Why aren't viruses considered to be "alive"?

Originally posted by Cutwolf
If viruses aren't alive, how does stuff like this happen?

See what I previously wrote about adaptation and mutations concerning viral strains. Adaptation and the process of evolving do not necessarily fit in with the definition of a living organism, and do not constitute life just because mutations occur. There are many prerequisites for something to be called a "lifeform" other than just this one process.

Originally posted by TheBorg
And we humans don't "use the mechanisms" on the Earth to do what we want? I'm trying to understand how we're any different from a virus. We're the most prevalent macro-virus in the known universe, since we incorporate everything that we come into contact with.

Again, there is more than one set of criteria used in determining if a to-be organism display the same characteristics as what we determine to be "living". A virus does not meet this criteria, and I'm going to quote myself on a previous post with the following information:

1. The ability to change and respond to any given environment (viruses do not change form in any way based on this)
2. Be able to reproduce (viruses need a host cell to do so)
3. Need to have a lifecycle themselves (viruses do not grow, develop or even die...they simply move on in one form or another)
3. Be able to use energy and the ability to obtain it on their own (viruses depend on host cells to fulfill their metabolic functions)

Not only that, but comparing a concept on the Macro vs. Micro scale will not stand up to scrutiny. What may see like a lifecycle process to you in the Macro world view is nothing more than a coincidental set of chemical reactions in the Micro World view. Humans and other lifeforms are composed of many chemicals that combine to make organelles in cellular life, to organs in humans, to cell walls in plant cells, etc. etc. A virus is composed of not much more than a capsid, viral envelop, nucleic acid, and certain proteins. The definition of life reaches far beyond just these few chemicals and if we expand our definition of life to include something to the effect of "evolution of single or multiple chemical compounds" then it would open up a floodgate of new life. With a definition as broad as this Rocks could be considered a living organism, Stars could be considered a living organism, and a slew of other things we associate with being non-living could be as well.

The original poster on this thread asked "Why aren't Viruses considered to be alive?" This has been answered quite thoroughly and the subject has now boiled down to the question of...Why does science classify one object as living and not another that seems to exhibit properties vaguely resembling the characteristics of known living organisms?...which is a completely different subject.

Remember, just because the human mind can think of something does not necessarily make that thought true.

they do live! are react with others of there own kind and environment.
with no air at all.
read New Scientist mag 18 dec 2010
called "live Wires"
microbes deep beneth or feet make a electricity grid? yes.
they grow hair that conducts.
and they link up. they use iron to dump a charge.
and they link up with each other to HELP each other.
ok unbelievable so read it.

Please if some one can put the story
from New Scientist mag 18 dec 2010 live wire.

they do respond to environmental changes.
and respond to each other to help each other.
so now what you set as life.
makes them LIFE!
if no one puts the article up I will try to photo copy it.
and put it up.
they made us. but that another story.

Try to think of a virus as more chemical than biological, in fact I'm sure "virus" derives from the Latin for "poison".

There is a biological aspect to it, but it lacks any metabolic function that all other life has.

This is exactly why when I hear the word virus, I think spirit. As in cocktails.Which reminds me it's time to go to the store.