Define the state of being alive. Define it in any way you see fit. Use science, personal opinion, spirituality, or whatever you think best defines the state of being alive.
Actively in use.
This depends on a number of things. I'd say that a living organism is both complex and organised at the same time. I know this leaves a lot of gaps in the definition but this depends on your perspective.
BTW, do you consider viruses as living organisms?
> Define the state of being alive.
> Use science
The standard criteria last I knew was that the most basic unit of life was the cell. Everything alive is a cell or multicellular. Loosen the criteria, and it gets more difficult to exclude chemical reactions.
Another definition I head was a localized reversal of entropy.
> do you consider viruses as living organisms?
Not cells, It does not follow.
>>4
Localized reversal of entropy is a great "think about this" sort of argument. Disregarding that entropy is as inescapable as the laws of thermodynamics, Life could easily be interpreted as a temporary force of "reverse-entropy". A living system tends to make order out of disorder over time. However, the individual processes that create life all seem to bank on entropy.
Digestion is a process that comes to mind first. It is an absolute necessity, as the process of digestion provides energy for the living system to use in its many processes. However, the process of digestion itself takes an organized object (food) and disorganizes it into chemical energy and waste. The energy is then used, and the waste is broken down by microorganisms.
Respiration and circulation could be other examples, where the act of breathing first filters oxygen from the various gases, and then expels waste gas (CO2) from the body.
Entropy finally catches up to life sooner or later, with the degradation of the body's systems and its ability to renew those systems. Using the logic in the statement "life is characterized as a system that appears to reverse entropy over time," death and non-life could be interpreted as "a system characterized by by the lack of any forces that seem to counteract entropy."
The more I think about this, the more complex it seems to get. For instance, a broom can be positively characterized as non-life using the logic in the above paragraph. But in the hands of a person who is using it, a broom seems to to reverse entropy by organizing waste (dust and crap on the floor) into an organized system of "trash." Though this example might seem to muddy up the logic of the argument, I think it actually strengthens it. Dust and crap on the floor can only be considered trash by a living person. Dust and crap on ground outside is not trash, it is simply part of a broader disorganized system. Therefore it seems that just the act of living tends to create the illusion of order throughout the world.
Discordianist philosophy deals a lot with this sort of thing. The illusion of order and the need for people to think of the world as an organized system.
>>5
Thanks for the explanation. It's leagues better than I could give (or care to research)!
entropy will never catch up with me
I think, therefor I am ali... err
If life is the reversal of entropy, than we could also say it is an increase in information.
"If it moves it's alive, salute it.
If it don't move, paint it!"
I think the generally accepted terms for a living thing (as we know life to be) is a self replicating system which interacts with its environment and metabolizes compounds for energy.
I personally don't think virii are living. Perhaps semi-living, as our machines are, but not truly alive.
Make that a SELF ENCLOSED system, separated from its environment.
Sorry, I forget things sometimes.
Being alive is the state of wanting to die.
>>14
The solution is simple.
OP here. My reason for asking this question has more to do with robotics than just biology. I find myself thinking a lot about whether a robot could ever be alive.
Think far into the future, and ask yourself whether a significantly complex machine could ever be considered alive. It's a fun question I think.
It's a question that's been asked over and over again for nearly a century now. It's getting pretty goddamn old and worn by now.
You are alive if you are a self enclosed, active system that is capable of replicating yourself.
Bonus points for reproducing right now
Is a virus alive? Last I checked I believe it missed one of the criteria.
And I think it needs to be built out of cells to be considered "life". Maybe if we encounter extraterrestrial "life" not composed of cells, these strict definitions will change.
Here are Wikipedia Definitions:
1. Homeostasis: Regulation of the internal environment to maintain a constant state; for example, sweating to reduce temperature.
2. Organization: Being composed of one or more cells, which are the basic units of life.
3. Metabolism: Consumption of energy by converting nonliving material into cellular components (anabolism) and decomposing organic matter (catabolism). Living things require energy to maintain internal organization (homeostasis) and to produce the other phenomena associated with life.
4. Growth: Maintenance of a higher rate of synthesis than catalysis. A growing organism increases in size in all of its parts, rather than simply accumulating matter. The particular species begins to multiply and expand as the evolution continues to flourish.
5. Adaptation: The ability to change over a period of time in response to the environment. This ability is fundamental to the process of evolution and is determined by the organism's heredity as well as the composition of metabolized substances, and external factors present.
6. Response to stimuli: A response can take many forms, from the contraction of a unicellular organism when touched to complex reactions involving all the senses of higher animals. A response is often expressed by motion, for example, the leaves of a plant turning toward the sun or an animal chasing its prey.
7. Reproduction: The ability to produce new organisms. Reproduction can be the division of one cell to form two new cells. Usually the term is applied to the production of a new individual (either asexually, from a single parent organism, or sexually, from at least two differing parent organisms), although strictly speaking it also describes the production of new cells in the process of growth.
> Is a virus alive? Last I checked I believe it missed one of the criteria.
It misses all criteria. If you tried to include Viruses, you'd end up including things like fire or nuclear fusion.
A philosophical question doesn't "get old," as it grows and changes over time in response to new knowledge. If you perceive its current state as being stagnant or "worn", you're either ignorant to its development or have no imagination.
I think the term "being alive" is a too superficial.
There are many factors to consider with.
> A philosophical question doesn't "get old,"
Yes, yes it does. New knowledge can answer the question with certainty, or make it moot. Or else there is no new knowledge, and sooner or later all possible answers will be exhausted, and there will be nothing new to add.
This one is falling towards the latter category.
One of the many difficulties in defining life.
For your consideration: Mules...