what is life?

[Listener]

There is no gradient of aliveness.  With all due respect to the classic movie, you can't be "mostly dead."  Some things appear to be dead but are really alive, but that is only because their life processes have slowed down to such an extent that they are difficult to perceive.  Even with the simplest bacteria, there is no problem of discerning whether they are still living or have died.

Being dead is only one possible way to not be alive. A rock is neither alive, nor dead. I'll happily agree that being dead is a discrete notion. That doesn't mean that being alive is.

I remember reading in some novel somewhere that the only conclusive proof that something is alive is if it can be killed.

Which sheds new light on the Immortality thread, doesn't it? 

[Mr. Tweedy]

I reject the city because it does nothing of itself.  It is a puppet: It moves only because the people inside it move, and only when they tell it to.  Although a human may rely on the bacteria that live in his/her body, the human's activities are self-initiated.  A living city would be a city that goes about its own activities for its own benefit, with the help and cooperation of its human inhabitants, perhaps, but not under their direct control or for their direct benefit.

The human and the bacteria live in symbiosis: Each helps the other, but they are discrete entities going about their own self-serving business.  There is no symbiosis between Chicago and its inhabitants.  Chicago exists solely for its inhabitants and has no meaning or definition aside from them.

[eytanz]

Do you also reject trees as being alive? A tree doesn't move, and it doesn't inititate anything. To the extent that a city is alive, it is far closer to a tree than to a man.

But mostly, your argument feels circular - you say there is no symbiosis between Chicago and its inhabitnats. Why not? As far as I can tell, the argument you are making goes:

- A city does not have goals because it is not alive.
- Because it has no goals, it is not alive.

You can argue for one, or the other, but not both, and certainly you cannot justify the two statements based on each other.

[slic]

I think we've glossed over eytanz's excellent point about "Bicentenial Man" - Essentially you have a robot that piece by piece replaces his "robot" parts with organic ones - including digestion, pulmenary, circulatory, etc.  At what point did he stop being "dead" and start being "alive"?

A living city would be a city that goes about its own activities for its own benefit, with the help and cooperation of its human inhabitants, perhaps, but not under their direct control or for their direct benefit.

What about coral?  The city example was to help clarify the "attributes of aliveness", but also to point out that we only define life using our very limited senses, and current knowledge (nodding towards Sayeth).  Granted, I do think a city is more rock than tree, but why exactly do I think a leaf is alive and a shell isn't?

There also seems to be a continence of life as a definition of life.

What about seed pods?  They can go dormant (non-living) for years and years.  Are we saying that life must be Organic in nature?  That a metallic creature can never be alive?  Going back to "Bicentenial Man", if you get an artificial arm or heart are you less alive than I am?

[Thaurismunths]

There also seems to be a continence of life as a definition of life.

What about seed pods?  They can go dormant (non-living) for years and years.  Are we saying that life must be Organic in nature?  That a metallic creature can never be alive?  Going back to "Bicentenial Man", if you get an artificial arm or heart are you less alive than I am?

Do you consider sperm alive? How about chicken eggs from the store? Are they 'life forms'?
No, they are blobs of organic matter, gametes, seeds of life. They are the vehicle through which life spreads, but they-themselves are not 'alive' until something else sparks them. Then they are no longer sperm, or eggs, or seeds, they become fetuses and sprouts.

Organic just means 'carbon-based'. Does all life have to be based on carbon structures? No, not necessarily, but all life on Earth is.  As there are no currently classified life forms that are not carbon-based, the distinction is purely academic. I think the limitation to carbon-based only matters if you want to exclude robots and aliens from the status of "alive".

Why would replacing components make you less alive?
First off, I don't require things be carbon-based to be living.
Secondly, life is an emergent property, something that exists beyond the sum of a unit's parts.

[Mr. Tweedy]

Do you also reject trees as being alive? A tree doesn't move, and it doesn't inititate anything. To the extent that a city is alive, it is far closer to a tree than to a man.

But mostly, your argument feels circular - you say there is no symbiosis between Chicago and its inhabitnats. Why not? As far as I can tell, the argument you are making goes:

- A city does not have goals because it is not alive.
- Because it has no goals, it is not alive.

You can argue for one, or the other, but not both, and certainly you cannot justify the two statements based on each other.

Trees do move and they do initiate things.  Their movements are subtle and slow, but they are always moving water up from their roots to their leaves, moving specific quantities of gasses into and out from their leaves, growing toward sources of water, tossing out pollen, etc.  All of these activities are tree-initiated and for the benefit of the tree.

A city does not move and initiates nothing.  It sits inert until humans come along to flip its switches and turn its keys.  Humans animate it and without humans it is nothing.  A tree is a thing unto itself; it doesn't have a lot of little tree-people running around inside it, flipping switches.

A city does only what people make it do.  A tree does its own thing.

[Thaurismunths]

Do you also reject trees as being alive? A tree doesn't move, and it doesn't inititate anything. To the extent that a city is alive, it is far closer to a tree than to a man.

But mostly, your argument feels circular - you say there is no symbiosis between Chicago and its inhabitnats. Why not? As far as I can tell, the argument you are making goes:

- A city does not have goals because it is not alive.
- Because it has no goals, it is not alive.

You can argue for one, or the other, but not both, and certainly you cannot justify the two statements based on each other.

Trees do move and they do initiate things.  Their movements are subtle and slow, but they are always moving water up from their roots to their leaves, moving specific quantities of gasses into and out from their leaves, growing toward sources of water, tossing out pollen, etc.  All of these activities are tree-initiated and for the benefit of the tree.

A city does not move and initiates nothing.  It sits inert until humans come along to flip its switches and turn its keys.  Humans animate it and without humans it is nothing.  A tree is a thing unto itself; it doesn't have a lot of little tree-people running around inside it, flipping switches.

A city does only what people make it do.  A tree does its own thing.

Mitochondria.

[Russell Nash]

if you get an artificial arm or heart are you less alive than I am?

Is an amputee less alive? A parapelegic?  A person 50 pounds lighter than you?

[ClintMemo]

A city does only what people make it do. 

If a city had automated systems to carry out necessary tasks, would that make it alive?
How many systems would it take and which ones?


I think a lot of the issue comes from point of view and what you include in your entity when you decide if it is alive or not.

If I replace everything on my body and become just a brain in a jar am I alive?
What if I replace my brain with a computer AI?  (hehe - a chip zombie)
If I do both are both things alive or dead?  and which is actually "me"?   

[slic]

It sits inert until humans come along to flip its switches and turn its keys.

What about "Spock's Brain"? On a side note-is there no cool idea that can't be compared to an episode of Star Trek (TOS)?  So if a city had a "purpose", it would be alive?

Is an amputee less alive? A parapelegic?  A person 50 pounds lighter than you?

This was along the lines of what Bicentenial Man's lawyer argued.  Of course, they are alive, just as much as a person with an artificial heart.

Just to be clear, I have a very wide definition of life.

I was working my way towards the idea if you could somehow transplant your brain into a rudimentary robotic body, shouldn't you still be considered alive? So, isn't it the seat of consciousness that constiutes life?

I don't think life requires any biological functions, I am a strong proponent of the idea that the Skynet-type AI is a lifeform.

Remember this:

Perhaps life is made up of two parts:
Interaction with the environment and rudimentary (or better) self awareness.

To paraphrase the old Zen nugget - if you live in a basement all alone and no one ever sees you, were you ever really alive?

[Mr. Tweedy]

What about mitochondria, Thaur?  They are an organelle of the cells in which they exist, despite their unusual quirks.  They serve the needs of the cell and cannot exist independently.  What if the kidney had discrete DNA?  It would still be a human organ.

I think the idea of replacing organs making one less alive is silly: A mechanical heart performs the same function as a fleshy one.  The important thing is that blood gets pumped.  Bicentennial Man is alive, as is my junkyard robot, as is a Cyberman, as are energy beings and crystal beings and silicon beings that have populated so man Star Trek episodes.  They do all the things required to meet the definitions of life.  What they are made of isn't important.

[slic]

What they are made of isn't important.

Then all the points about metabolism, reproduction, motion, etc. are moot.  Silicon lifeforms maybe powered by light, or energy beings by pressurized hydrogen (why couldn't the sun be alive, but just thinks really really slowly?).

This is what I was getting at way back.  While simple being able to move doesn't imply life, neither does motionless imply non-life.  If something/someone hibernates
for 100,000 years, how do we know they are alive?

So in a human time scale, my fuzzy line is this at what point do you consider a "conversation-bot" to be alive?

[eytanz]

What about mitochondria, Thaur?  They are an organelle of the cells in which they exist, despite their unusual quirks.  They serve the needs of the cell and cannot exist independently.  What if the kidney had discrete DNA?  It would still be a human organ.

I still don't get this. You keep appealing to the notion of "needs", insisting that non-living things serve the needs of living things but not vice versa. But what I don't understand is how do you determine what has needs and what doesn't?

How do you know that it is the mitochondria which serves the need of the cell, rather than vice versa? What criteria tells you that Manhattan serves my needs rather than vice versa?

[Russell Nash]

What about mitochondria, Thaur?  They are an organelle of the cells in which they exist, despite their unusual quirks.  They serve the needs of the cell and cannot exist independently.  What if the kidney had discrete DNA?  It would still be a human organ.

I still don't get this. You keep appealing to the notion of "needs", insisting that non-living things serve the needs of living things but not vice versa.

By that definition a Ferrari is alive and the owner isn't, because of all the time he has to spend to keep it on the road.

[Mr. Tweedy]

What about mitochondria, Thaur?  They are an organelle of the cells in which they exist, despite their unusual quirks.  They serve the needs of the cell and cannot exist independently.  What if the kidney had discrete DNA?  It would still be a human organ.

I still don't get this. You keep appealing to the notion of "needs", insisting that non-living things serve the needs of living things but not vice versa.

By that definition a Ferrari is alive and the owner isn't, because of all the time he has to spend to keep it on the road.

Grr!  No!

The Ferrari is not alive because it does absolutely nothing to maintain itself.  It's just a thing: It sits there, doing nothing, waiting for something to come along and make it move.  The man maintains the Ferrari for himself, because he enjoys it.

[Mr. Tweedy]

What about mitochondria, Thaur?  They are an organelle of the cells in which they exist, despite their unusual quirks.  They serve the needs of the cell and cannot exist independently.  What if the kidney had discrete DNA?  It would still be a human organ.

I still don't get this. You keep appealing to the notion of "needs", insisting that non-living things serve the needs of living things but not vice versa. But what I don't understand is how do you determine what has needs and what doesn't?

How do you know that it is the mitochondria which serves the need of the cell, rather than vice versa? What criteria tells you that Manhattan serves my needs rather than vice versa?

Because a mitocondrion is a unit in a functional whole.  A mitocondrion by itself cannot maintain its own structure, cannot reproduce, can do nothing.  It needs to united with the other parts of the cell in order to function.

An organ remains intact and alive only by its union with the other organs, by serving the needs of the organism.  You can't just have organs running around on their own.  They have to be part of a whole in order to have any function or relevance.  To talk about an organism serving the needs of the organ is silly because an organ cannot be defined except as a part of the organism.

Take my workplace.  Advertising sells and makes ads for the paper.  The pressmen print it.  The newsroom writes the articles.  Photographers take the pictures.  The managers... do something or other... I guess.  It would make not sense to talk about the paper serving the needs of advertising as if advertising were the crucial piece and all other departments existed just to prop it up.  All the parts are necessary and every part is worthless and non-functional without every other part.  The paper is the organism and all the departments are organs.  Each organ works to support the whole organism and is supported itself only because it is a piece of the organism.  We have to define the departments with reference to the paper, not vice versa.

[Thaurismunths]

What about mitochondria, Thaur?  They are an organelle of the cells in which they exist, despite their unusual quirks.  They serve the needs of the cell and cannot exist independently.  What if the kidney had discrete DNA?  It would still be a human organ.

I still don't get this. You keep appealing to the notion of "needs", insisting that non-living things serve the needs of living things but not vice versa. But what I don't understand is how do you determine what has needs and what doesn't?
How do you know that it is the mitochondria which serves the need of the cell, rather than vice versa? What criteria tells you that Manhattan serves my needs rather than vice versa?

Because a mitochondrion is a unit in a functional whole.  A mitochondrion by itself cannot maintain its own structure, cannot reproduce, can do nothing.  It needs to united with the other parts of the cell in order to function.

In fact Mitochondria do exist outside of a cell, they're called "bacteria". But this bacteria has become so specialized that it doesn't have to tools for gathering nutrients on its own and needs them brought to it. Take a mitochondria out of a cell and drop it in solution and it will continue functioning. Also, mitochondria are responsible for their own division, the cell doesn't do it for them.

An organ remains intact and alive only by its union with the other organs, by serving the needs of the organism.  You can't just have organs running around on their own.  They have to be part of a whole in order to have any function or relevance.  To talk about an organism serving the needs of the organ is silly because an organ cannot be defined except as a part of the organism.

This is exactly what the some Hindu (Hare Krishna) believe. If you think about it, the stomach is the ultimate enjoyer of all our labors.

Take my workplace.  Advertising sells and makes ads for the paper.  The pressmen print it.  The newsroom writes the articles.  Photographers take the pictures.  The managers... do something or other... I guess.  It would make not sense to talk about the paper serving the needs of advertising as if advertising were the crucial piece and all other departments existed just to prop it up.  All the parts are necessary and every part is worthless and non-functional without every other part.  The paper is the organism and all the departments are organs.  Each organ works to support the whole organism and is supported itself only because it is a piece of the organism.  We have to define the departments with reference to the paper, not vice versa.

First Off:
You ad department IS the most important part of your paper. That's where the money comes from to pay your salary and keep the presses running. Also the Ad department IS independent. If you took the whole ad department, the printing department, the finance department, and the shipping department, cut them all up, put them all in different offices, each one would be able to function whole on its own. There are whole industries based around just such ideas.

Secondly:
By your definition, you are not alive.
You, so much as you would like to believe, are not alive any more than your ad department is.
You can do small things to maintain yourself, such as eating and working out, but where do you get your food? Your clothes? You fuel? Your shelter? Your comfort? From other organs.
No man is an island any more than any organ is. Some are just more directly dependant on their supply chain.

[slic]

Thaurismunths, sir, I concur with the above.

Life isn't about parts, and it's not just about what those parts do either.

[ClintMemo]

As I tried to elude to a screen or so ago (and apparently failed because nobody else picked up on it ), you have to take a collection of things that make up some type of system and then decide if the system is alive or not.
How do you decide?  Beats me.  If I knew that, then the topic-which-shall-not-be-mentioned would no longer be controversial.

[Mr. Tweedy]

What about mitochondria, Thaur?  They are an organelle of the cells in which they exist, despite their unusual quirks.  They serve the needs of the cell and cannot exist independently.  What if the kidney had discrete DNA?  It would still be a human organ.

I still don't get this. You keep appealing to the notion of "needs", insisting that non-living things serve the needs of living things but not vice versa. But what I don't understand is how do you determine what has needs and what doesn't?
How do you know that it is the mitochondria which serves the need of the cell, rather than vice versa? What criteria tells you that Manhattan serves my needs rather than vice versa?

Because a mitochondrion is a unit in a functional whole.  A mitochondrion by itself cannot maintain its own structure, cannot reproduce, can do nothing.  It needs to united with the other parts of the cell in order to function.

In fact Mitochondria do exist outside of a cell, they're called "bacteria". But this bacteria has become so specialized that it doesn't have to tools for gathering nutrients on its own and needs them brought to it. Take a mitochondria out of a cell and drop it in solution and it will continue functioning. Also, mitochondria are responsible for their own division, the cell doesn't do it for them.

An organ remains intact and alive only by its union with the other organs, by serving the needs of the organism.  You can't just have organs running around on their own.  They have to be part of a whole in order to have any function or relevance.  To talk about an organism serving the needs of the organ is silly because an organ cannot be defined except as a part of the organism.

This is exactly what the some Hindu (Hare Krishna) believe. If you think about it, the stomach is the ultimate enjoyer of all our labors.

Take my workplace.  Advertising sells and makes ads for the paper.  The pressmen print it.  The newsroom writes the articles.  Photographers take the pictures.  The managers... do something or other... I guess.  It would make not sense to talk about the paper serving the needs of advertising as if advertising were the crucial piece and all other departments existed just to prop it up.  All the parts are necessary and every part is worthless and non-functional without every other part.  The paper is the organism and all the departments are organs.  Each organ works to support the whole organism and is supported itself only because it is a piece of the organism.  We have to define the departments with reference to the paper, not vice versa.

First Off:
You ad department IS the most important part of your paper. That's where the money comes from to pay your salary and keep the presses running. Also the Ad department IS independent. If you took the whole ad department, the printing department, the finance department, and the shipping department, cut them all up, put them all in different offices, each one would be able to function whole on its own. There are whole industries based around just such ideas.

Secondly:
By your definition, you are not alive.
You, so much as you would like to believe, are not alive any more than your ad department is.
You can do small things to maintain yourself, such as eating and working out, but where do you get your food? Your clothes? You fuel? Your shelter? Your comfort? From other organs.
No man is an island any more than any organ is. Some are just more directly dependant on their supply chain.

Okay, no.

Mitochondria are not bacteria.  They are mitochondria.  They are parts of their respective cells and function only as part of their cell.  You can take a human cell out of a person and keep it alive in a solution.  You can even get it to divide, but that doesn't mean that a human cell is a paramecium.

The stomach enjoys nothing.  The brain does all the enjoying.

Regardless of which department is "more important," each needs all the others.  The ads I make would sit uselessly on my MiniMac without the press people to print them, and I wouldn't get my measly little pay check.  Separating the departments physically makes no difference at all.  Advertising still needs printing, regardless of where on the planet advertising and printing happen to be located.  They cannot function on their own: That would mean making ads that never print and the pressmen putting out rolls of blank paper.

I am alive because my body is involved in a continual, self-actuated process of maintenance and renewal.  I have very little to do with this: I stick food in the food hole, but my life processes are almost entirely automatic.  The specific details of how I obtain the food are incidental and not important to defining me as "alive."

[Thaurismunths]

Okay, no.

"No." what?

Mitochondria are not bacteria.  They are mitochondria.  They are parts of their respective cells and function only as part of their cell.  You can take a human cell out of a person and keep it alive in a solution.  You can even get it to divide, but that doesn't mean that a human cell is a paramecium.

No, but that does mean it's living.
Please remember; we aren't arguing about the nature of human cells. We are arguing about the definition of "life."
According to the Endosymbiotic Theory,  mitochondria are a symbiote in the cell, not a portion of it. They are self regulating, metabolizing (well, kind of), carbon based, water dependant, reproductive, adaptable entities: That means they are "living" things. Whole and independent.
Mitochondria were prokaryotes that use to be an independent and self sufficient organism. Just like the ad department of your news paper use to be an independent organism that posted hand bills and sent out town criers. Newspapers date back to the 1400s in Germany (paragraph 1) but advertisements didn't appear until 1640 (paragraph 22), and weren't popular until 1682 (paragraph 8 ). Advertising agencies still exist that aren't imbedded in news papers. They, like bacteria, have adapted to find other ways of surviving and having a purpose.

The stomach enjoys nothing.  The brain does all the enjoying.

The brain only interpret what the stomach says. The stomach enjoys the food, and it sends signals to our brain that says it is satisfied, or not satisfied. We can interpret those signals as needing another doughnut, but it is the stomach that enjoys the doughnut; we can only watch.

Regardless of which department is "more important," each needs all the others.  The ads I make would sit uselessly on my MiniMac without the press people to print them, and I wouldn't get my measly little pay check.  Separating the departments physically makes no difference at all.  Advertising still needs printing, regardless of where on the planet advertising and printing happen to be located.  They cannot function on their own: That would mean making ads that never print and the pressmen putting out rolls of blank paper.

We are arguing about the viability of your ad department, not how useful it is. The meaning of life, purpose, and justification of life are topics for another thread.
My point was that your ad department has a manager (nucleus), assistant manager (ribosome), task managers (RNA), account managers (Lysosome), designers (Golgi app.), checkers (smooth E.R.), etc. It has all the needed functions to take in, process, and produce ads with out the help from other departments. If it does well enough it could hire more people until it eventually splits off. Even if those ads don't go anywhere, just like the mitochondria's ATP doesn't go anywhere, that doesn't mean you department is dead; just pointless.

I am alive because my body is involved in a continual, self-actuated process of maintenance and renewal.  I have very little to do with this: I stick food in the food hole, but my life processes are almost entirely automatic.  The specific details of how I obtain the food are incidental and not important to defining me as "alive."

I didn't define you as non-living. You did.
You said that an organ that can not indefinitely sustain life after it has been cut off from all of its life-giving supply lines is not really a living thing.

*A brief correction: I misspoke saying that Mitochondria were bacteria when they are prokaryotes, predecessors to bacteria.

[edit] clarity.

[Thaurismunths]

As I tried to elude to a screen or so ago (and apparently failed because nobody else picked up on it ), you have to take a collection of things that make up some type of system and then decide if the system is alive or not.
How do you decide?  Beats me.  If I knew that, then the topic-which-shall-not-be-mentioned would no longer be controversial.

Yeah, I brought up the same point and it got glazed over too.

[Mr. Tweedy]

Your mixing origin with function.  It doesn't make any difference how mitochondria became parts of cells, and it doesn't make any difference how newspapers evolved over time.  What matters is what each part does, not how it came to be doing it.

[Mr. Tweedy]

Do you suppose today's story selection was influenced by this thread?

[ClintMemo]

Your mixing origin with function.  It doesn't make any difference how mitochondria became parts of cells, and it doesn't make any difference how newspapers evolved over time.  What matters is what each part does, not how it came to be doing it.

To mix his point and my point...
What matters is whether or not it can do it on it's own.  An advertising department can exist as a separate company or inside of a larger organization.  (IANAB, so I have no idea about mitochondria)

I think this debate only demonstrates that correct answer to "What is life?" may be "I'm not sure"