thanks.

But my feeling is that they aren't really performing reproduction as such.

Question: is it possible to come up with a simple definition which includes prions but excludes the growth of crystals in solution?


This message is a reply to:
 Message 88 by Stephen Push, posted 11-24-2010 7:31 AM Stephen Push has replied

Replies to this message:
 Message 95 by Stephen Push, posted 11-24-2010 9:51 PM Dr Adequate has taken no action

  
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