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Author Topic:   What is Life?
Blue Jay
Member (Idle past 1936 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


Message 38 of 268 (587235)
10-17-2010 9:36 PM
Reply to: Message 33 by mosassam
10-17-2010 4:37 PM


Hi, Mosassam.

Welcome to EvC!

I think the point everyone is trying to get across to you is that defining "life" really is only a semantic issue, and nothing more.

Generally, biologists define "life" with an arbitrary set of criteria that are usually formulated such that the set of things the particular biologist wants to consider "life" get included, while everything else gets excluded. Later biologists may latch on to these definitions and defend them dogmatically, but that’s neither here nor there as far as I’m considered.

We currently have no evidence for the existence of a sort of essence or property that distinguishes what we call "life" from what we don't call "life." Currently, we can only describe life based on a few superficial characteristics like “self-replication” or “growth,” none of which has been found to be unique to whatever group of things we define as “life.”

So, it seems that “life” is just the co-occurrence of multiple distinct factors that can be found in isolation or in partial combinations outside of what we commonly call “life.” This does not seem to offer much opportunity for “life” to be a distinct property or essence.

But, this is just more semantic nonsense, I suppose.


-Bluejay (a.k.a. Mantis, Thylacosmilus)

Darwin loves you.


This message is a reply to:
 Message 33 by mosassam, posted 10-17-2010 4:37 PM mosassam has taken no action

  
Blue Jay
Member (Idle past 1936 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


Message 39 of 268 (587239)
10-17-2010 10:25 PM
Reply to: Message 37 by Straggler
10-17-2010 5:59 PM


Re: Clumsy label
Hi, Straggler.

Straggler writes:

Are viruses a form of life according to biologists or not?

I have never been very clear on this.

If you are ever very clear on this, I would take it as evidence that you are out of touch with reality.

But, since the people who study viruses are generally thought of as biologists, and since the study of viruses is parallel to the study of "real" living things in virtually every way, I think you're safe categorizing biologists as de facto proponents of viruses as life-forms, although they may or may not formally argue one way or the other until they're blue in the face.


-Bluejay (a.k.a. Mantis, Thylacosmilus)

Darwin loves you.


This message is a reply to:
 Message 37 by Straggler, posted 10-17-2010 5:59 PM Straggler has taken no action

  
Blue Jay
Member (Idle past 1936 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


(1)
Message 53 of 268 (592945)
11-22-2010 10:30 PM
Reply to: Message 43 by AlphaOmegakid
11-22-2010 6:34 PM


Re: Sad Sad Sad
Hi, AOk.

AlphaOmegakid writes:

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

Which means... what, exactly?

The fact remains that many things that do not fit the definition of "life" are still more similar to things that are defined as "life" than other things that are not defined as "life" (e.g. a virus is more like "life" than it is like a grain of sand).

What do you do with things that match five of the seven pillars, or four, or six?

Assigning things to discreet categories doesn't make the gradients between them magically disappear.

Edited by Bluejay, : virus example and some cosmetic changes.


-Bluejay (a.k.a. Mantis, Thylacosmilus)

Darwin loves you.


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 60 by AlphaOmegakid, posted 11-23-2010 9:19 AM Blue Jay has replied

  
Blue Jay
Member (Idle past 1936 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


Message 94 of 268 (593123)
11-24-2010 1:04 PM
Reply to: Message 60 by AlphaOmegakid
11-23-2010 9:19 AM


Re: Sad Sad Sad
Hi, AOk.

AlphaOmegakid writes:

I hire employess. A requirement in certain positions is a high school doploma or GED. Completing 12 grades with no diploma is not necessarily any better than completing 10 grades with no diploma. But a diploma does have meaning.

First, you can't really complete 12 grades without getting a diploma: if you didn't get a diploma, it means you didn't complete at least 1 grade.

Second, if people who've completed 12 grades are not necessarily more capable of handling the job than people who've only completed 10 grades, then there is no meaning to completing 12 grades beyond that arbitrarily assigned to it by the arbiter. That is, the diploma holds meaning only because you, the employer (or the law that you're abiding by), say it does.

Likewise, in defining life, we're not just looking for something to which we can assign meaning: we're looking for something that has meaning beyond what we assign to it. Clearly, the diploma has no such meaning in your example, so it is not a good analogy for things that actually hold meaning.

-----

AlphaOmegakid writes:

A brick is a buiding block of a brick house. But it is far away from the definition of a brick house. You can organize bricks and make a fireplace with bricks and mortar. This is closer to the definition of a brick house, but it still does not meet the definition of a brick house.

At what point does a pile of bricks become a brick house?
When the last brick is put into place?
When the mortar dries?
When the electrician approves the wiring and the water main is turned on?

If you were showing off your 75%-completed house, and you said to your friends, "look at my new house!"---would you be justified in using the term "house"? I wouldn't make a fuss about it.

And then, when the brick house is completed, how many bricks have to fall out of the west wall before we have to stop calling it a brick house?
If a tornado took a chunk out of the garage, would you have to revert to calling it an "organized pile of bricks"?

"Brick house" is not all that clearly defined in relation to "pile of bricks," so this is yet another example of a pair of terms that are only distinguished insomuch as we choose to distinguish them.

-----

AlphaOmegakid writes:

Bluejay writes:

What do you do with things that match five of the seven pillars, or four, or six?

You give them a special scientific name. Something like "virus". And you recognize that they meet 5 of the 7 criteria, but they do not meet the full criteria.

And then what? Treat them like "not life"? Consider them the equivalent of rocks and sand? Or acknowledge that they fit somewhere between rocks and "life," and thereby reject the idiot classification that has us claiming that "life" is discreetly and distinctly different from "not life"?

Actually, virologists treat viruses just as if they were "life." They study their behavior as if they were "life." They study their physiology and genetics as if they were "life." They study their evolution as if they were "life." In fact, biologists consider people who study viruses to be a type of biologist.

This raises the question of why we defined "life" to exclude viruses in the first place. Clearly, that definition hasn't had much effect on how we treat them; also clearly, that definition doesn't prevent them from being more like "life" than like other things that are "not life."

This is what a biologist means when they argue about the definition of "life" being unclear: not that it's impossible to cobble some things together into a workable definition, but that the definition doesn't really hold much meaning in terms of how things function, behave or evolve.


-Bluejay (a.k.a. Mantis, Thylacosmilus)

Darwin loves you.


This message is a reply to:
 Message 60 by AlphaOmegakid, posted 11-23-2010 9:19 AM AlphaOmegakid has replied

Replies to this message:
 Message 102 by AlphaOmegakid, posted 11-29-2010 9:44 AM Blue Jay has replied

  
Blue Jay
Member (Idle past 1936 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


Message 179 of 268 (595159)
12-07-2010 12:14 AM
Reply to: Message 102 by AlphaOmegakid
11-29-2010 9:44 AM


Re: Sad Sad Sad
Hi, AOk.

AlphaOmegakid writes:

...the diploma holds meaning in a variety of contexts outside of hiring.

But the context of your analogy was hiring, so none of these other meanings are relevant to your analogy.

-----

AlphaOmegakid writes:

Bluejay writes:

...in defining life, we're not just looking for something to which we can assign meaning: we're looking for something that has meaning beyond what we assign to it.

Baloney! We ARE looking for something we can assign meaning. The living organisms are distinctly different from those which are non-living. Including viruses.

Okay, you obviously didn't understand what I wrote. I know this because the example you provided is not an example of the thing you were trying to defend, but an example of the opposite option.

Assigned meaning is meaning that doesn't exist until we define it to exist. This is opposed to real meaning, which is meaning that exists independent of a definition that we assign to it. Anytime you define something based on a series of attributes that are not always correlated with each other, the meaning is assigned, and not real.

-----

AlphaOmegakid writes:

No [viruses] are not equivalent to rocks and sand. We know this, because rocks and sand have definitions. And viruses don't meet those definitions.

Would you say viruses are more similar to things in the category "life" or to things in the category "rocks, sand and other minerals."


-Bluejay (a.k.a. Mantis, Thylacosmilus)

Darwin loves you.


This message is a reply to:
 Message 102 by AlphaOmegakid, posted 11-29-2010 9:44 AM AlphaOmegakid has taken no action

  
Blue Jay
Member (Idle past 1936 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


(1)
Message 206 of 268 (598322)
12-30-2010 10:27 AM
Reply to: Message 202 by Philip Johnson
12-30-2010 9:18 AM


Re: What is the simplest life form?
Hi, Philip.

Welcome to EvC!

First, you might be interested in learning the formatting codes that we use here:

If you type [qs]This is a quote box[/qs], you get this:

This is a quote box

You can also put [qs=Name of quoted person] instead of the [qs] to get this:

Name of quoted person writes:

This is a quote box

That ought to help you out some.

There's also a "peek" button at the bottom right of each message. You can click on that to see what codes were used for different formatting styles.

-----

Philip Johnson writes:

If it is just as likely that things become more complex as it is that things become less complex, then there is no directionality.

However, I suspect that we all believe that there is in fact directionality.

You suspect wrong.

I agree with Jar that "complexity" is a nearly useless word from a scientific standpoint, but I'll use it here just for the sake of argument.

Evolution doesn't take place on a gradient of complexity from "simple" to "complex": evolution takes place across a large number of gradients and other axes of variation, such as "body size, small to large," "finger length, short to long," "digestive system compartmentalization," etc. The interactions of all these gradients make a wide diversity of organisms that are not very easy to arrange on a basic gradient from "simple" to "complex.

Some lineages indeed show a trend toward increasing complexity. But, equally many show a trend toward decreasing complexity. And, by far the majority of lineages show a combination of both.

For example, you could argue that the brain has become more complex in the lineage that went from basal mammals, to basal primates, to monkeys, to apes to humans. But, at the same time, you could also argue that the digestive system and the teeth have become less complex in that same lineage. In fact, the teeth may have repeatedly vacillated between more complex and less complex over time, depending on how you define "complex."

-----

Philip Johnson writes:

Evolutionists believe that things become more complex faster than they become less complex, therefore you have a gradual increase in complexity. Things began very simple and are becoming more complex.

But, evolutionists only believe that this is the case for evolutionary lineages that are more complex than their ancestors. Evolutionists do not think that all evolutionary lineages have increased in complexity over time.

For example, look up "scale insect": these are insects that, as adults, lose all of their extremities and resemble a flat scale on the bark of a tree. Related insects and "more primitive" insects have legs, antennae, eyes and wings. In terms of limb diversity, scale insects are less complex than their evolutionary ancestors.

Once again, some lineages have become more complex, some have become less complex, some have alternated between becoming more complex and becoming less complex, and some have become more complex in some ways and less complex in other ways. This is what we mean when we say there is no directionality.

However, I fear that we've moved a considerable distance away from the topic of this thread, and perhaps we should be finding a way to get back to the discussion of the question, "What is life?"

Edited by Bluejay, : Half a sentence was missing.


-Bluejay (a.k.a. Mantis, Thylacosmilus)

Darwin loves you.


This message is a reply to:
 Message 202 by Philip Johnson, posted 12-30-2010 9:18 AM Philip Johnson has taken no action

  
Blue Jay
Member (Idle past 1936 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


Message 233 of 268 (598691)
01-01-2011 8:45 PM
Reply to: Message 223 by GDR
01-01-2011 1:01 PM


Re: What is the simplest life form?
Hi, GDR.

GDR writes:

What is the evidence that evolution guided by natural selection isn't directed?

You've subtly changed "directional" to "directed." As Jar explained upthread, "directional" refers to a sustained direction of change in evolutionary lineages. This we can clearly rule out.

Consider stick insects (a.k.a. phasmids; order Phasmatodea). Primitive insects evolved wings, and basal phasmids retained wings. Some lineages of phasmids, however, lost them. Then, some members of these wingless lineages re-evolved wings.

Such back-and-forth dynamics in the "direction" of evolution is exactly what we mean by "lack of directionality."


-Bluejay (a.k.a. Mantis, Thylacosmilus)

Darwin loves you.


This message is a reply to:
 Message 223 by GDR, posted 01-01-2011 1:01 PM GDR has replied

Replies to this message:
 Message 234 by GDR, posted 01-01-2011 10:45 PM Blue Jay has seen this message

  
Blue Jay
Member (Idle past 1936 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


Message 248 of 268 (598977)
01-04-2011 3:01 PM
Reply to: Message 247 by ICdesign
01-04-2011 1:20 PM


Re: The Mutation Problem
Hi, ICdesign.

ICdesign writes:

Its not enough to claim he is wrong without showing your own calculations with the correct numbers.

When somebody proposes an alteration to a current mathematical conclusion, showing the alteration to be crap is sufficient to restore the current mathematical conclusion.

This idiot assumes that all individuals with harmful mutations die without contributing to the gene pool.

Then, he goes on to estimate that we still inherited 4 million harmful mutations from individuals who, according to his assumptions, shouldn't have contributed to our gene pool.

Based on that, he worked out some more numbers that adjust the current human-ape split from 5 million years to 60 million years.

Thus, when we rule out his obviously flawed math, we don't arrive at 60 million years: rather, we arrive at 5 million years, as before.

But, this is off-topic here: personally, I think we could have continued it at the "problems with evolution" thread. Still, I think it's time for you to start a new thread if you want to discuss this any further.


-Bluejay (a.k.a. Mantis, Thylacosmilus)

Darwin loves you.


This message is a reply to:
 Message 247 by ICdesign, posted 01-04-2011 1:20 PM ICdesign has replied

Replies to this message:
 Message 249 by ICdesign, posted 01-04-2011 4:29 PM Blue Jay has taken no action

  
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