Define life

My apologies, I misunderstood you some in my haste reading over the thread.

 

@Marla: I am not sure why you are saying a thunderstorm is not reproducing.

When you become a mother won't your kid be smaller than you? That's exactly what a thunderstorm does. It makes a small kid which grows up in time.

Your kid is not a copy of you, even is you reproduced asexually and specifically in sexual reproduction the kid is very different from you.

But if exact replication is what you want, then I have something else for you. A computer virus. It makes exact fully functional copies of itself taking resources from the environment. Would you call that alive?

 

Ok, let's take up the challenge. It is an interesting challenge.

The first thing I will say is remove reproduction from the list. It is neither neccessary (sterile ants) nor sufficient (computer viruses, thunderstorms etc. etc)

Then add this.

Life maintains a boundary between inside and outside. All life must define such a boundary.

 

Storms are purely energy phenomenon. They aren't "using" energy, they are energy.

 

I am really confused here! Storms are made up of air & water in a certain state. How can you say they are pure energy?

 

Ok, I have thought. Neither fire or hurricanes possess a blueprint (DNA) which will produce (practically)exact duplicates of themselves, forever into the future. A hurricane or a fire are the result of physical and chemical conditions and processess found in the external environment. Life is something which transforms its environment (in addition to using it) for the purpose of replicating itself indefinitely. Life sustains life. Physical processes merely play themselves out until all the energy in its environment has been exhausted. Neither fire or hurricanes have the ability to adapt themselves to changing external conditions (energy availability), whereas life continually works the environment and itself in order to produce conditions favorable for the propagation of itself.

 

Robots are capable of intelligence, creating new robots, they are composed of many small parts, as are we. Hows are robots not alive? Because they're made from metal? You're gonna need a reason.

 

Those are the criteria. The definition is further below and it includes Reproduction only given some conditions.

Here it is once more:

1. Stimulus response
2. Metabolism (ability to process things from the environment)
3. Homeostasis
4. Reproduction*

I define life as something that posesses at least the first 3 characteristics AND is the offspring(or product) of something with all characteristics OR can produce offspring with at least the first 3.

The flaw in it would be creatures spontaneously materialized out of a sterile environment and that can't reproduce (and the odds of finding one would be infinitesimal).


P.S. I like your criteria but isn't that included in homeostasis?

 

Dp, if you think carefully, then you will see computer viruses match all your criteria.

It sustains itself as long as possible (just like any biological life) till it is exterminated or runs out of resources (just like biological life). It transforms its environment and can create an exact or inexact copy of itself depending on its internal code (an exact analogy with our DNA).

 

I disagree, a storm is not water and air.

A storm is about the movement of water and air. Just like a wave isn't water, it's the movement of water.

 

So... maybe computer virii are alive. The unique thing about them is the we humans control their environment and are able (to certain extent ) to eliminate them. We might be more god-like than we think. (And that is saying a lot knowing how we always seem to feel we are the center of the universe! )

 

Computer viruses are alive, at least in the sense that real-world viruses are alive. We can all look forward to a future of computer virus rights activists, then.

 

Today's robots who build cars for instance aren't alive because they aren't autonomous. They aren't looking for energy by themselves in the purpose to create copy of themselves.

However, I think we can decently say that Robots in movies like Matrix or Terminator are indeed alive. It's another kind of life, but there's no doubt they behave like a living specie.

 

If you take out homeostatis (for reasons mentioned below) then a computer virus is a life.

Also, I am not sure with this stimulus response thingy. Everything that we know of in this universe responds to some stimulus. When do we say that such response is because of life and not because of something else. A plant moves towards light and we take that as a evidence for life. A bimettalic strip moves away from heat and we do not take that as evidence for life. So arbitrary. So I suggest you remove that too.

Homestatis is ill-defined because for any arbitrary system how do you define statis? When would you say a system is in statis? Specifically, what if the system is chaotic (much of known life is) but sustainable indefinitely. How do you define statis then?

However, a boundary is always well-defined. All life that we know on earth always defines such a boundary. Fire, thunderstorms and computer viruses do not define a boundary and actively maintain it.

 

Computer virus are predeterminated. They aren't autonomous.

When you put an ant right in the middle of a box with two bean in both extremities, you have no way to know in advance in the direction of which bean will go the aunt. The same goes for a plant. When a tree is young you have no way to know where exactly would be the branches once it will be "adult".

Whereas in the case of viruses, they simply behave like we've asked them to behave. They aren't autonomous. The artificial intelligence doesn't exist yet.

 

betazed thats an excellent point and it almost stumped me. But what does a computer virus need in order to maintain its own existence? Nothing. It doesnt need to take anything from its environment in order to maintain itself, because it expels no energy in being itself. Life consumes energy, and it seeks out new sources of energy (or adapts itself) when local conditions suddenly become unfavorable and lacking in readily available sources. Unless specifically programmed to, a computer virus would never be able to adapt itself

This line of thinking seems to be leading towards a god, which has programmed life to propagate itself, but thats OT (even if it appears to be true)

 

Eh! This is like saying Marla singer is not made up of chemicals and but is the reaction of chemicals. it is just a pedantic distinction.

Both your statement and mine are equally correct and equally meaningless

 

So you would assume that a wave is not a movement of water, it's water using energy to move ?

I'm not sure water deliberately uses energy to move.

 

Plants aren't exactly autonomous either. Everything they do is a chemical response to stimuli. Granted, it is a very very very complicated code to decipher, but if you put a plant into a box, with a light source on one side, it will ALWAYS grow toward that light source.

Also, if you stick a computer virus onto the internet, and it propagates independently (i.e. without someone having to e-mail it or download it or whatever), there is no way to predict where it will be in a week's time.

 

Not correct. It requires energy (electricity) and a ecosystem (the computer and its os etc.)

Again not correct. As I said it requires electricity and it also requires raw materials. Memory, disk space, sometimes network bandwdith etc. etc.