What is life?

[brendan765]

Nobody knows, opinions please.

[p2u_]

What is life? Nobody knows, opinions please.

1) a song by George Harrison on his 1970 triple album "All things must pass";
2) a song by Black Uhuru on the album "Anthem" (1984);
3) a 1944 non-fiction science book for the lay reader by Nobel laureate Erwin Schrödinger, in which he tries to answer the question in physical/chemical terms;
4) a book (1947) by evolutionary biologist J. B. S. Haldane;
5) An aria ("Che farò senza Euridice") in the English translation of Gluck's opera "Orpheus and Eurydice".

[Source: wikipedia]

Paul

[cmg]

1) a song by George Harrison on his 1970 triple album "All things must pass";
2) a song by Black Uhuru on the album "Anthem" (1984);
3) a 1944 non-fiction science book for the lay reader by Nobel laureate Erwin Schrödinger, in which he tries to answer the question in physical/chemical terms;
4) a book (1947) by evolutionary biologist J. B. S. Haldane;
5) An aria ("Che farò senza Euridice") in the English translation of Gluck's opera "Orpheus and Eurydice".

[Source: wikipedia]

Paul

Paul, I have a beach cottage (not fancy at all) on the northshore of the island of Kaua'i.  I think you need to get out of Russia for a few weeks . . .

[p2u_]

Paul, I have a beach cottage (not fancy at all) on the northshore of the island of Kaua'i.  I think you need to get out of Russia for a few weeks . . .

I see what you mean. Well, I was just playing with my neigbor's Apple iPhone 5; more specifically with Siri. If my previous reply didn't make sense, please, blame her. First I told her I wanted to jump off a bridge because I didn't understand the aim of this topic. In the sweetest voice, she announced that there were 4 bridges available for that purpose near my location. Some femme fatale, don't you think?

Paul

[lostinidlewonder]

Life is the opposite of death.

[outin]

Life is the opposite of death.

What is death then?

[lostinidlewonder]

What is death then?

When something is incapable to interact with the world.
When the living cells of the living organism stop functioning.
When the living entity stop breathing.

[outin]

When something is incapable to interact with the world.
When the living cells of the living organism stop functioning.
When the living entity stop breathing.

So life is breathing, cell function and ability to interact. Case closed 

[blessyou]

LOL.. simple as that...

[49410enrique]

[drexo]

The universe we observe has precisely the properties we should expect if there is, at bottom, no design, no purpose, no evil, no good, nothing but blind, pitiless indifference.

Doesn't really answer your question though 

[Bob]

I remember a list of determining what's alive from biology class.  I forget what all the criteria are.

One of them was the ability to reproduce though.  It ruled out bacteria or viruses or something.  But it also meant donkeys (?) weren't alive since they couldn't reproduce. 

[j_menz]

Life is what people had before they replaced it with television.

[drexo]

Life is what people had before they replaced it with television.

And they've replaced television with computer. I'm eager to see what will happen next. Nanotechnology anyone

[rachmaninoff_forever]

  I said this before.

There's several  we use for discerning living from dead:

Metabolism - every living thing has a metabolism

response to stimuli - every living thing responds to stimuli

composed of cells - every living thing is composed of cells

Reproduction - this is probably the biggest one; every living thing has the ability to reproduce


I know that I'm missing a few, but those are just a few to start off with.  But take note this is how we determine living from dead concerning life on EARTH.  We don't know about extraterrestrial life forms, because we haven't seen any yet.  Or at least we don't know if we've seen any.

[rachmaninoff_forever]

When something is incapable to interact with the world.
When the living cells of the living organism stop functioning.
When the living entity stop breathing.

Not all living things breathe.

[j_menz]

  I said this before.

There's several  we use for discerning living from dead:

Metabolism - every living thing has a metabolism

response to stimuli - every living thing responds to stimuli

composed of cells - every living thing is composed of cells

Reproduction - this is probably the biggest one; every living thing has the ability to reproduce

Is there a (non circular) definition of metabolism that wouldn't also include a city, or a shopping mall?

Many non living things respond to stimuli. My TV turns on when I hot the remote button, for example.

Viruses are considered living things, but are not composed of cells.

The pre-pubescent, the post-menopausal and the infertile may question your excluding them from among the living.

[rachmaninoff_forever]

Is there a (non circular) definition of metabolism that wouldn't also include a city, or a shopping mall?

Many non living things respond to stimuli. My TV turns on when I hot the remote button, for example.

Viruses are considered living things, but are not composed of cells.

The pre-pubescent, the post-menopausal and the infertile may question your excluding them from among the living.

They have to exhibit most of the qualities.  I haven't mentioned all of the, because I forgot a few...

And cities are composed of living people...  So...

Where did you get that viruses are alive?  They're not.

[j_menz]

Where did you get that viruses are alive?  They're not.

They evolve, they reproduce, they metabolise.  I appreciate that there is a debate amongst scientists as to their classification as a life form, but that debate in part illuminates the OP's question.

[rachmaninoff_forever]

They evolve, they reproduce, they metabolise.  I appreciate that there is a debate amongst scientists as to their classification as a life form, but that debate in part illuminates the OP's question.

It can't reproduce on it's own.  It must have a host cell.

And it can't move under it's own power.

There we go!  Thought of two more.

They also don't have a metabolism because they don't consume energy, and I don't think they respond to external stimuli.  I'll have to check on that.

[rachmaninoff_forever]

Is there a (non circular) definition of metabolism that wouldn't also include a city, or a shopping mall?

Many non living things respond to stimuli. My TV turns on when I hot the remote button, for example.

Viruses are considered living things, but are not composed of cells.

The pre-pubescent, the post-menopausal and the infertile may question your excluding them from among the living.

Turning on a TV isn't stimulus related. 

You can't condition a TV to turn on when you hit the remote, and it can't get desensitized to it. 

[j_menz]

It can't reproduce on it's own.  It must have a host cell.

And it can't move under it's own power.

Neither can I.

Neither can a mushroom.

[j_menz]

Turning on a TV isn't stimulus related. 

You can't condition a TV to turn on when you hit the remote, and it can't get desensitized to it. 

Replace TV with sunflower and remote with sunlight.

Explain the difference.

[rachmaninoff_forever]

Replace TV with sunflower and remote with sunlight.

Explain the difference.

The amount of sunlight affects the amount of growth the flower exhibits.

Every sunflower reacts to sunlight differently.  Two flowers can get the same amount of sunlight but they won't grow exactly the same way,

too much or too little sunlight can kill a flower.

And I know some plants actually change shape to accommodate to different ammounts of sunlight and different environments.

A TV and a remote control is nothing like that.

[lostinidlewonder]

Not all living things breathe.

Maybe not oxygen but they all breath something.

Not all living things can reproduce though, maybe if you mean cell division within the entity then all things can reproduce I guess except single celled organisms... but they usually reproduce asexually anyway (but I'm sure you could come across a single celled organism which is unable to reproduce).

[rachmaninoff_forever]

Maybe not oxygen but they all breath something.

Touché.
 

[j_menz]

The amount of sunlight affects the amount of growth the flower exhibits.

Every sunflower reacts to sunlight differently.  Two flowers can get the same amount of sunlight but they won't grow exactly the same way,

too much or too little sunlight can kill a flower.

And I know some plants actually change shape to accommodate to different ammounts of sunlight and different environments.

A TV and a remote control is nothing like that.

Sunflowers turn the flower so that it maximises its "face" to the prevailing sun. Sunlight = stimulus; Rotation = reaction.  It is not a conditioned response, and it does not desensitise. Those were the criteria you rejected the TV analogy on.

[j_menz]

Maybe not oxygen but they all breath something.

All plants respire, but it would come as a surprise to botanists everywhere if one of them started breathing.

[rachmaninoff_forever]

Not all living things can reproduce though, maybe if you mean cell division within the entity then all things can reproduce I guess except single celled organisms... but they usually reproduce asexually anyway (but I'm sure you could come across a single celled organism which is unable to reproduce).

If they can't reproduce, they would go extinct.  Which would make them nonexistent.

Unless if...

Okay, for the purpose of this argument, let's just say that sharks can't reproduce.

The only way sharks couldn't go extinct would be if...  I don't know, a giraffe?  If a giraffe gave birth to a shark, that would be the only way sharks couldn't go extinct.  Because they can't reproduce on their own.

[lostinidlewonder]

Yeah but what do you call a sterile organism then? It certainly is not dead.

[lostinidlewonder]

All plants respire, but it would come as a surprise to botanists everywhere if one of them started breathing.

Yeah well I guess if I use all of the proper terms to express the function of breathing we would have to write quite a lot

[drexo]

If they can't reproduce, they would go extinct.  Which would make them nonexistent.

Unless if...

Okay, for the purpose of this argument, let's just say that sharks can't reproduce.

The only way sharks couldn't go extinct would be if...  I don't know, a giraffe?  If a giraffe gave birth to a shark, that would be the only way sharks couldn't go extinct.  Because they can't reproduce on their own.

Read some more about allopatric and sympatric speciation.

[j_menz]

If they can't reproduce, they would go extinct.  Which would make them nonexistent.

Unless if...

Okay, for the purpose of this argument, let's just say that sharks can't reproduce.

The only way sharks couldn't go extinct would be if...  I don't know, a giraffe?  If a giraffe gave birth to a shark, that would be the only way sharks couldn't go extinct.  Because they can't reproduce on their own.

Some bacterial species (such as ricketsia and chlamidia) cannot reproduce outside a host cell, in the same way as a virus can't.  Those bacteria are universally considered "life".

[lostinidlewonder]

Could we also say that all Life is Carbon based? Since we have not found any other organisms which are not.

[rachmaninoff_forever]

Sunflowers turn the flower so that it maximises its "face" to the prevailing sun. Sunlight = stimulus; Rotation = reaction.  It is not a conditioned response, and it does not desensitise. Those were the criteria you rejected the TV analogy on.

You could say the flower creating glucose is the reaction while the rotation is...  Whaaaaaaat ever dude!

I should've eddited that out...

I still think it's a bad analogy.  

I'm positive can still condition flowers, I just don't know how.  Because I'm not a gardener...  

An I'm sure a flower can get desensitized to an environment.  If you like change the amount of sunlight, temperature, or the amount of water a little, it'll get used to it.  But if you change it too much then it'll die.  

[rachmaninoff_forever]

Could we also say that all Life is Carbon based? Since we have not found any other organisms which are not.

Or we could be more specific and say that all life are made of amino acids.  But not everything that's made of amino acids are life.

[rachmaninoff_forever]

Some bacterial species (such as ricketsia and chlamidia) cannot reproduce outside a host cell, in the same way as a virus can't.  Those bacteria are universally considered "life".

Aaaaaarghghghg!!!

I'll be back.  I have to do some research.

[lostinidlewonder]

True rach....

What about... everything that is alive moves in some way by their own, death things cannot move.

[drexo]

True rach....

What about... everything that is alive moves in some way by their own, death things cannot move.

Your definition of death, is?

[rachmaninoff_forever]

Some bacterial species (such as ricketsia and chlamidia) cannot reproduce outside a host cell, in the same way as a virus can't.  Those bacteria are universally considered "life".

Okay, I got you right here!

Okay so sure they can't reproduce outside a host cell, so they ACT like viruses, BUT!!!

A virus isn't made of cells, and the actual capsule doesn't have a metabolism.

So for something to be alive, it has to meet like most of the  6 or 7 criterion for being alive.  The virus fails to meet three but the bacteria only fails to meet one!

CHECK...
MATE...
 

[drexo]

Random Hitchslap:

[j_menz]

So you are saying that there is no one thing that is either necessar or sufficient to establish something is alive, it's a kinda 8 out 10 and you are, 4 out of ten and your not? Life is not so much an absolute as a degree?

[rachmaninoff_forever]

So you are saying that there is no one thing that is either necessar or sufficient to establish something is alive, it's a kinda 8 out 10 and you are, 4 out of ten and your not? Life is not so much an absolute as a degree?

Come on dude...

We get the gist of it okay?

There's only like two things on Earth we can't tell if it's alive or not.  kinda...

We kinda have a universal definition of what's alive, and that works for like 99.9% of the time.