What is Life?

This topic was inspired by the topic on Evolution, or more precisely, something I said in that topic where we got side-tracked into a tiny little argument concerning whether a virus was alive or not.

Obviously, viruses exhibit some characteristics that just don't fit in with life.

Outside of a cell, it exhibits the least life-like characteristics. It doesn't reproduce, it doesn't grow, it doesn't utilise energy, it only reacts to the environment and even so it doesn't do it very well.

Inside a cell, it starts reproducing like all get out.

So here I propose the one question.

What is life? Can viruses be said to be alive? Can computer viruses and worms be said to be alive? And if we do create a robot with artificial intelligence, could we say that that is alive too?

The general characteristics of the living beings are these: birth and death, they eat, they move, they act according to their surrounding, they reproduce, they transform food into energy and they adapt to their environment. If something doesn't possess one of these characteristics in any way, it's not alive.

^ what she said.

Case closed. There's really no discussion on this topic, its quite well defined.

Yeah...this is one of those things that has a biological definition. Viruses don't fit that definition; they're not alive.

Artificial intellegence isn't alive, either, it's a machine. Whether or not something is thinking, or capable of thought, there's a fun topic.

Originally posted by La Catrina@Sep 28 2004, 12:08 AM
The general characteristics of the living beings are these: birth and death, they eat, they move, they act according to their surrounding, they reproduce, they transform food into energy and they adapt to their environment. If something doesn't possess one of these characteristics in any way, it's not alive.

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You took one of the most controversial subjects in biology and answered it in one paragraph? I am in disbelief.

How about prion proteins then? They do not respirate (as in "transform food into energy") or eat or move by themselves but they fit every other characteristic youv'e mentioned.

They "reproduce", they adapt to their environment. Thing is, do they really die? That is the big question.

P.S. Individually, ants do not show intelligence and frogs (or was it toads?) don't show thought at all. Studies have shown they act quite a lot like machines.

They don't reproduce, and they don't adapt to certain environments, they are created by them. Not alive, not animals, not intellegent, not sentient.

As for Ants/Frogs: Alive, Animals, not intellegent, not sentient.

Life? Why it's a forum.

Originally posted by Hero of Winds@Sep 28 2004, 03:47 PM
Life? Why it's a forum.

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"Life" isn't well-defined. Geez Khuffie.

If you're looking for a general definition, I've heard it proposed that the minimal requirements for life is an object that is self-preserving and has an inherent ability to reproduce its own kind. This definition doesn't necessarily involve the biological lifeforms you see around you on Earth. Under this definition, a computer virus could count because it is self-preserving simply by sitting there, and it reproduces its own kind.

Biological viruses can't reproduce on their own, true, but they can reproduce under certain conditions (i.e. after entering another cell). So it seems that they count as life. Life forms can be dependent on other life forms for their survival/reproduction, but they're still life forms.

Originally posted by alak
Artificial intellegence isn't alive, either, it's a machine. Whether or not something is thinking, or capable of thought, there's a fun topic.

Yet another reason to consider "souls" or "consciousness" or "minds" separately from an actual body/lifeform, eh? If an AI can exist without a lifeform to contain it, one can extend such thinking to humans, right?

A robot would be considered a lifeform only if it can reproduce its own kind. If robots can only be built by humans, then robots do not have an inherent ability to reproduce, and therefore don't count as lifeforms.

An AI, on the other hand, doesn't necessarily have a body. I would consider it more of a "mind" than a "lifeform."