aglassey-ga
There are two components of your Answer: biological and philosophical.
Here is the biological component of the Answer, excerpted from the
college biology textbook, "Biology," by Villee, Solomon and Davis, CBS
College Publishing, 1985:
There are 8 criteria for life [ I will include brief descriptions of
each]:
1) Specific organization
"Each kind of organism (living thing) is recognized by its
characteristic appearance and structure...Although organisms vary
greatly in size and appearance, all (except the viruses **Note:
viruses can carry on metabolism and reproduces only by utilizing the
metabolic machinery of the cells they parasitize, and so are said to
be on the borderline between living and non-living things) are
composed of basic units called cells."
2) Metabolism
"In all living organisms chemical reactions take place that are
essential to nutrition, growth and repair of cells, and conversion of
energy into usable forms. The sum of all the chemical activities of
the organism is called metabolism."
3)Homeostasis
"The tendency of organisms to maintain a constant internal environment
is termed homeostasis, and the mechanisms that accomplish this task
are known as homeostatic mechanisms."
4) Growth
"Some nonliving things appear to grow. Crystals may form in a
supersaturated solution of a salt; as more of the salt comes out of
solution, the crystals may enlarge. However, this is not growth in the
biological sense. Biologists restrict the term "growth" to those
processes that increase the amount of living substance in an organism.
Growth, therefore, is an increase in cellular mass that is brought
about by an increase in the size of the individual cells, by an
increase in the number of cells, or both."
5) Movement
"Movement, though not necessarily locomotion (moving from one place to
another) is another characteristic of living things...The streaming
motion of the living material in the cells of the leaves of plants is
known as cyclosis...Locomotion may result from...amoeboid motion."
6) Responsiveness
"Living things respond to stimuli, physical or chemical changes in
their internal or external environment."
7) Reproduction
"One of the fundamental tenets of biology is that, 'all life comes
only from living things.' If there is any one characteristic that can
said to be the very essence of life, it is the ability of an organism
to reproduce its kind."
8) Adaptation
"the ability of a species to adapt to its environment is the
characteristic that enables it to survive the changing world.
Adaptations are traits that enhance an organism's ability to survive
in a particular environment. They may be structural, physiological,
behavioral, or a combination off all of these."
The above eight points are about as close as one can get to a
definition of life from a biological standpoint.
Philosophically, the answer is not as clear cut. I will therefore,
provide one of what I think are the more pressing philosophical
challenges to the "What is life?" question of our day, and leave you
to draw your own conclusions.
The realm of computer programs which are "intelligent" are pushing the
traditional definitions of "life." Artificial intelligence (AI)
programs have been said to have "self-awareness," and we all know that
certain computer viruses (note the parallel to their biological
counterpart) reproduce themselves (i.e. the self-replicating "worms").
Indeed, the entire lexicon of terminology for computer science is
eerily biology-like: Computers have their own distinct "environments"
in which self-aware programs "replicate" themselves. These programs
contain sets of instructions known as "code" which make them what they
are (sounds like DNA, the genetic material which "codes" for life,
doesn't it?") Programs "evolve" as life has done on Earth since its
inception in the briny, prehistoric seas.
Fundamental chemical elements such as carbon (C)make up biological
life as we know it. Silicon (Si)--found in ordinary beach sand-- is
the primary element for the computers. It is interesting that the
elements of carbon and silicon have been around on earth since it
became a planet. We know carbon gave "birth" to life as we know it.
And now it seems silicon has given "life" to machines which can think,
reason, react and replicate themselves.
As evolution continues, it may be possible to see "organisms"
comprised of carbon AND silicon. The whole issue of bioengineering is
beyond the scope of this question, but it definitely raises the
question of "What is life--what defines it?"
The following link is to Kurzweiller's site dedicated to Artificial
Intelligence and an issue known as "The Singularity--that point in
time when technology evolves so rapidly as to be beyond human
understanding:
http://www.kurzweilai.net/index.html?flash=2
Google search strategy:
Keywords:
"Definition of life?":
[ ://www.google.com/search?hl=en&lr=&ie=UTF-8&oe=UTF-8&safe=off&q=definition+of+life%3F
]
"Artificial life":
[ ://www.google.com/search?hl=en&lr=&ie=UTF-8&oe=UTF-8&safe=off&q=artificial+life
]
"life evolution":
://www.google.com/search?hl=en&lr=&ie=UTF-8&oe=UTF-8&safe=off&q=life+evolution
Good luck to you in continuing your inquiries!
omniscientbeing-ga |
Request for Answer Clarification by
aglassey-ga
on
12 Sep 2003 05:33 PDT
Hi OB, and thanks for your response.
After reading your answer, I have had to re-read my original question
because, while I believe that you have answered my question as worded
(and therefore discharged your obligation), I realize that I still
don't have an answer to my question as intended. Let me explain, and
then I'll ask if you wish to pursue a further definition.
Your response regarding the biological aspects of my question provided
me with the attributes of a living thing. These attributes are used
by biologists to determine whether something is alive or not. As an
aside, these attributes are simply clues: they can't be applied
consistently.
I think my question, better phrased, should be: "What is 'life'"?
What is missing from the cell (or leaf or dog or person) one second
past its death, as compared with the same cell one second prior to its
death? Is it just a machine function or is there an additional
ingredient required to bring a collection of molecules "to life"? If
there is an additional ingredient, what is it?
Thanks for your help.
|
Clarification of Answer by
omniscientbeing-ga
on
12 Sep 2003 09:29 PDT
<<"What is 'life'"?
What is missing from the cell (or leaf or dog or person) one second
past its death, as compared with the same cell one second prior to its
death? Is it just a machine function or is there an additional
ingredient required to bring a collection of molecules "to life"? If
there is an additional ingredient, what is it?>>
aglassey-ga,
One second after death as opposed to one second prior, what's missing
from the cell and the organism as a whole is ongoing metabolism and
responsiveness. I didn't say "growth" or "movement" (although that's
true in most cases, too)because in some cases, mammalian hair and
nails continue to grow a few days after death, and if you cut a
chicken's head off, it may run around for a few seconds due to nerve
reflexes, but the chemical processes of life cease, and the organism
is no longer responsive to anything.
Basically, although life can be described by the "machine functions"
as you desribed them, many people consider a spiritual component to be
what defines human life, or perhaps higher mammalian life so as to
include their pet dogs and cats, however most people don't consider a
slime-mold or other "lower" life forms to have a "soul." Whether this
is just an anthropomorphic predjudice, or has some truth in it, I
can't say with certainty, but it is a topic commonly included in
discussions of "what is life?"
Along these lines, pugwashjw-ga's Comment dealing with "active
life-force" is another way of distinguising "alive" from "dead." It is
also a myth of sorts that the human "soul" departs from its earthly
body just after death. Refer also to the many "near-death experiences"
where people reported a detachment sensation, of having floated
outside of their bodies.
Basically, if you consider life from a purely biological standpoint,
you can answer your Clarified Question using the accepted biological
definition of life, as I have presented it to you. If you intend to
include a philisophical or spiritual aspect to the definition, the
matter becomes much more complicated and open to debate.
I hope this helps.
Sincerely,
omniscientbeing-ga
|
