Life

An article about it:
http://www.astrobio.net/news/article226

It's interesting how something which seems so easy to grasp intuitively is actually very hard to pin down. Is life much less different from non-life than our intuition tells us?

Originally posted by Palynka
Is life much less different from non-life than our intuition tells us?

Yes.

Originally posted by FabianFnas
Yes.

Your answer flies in the face of the evidence that the scientific community has yet to agree to a consensual definition. Again you show how poor a "scientist" you are, besides being a self-admitted xenophobe.

Originally posted by Palynka
Your answer flies in the face of the evidence that the scientific community has yet to agree to a consensual definition. Again you show how poor a "scientist" you are, besides being a self-admitted xenophobe.

You say so only because I'm from Sweden, you racist! 🙂

Would you feel better if I just wrote FAIL and nothing more? 🙂

Now, let's be serious. You're quite right about life. Intiutively we think we know what life is, definition is 'clear': "Life is what is living on Earth." Nothing more. We have not yet encountered any extraterrestrial life form (No, Marsian life is not proven yet, haven't been found), and we cannot even agree upon prions are life or not. We even have different definition about deat of humans, heart-dead or brain-dead.

I say that life is elusive, we don't know yet exactly (scientifically) what life is. We don't want to bring in spiritual definitions here, do we?

Originally posted by FabianFnas
You say so only because I'm from Sweden, you racist! 🙂

Would you feel better if I just wrote FAIL and nothing more? 🙂

Now, let's be serious. You're quite right about life. Intiutively we think we know what life is, definition is 'clear': "Life is what is living on Earth." Nothing more. We have not yet encountered any extraterrestrial life form (No ntifically) what life is. We don't want to bring in spiritual definitions here, do we?

A great person is one that can except spirituality, not fear it..... Life is infinately more than your or my obtuse theorys about it.

Your putting science on a pedastool my friend, for without spirituality none of science, as we know it, would exist.

When I say spirituality, I simply mean ambition,curiosity,creativity, basicly any notion that has driven man or any other creatures to question existance.

I feel sorry for you, if you have never looked at the night sky without scientific agenda, without unexplainable tears,followed by laughter and a strange sense of content in knowing the insignificance of your significant significance....

Originally posted by joe shmo
A great person is one that can except spirituality, not fear it..... Life is infinately more than your or my obtuse theorys about it.

Your putting science on a pedastool my friend, for without spirituality none of science, as we know it, would exist.

When I say spirituality, I simply mean ambition,curiosity,creativity, basicly any notion that has dri ...[text shortened]... nd a strange sense of content in knowing the insignificance of your significant significance....

Sorry, joe, but Fabian is right in this case. I posted this in Science because I was interested in understanding why scientifically it is so hard to pin down a concept we feel is quite important (just look at what a great discovery it would be to find life on another planet) and intuitive. This would be true to everyone, theist or atheist.

Originally posted by Palynka
An article about it:
http://www.astrobio.net/news/article226

It's interesting how something which seems so easy to grasp intuitively is actually very hard to pin down. Is life much less different from non-life than our intuition tells us?

-this answer to your question may seem like a non-answer but it simply depends entirely on exactly what you personally mean by the word “life”.

…It's interesting how something which seems so easy to grasp intuitively is actually very hard to pin down.…

What “life” and “non-life” is in reality is entirely dependent on how you would personally make the distinction -in other words, it is purely subjective.

…http://www.astrobio.net/news/article226.…

This link just argues over the definition of “life” but fails to mention the fact there is no “correct” definition because what we mean by the word “life” (or, indeed, any other word) is, ultimately, purely up to us.
The best we can hope to achieve is to create a definition of “life” that conveniently expresses approximately what most of us vaguely mean by the word but preferably with a definition that is as simple as possible.

The link gives a number of possible definition of life including this one:

…This definition says that life is "a self-sustaining system capable of Darwinian evolution."

But Clark says most life forms technically are not self-sustaining. Animals feed on plants or other animals, plants need microorganisms at their roots to take up nutrients,
....

But why not just define “life” as anything which has either undergone Darwinian evolution or at least has the potential for Darwinian evolution (regardless of whether or not it is “self-sustaining&rdquo😉?
-I think that would be a much more “convenient” definition.

The link goes on to say:

…Clark says that Darwinian evolution is another problematic criteria. How could you tell if something has undergone Darwinian evolution? The time scales involved are enormous - scientists would need a complete understanding of an organism's fossil history before being able to declare that the object is, indeed, alive. .…

-but this is irrelevant to the definition of life because this is just the practical problem of how do we find out if something it truly “alive” as opposed to what we mean by the word “alive”.

Personally I would define life as simply:

“life is anything which has either undergone Darwinian evolution in the past or has the potential for Darwinian evolution in the future (if it was placed in the right environment) or both of these things”

This definition overcomes the problem of the issue of those life forms that are incapable of reproduction (such as sterile bees etc) and thus are incapable of Darwinian evolution in the future. This is because those life forms that are incapable of reproduction must have still come from life that WAS capable of reproduction and those life forms would have still come from life that had undergone Darwinian evolution in the past and thus, according to my definition of “life” above, would still be defined as “life”.

Don’t get me wrong -I don’t believe this is a “correct” definition for “life” because I know there is no such thing as a “correct” definition of a word! -I just personally prefer this definition over the alternatives.
-does anyone feel the same? -I mean, does anyone else prefer my definition of life over all others?

Originally posted by joe shmo
A great person is one that can except spirituality, not fear it..... Life is infinately more than your or my obtuse theorys about it.

Your putting science on a pedastool my friend, for without spirituality none of science, as we know it, would exist.

When I say spirituality, I simply mean ambition,curiosity,creativity, basicly any notion that has dri ...[text shortened]... nd a strange sense of content in knowing the insignificance of your significant significance....

Of what I read in your posting, you don't know me at all. And yet you draw conclusions only because you don't agree with me? Funny...

Answering your question makes me go off-topic, and that I don't want to do, in respect of Palynka.

Don't let this thread be yet another one where religious fundamentalists take over a perfect scientific interesting thread. This is Science Forum, not the Spiritual Forum. If anyone want to discuss spriritual matters about the essence of life, then go there and start a thread about it.

Originally posted by Andrew Hamilton
-this answer to your question may seem like a non-answer but it simply depends entirely on exactly what you personally mean by the word “life”.

[b]…It's interesting how something which seems so easy to grasp intuitively is actually very hard to pin down.…

What “life” and “non-life” is in reality is entirely dependent on how you would person ...[text shortened]... nyone feel the same? -I mean, does anyone else prefer my definition of life over all others?[/b]

That's more or less the type of answer I was hoping for, so thanks for your contribution. 🙂

A few comments, first. Although I agree there is still no consensus about what a correct scientific definition of life is, I fully disagree that there is no such thing as a "correct" definition of a word. Words are labels, so when a chemical element was named "hydrogen", the label was, by construction, correct. Also, I prefer the term "evolution" to the (more restrictive) Darwinian evolution. I don't wish to go into these type of semantics too much, though, so moving on...


What “life” and “non-life” is in reality is entirely dependent on how you would personally make the distinction -in other words, it is purely subjective.
This is the point of my post. How can that be? Life and non-life are so distinct in our reasoning, that we even have a devoted science (Biology) to study the former as distinct from the latter. Although a clear-cut separation seems hard, the distinction is not purely subjective. We can all agree that a lump of rock in space is not alive, but a grazing cow is. The subjectivity is only on where we draw the line.

But why not just define “life” as anything which has either undergone Darwinian evolution or at least has the potential for Darwinian evolution (regardless of whether or not it is “self-sustaining&rdquo😉?
The first problem is that evolution is defined in a way that requires genes and these (if defined by heredity) are defined only for life-forms, closing a purely circular definition. If, by gene, we mean more precisely RNA or DNA genes, then we limit ourselves to a specific type of life (contradicting what we 'want' to define) and we include viruses, which typically are on the borderline but are usually not seen as living.

Evolution doesn't depend on the existence of genes, however, computers are also capable of simulating Darwinian evolution, so that definition of life fails for a different reason.

Originally posted by KazetNagorra
Evolution doesn't depend on the existence of genes, however, computers are also capable of simulating Darwinian evolution, so that definition of life fails for a different reason.

Gene just means an unit of heredity. The latter is only defined for living organisms. That computers can simulate the process doesn't mean that they (along with the code) have the required properties.

Originally posted by FabianFnas
Of what I read in your posting, you don't know me at all. And yet you draw conclusions only because you don't agree with me? Funny...

Answering your question makes me go off-topic, and that I don't want to do, in respect of Palynka.

Don't let this thread be yet another one where religious fundamentalists take over a perfect scientific interesting th ...[text shortened]... uss spriritual matters about the essence of life, then go there and start a thread about it.

I am a fan of science, and am somwhat becoming a fan of SPIRITUALITY....NOT RELIGION....you are lumping the 2 in the same category...

And If you want to talk about Hipocrits, Look at the 3 PAGE's of OFF TOPIC POST that you and kelly Jay left in the " are we helpless without memory thread"

I look forward to your response, but you can have the last word on this.

By the way, I envy your command of the text book.

NOTE*Pehaps "Spirtuality" is a bad term for the context in which I use it.

Originally posted by Palynka
Gene just means an unit of heredity. The latter is only defined for living organisms. That computers can simulate the process doesn't mean that they (along with the code) have the required properties.

What properties don't they have?

Originally posted by KazetNagorra
What properties don't they have?

Heredity. You also seem to forget that we're talking about evolution in the biological sense. Like I said, this is only defined for living organisms, rendering it's use, for defining life, circular by construction.

Originally posted by Palynka
That's more or less the type of answer I was hoping for, so thanks for your contribution. 🙂

A few comments, first. Although I agree there is still no consensus about what a correct scientific definition of life is, I fully disagree that there is no such thing as a "correct" definition of a word. Words are labels, so when a chemical element was named "hyd ude viruses, which typically are on the borderline but are usually not seen as living.

…But why not just define “life” as anything which has either undergone Darwinian evolution or at least has the potential for Darwinian evolution (regardless of whether or not it is “self-sustaining&rdquo😉?
The first problem is that evolution is defined in a way that requires genes and
.…

Actually not quite -remember that when Darwinian evolution was first conceived there was no knowledge of the existence of “genes” and yet evolution was still defined. Grant you that everything that we call “living” that we know of has genes and we have no known examples of Darwinian evolution where genes are not involved (apart from in some computer simulations?), but, hypothetically, one could imagine something just like a living thing which could evolve but passed on its characteristics onto its offspring using information of inheritance stored in some other form other than in what we would refer as “genes” -example; some self-replicating robots may be made to be able to evolve by Darwinian evolution and the information of inheritance stored in their software (using my admittedly imperfect definition of “life“, such robots will be defined as “living&rdquo😉.
The point here I am making is that you could define Darwinian evolution without reference to genes.

…and we include viruses, which typically are on the borderline but are usually not seen as living..…

I am always puzzled to why so many people don’t want viruses to be defined as “living”
-personally I see viruses as “living” because of what I vaguely mean by “life” -but that is just me.

…Although a clear-cut separation seems hard, the distinction is not purely subjective. We can all agree that a lump of rock in space is not alive, but a grazing cow is. .…

I agree that this must be generally true because I assume that the vast majority of people wouldn’t be so unreasonable to define a lump of rock as “living” because that would just be giving a meaning to the word that deviates by an unreasonable extend from what people normally mean by the word.
But, hypothetically, some extremely awkward unreasonable eccentric person could still arbitrarily categorise a rock as “living” in his own mind.
-still, I think you are right -I shouldn’t have said “purely” subjective 🙂