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 I was surprised to learn that there is no universally agreed definition of life:

http://en.wikipedia.org/wiki/Life


The definition of life is growing in importance. We want to know when human life begins for lots of ethical, legal, and religious reasons. We want to know that if we find something crawling around on Mars it can be classified as life. As artificial intelligence evolves, we want to know when to start granting androids rights. And if a human is in a coma, we want to know at what point that individual could be considered no longer alive.

So I was noodling with a functional definition of life that aims to solve our current and future ethical dilemmas. How about defining life as any discreet entity with the following qualities:


  1. Potential to feel pain.
  2. Potential to learn.


This definition keeps our future androids from getting full legal rights, since they can't feel pain. And it would let you pull the plug on anyone who doctor's say has no potential to ever feel pain or learn again. So far, so good.

One thorny issue is that life would begin at conception by this definition. It would be a separate argument as to whether the woman carrying the life has a right to terminate it while it is still in the early potential phase.

My definition keeps a virus from being considered life. And plants too, I think. That feels right. I don't think lettuce needs to be "alive" any more than my watch.

I haven't thought this idea through. I'm just throwing it out there for consideration.

 
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Jan 26, 2009
... oh, and don't believe everything you read on Wikipedia ;-)
 
 
Jan 26, 2009
I think you are confusing "sentience" with "life". This is always a stumbling block in these types of discussions.
I would define "life" as an entity that:
1) has the capacity to reproduce (even if it needs a/multiple partner(s))
2) has the ability to move
3) has some sort of metabolism
I grant that this definition may not be complete as it may include some robotic "life".

However to call an entity "sentient" you need:
1) the capacity to experience suffering
2) the capacity to learn
This definition would then exclude some the lower "life" forms like viruses and may in future be applied to artificial intelligences.

The definition of sentience at answers.com may shed more light on this discussion than my short synopsis can ever hope to achieve.
http://www.answers.com/sentience

Alex
 
 
Jan 26, 2009
I think you need to get outside more, maybe get your hands dirty or even buy a house plant.
Leaving out plants is just plain stupid as they are clearly alive. Trying sending one away to get fixed when it "stops working".
 
 
Jan 26, 2009
I think your "potential to feel pain" is going to include androids.

The only way to asses the ability to feel pain, is to observe that the entity avoids painful stimulus. Give an android a heat sensor, instruct it (or let it learn) to avoid setting off that sensor, connect the sensor output to a strong warning, and voiler, your artificial intelligence is experiencing pain.

The person on life support, depending on the specific injuries and failed organs, might react physically to pain. And, though comatose, might feel pain, just be unable to to react, and we wouldn't know. They might also be able to learn - sounds, smells, daily rhythms. Being comatose and unable to relate or react to what has been learned - how would we know?

I find it ironic that the church now asserts that live begins at conception - and not ovulation, or ejaculation, or even puberty or birth of the parents. The early church recognized children, but not as "people" until confirmed - at puberty. Today we distinguish the age-classes as children and adults. Besides, an act of birth has always been an act of war in the Bible. They needed babies to have a big army in the next generation, to beat off attacks and to attack foes. Today the church still emphasizes births, because that keeps the church growing. Especially when those pesky Muslims keep killing missionaries in Muslim lands.
 
 
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Jan 26, 2009
A XVth century British jurist argued that corporations are not "persons" because they have no body to be tortured and do not have souls to be damned. (Presumably, they can not therefore be held responsible or punished for their misdeeds by God or man.) Ah, those were the days, may they return swiftly.
 
 
Jan 26, 2009
Orson Scott Card came up with categories of "life" for the Ender series. The definitions are amazingly appropriate in determining the value and intentions (true or assumed) of the life in question.

Ramen are strangers from another species (as paradoxically explained in Card's own terms) who are capable of communication and peaceful coexistence with Homo sapiens, though that does not guarantee they will pursue the latter.

Varelse (pronounced var-ELSS-uh[2]) are strangers from another species who are not able to communicate with us. They are true aliens, completely incapable of common ground with humanity.

Djur (translated as: "slavering beast"): are the monsters. "The dire beast that comes in the night with slavering jaws."

The reason that this hierarchy is given is that with a species designated as ramen, communication and compromise are viable alternatives to war, while if a species is designated as varelse, then we have a right to wage war on this species in self-defense. However, these definitions are open to interpretation.

Quara, one of the characters in the series, even goes so far as to state, "As far as I can tell, intelligence is intelligence. Varelse is just the term Valentine invented to mean Intelligence-that-we've-decided-to-kill, and ramen means Intelligence-that-we-haven't-decided-to-kill-yet."

(Definitions & explanations from Wikipedia: http://en.wikipedia.org/wiki/Concepts_in_the_Ender's_Game_series )

And, ultimately, as pointed out in the books - the definition and interpretation is ultimately dependent upon the person/organization doing the interpreting.
 
 
Jan 26, 2009
usually the posts are thoughtful and intelligent, i am disappointed by many of today's responses.

some of you think that babies are not learning first moments of life, and definitely not before birth.

that runs contrary to RESEARCH about babies recognizing mothers voice pre-birth.

that runs contrary to LOGIC about learning to walk and crawl and see. it doesn't happen all at once. try programming a computer for facial recognition. there is a lot of code required to be set before even the simplest tasks can be competently performed.

that doesn't mean writting that huge code base is not intelligent, its a learning curve with increasing returns, and it starts of very slowly.

0-----
besides this, there are some who want to believe that fetuses don't feel pain because they don't have nervous systems fully developed. i wonder if these are the same people who love plant studies about electromagnetic fields. plants have no neurons, yet people want to hug them.

we kill babies, but put metal spikes into trees to kill loggers and protect plant life. its insanity.

some of these definitions and logic paths need to be worked out before people vote or come up with laws. babies feel pain and learn.
000000000
past the baby issue, the capacity for learning is never gone from any creature. gene therapy could grow ANY organism an extra head, which could then grow a giraffe schlong, wings, and even consume the tiny part that was the original.

who is to say if that is continuation of life? introducing foreign DNA to terry shiavo could have made her win the olympics in 100m dash next time around.

like with star trek and the USA probe that combined with other !$%*!$%* to become greater than mankind, there is no way to write off life and its ability to learn.

its possible that your dog could be struck by some gamma rays and develop a neocortex which is both compact and more advanced that any humans. all this could happen in a matter of weeks. bull cows weigh hundreds of pounds yet run faster than the fastest human. as far as the limits of brain size and efficiency, humans are nothing special.

DNA could make your arms fall off and grow wings instead. they could make you grow into a t-rex for first 10 years of life and then have most of body die. the reason we have fingers instead of flippers is not from fingers growing out of hands, but webbing between fingers dying. interesting to think of what gene therapy could do for us. we could live as dogs for portion of life, and switch housing for our brain and spine whenever cancer in body got to bad.

a lot like the futuristic parasitic overlord creatures of Stargate/Star Trek Dax..

if the trouble with life is that healthy tissue crashes like a corrupt executable file after running a certain duration, the solution is to kill it and grow new life. the smell of babies is beyond healthy. they can live on empty calories and still look beautiful.
 
 
Jan 26, 2009
usually the posts are thoughtful and intelligent, i am disappointed by many of today's responses.

some of you think that babies are not learning first moments of life, and definitely not before birth.

that runs contrary to RESEARCH about babies recognizing mothers voice pre-birth.

that runs contrary to LOGIC about learning to walk and crawl and see. it doesn't happen all at once. try programming a computer for facial recognition. there is a lot of code required to be set before even the simplest tasks can be competently performed.

that doesn't mean writting that huge code base is not intelligent, its a learning curve with increasing returns, and it starts of very slowly.

0-----
besides this, there are some who want to believe that fetuses don't feel pain because they don't have nervous systems fully developed. i wonder if these are the same people who love plant studies about electromagnetic fields. plants have no neurons, yet people want to hug them.

we kill babies, but put metal spikes into trees to kill loggers and protect plant life. its insanity.

some of these definitions and logic paths need to be worked out before people vote or come up with laws. babies feel pain and learn.
000000000
past the baby issue, the capacity for learning is never gone from any creature. gene therapy could grow ANY organism an extra head, which could then grow a giraffe schlong, wings, and even consume the tiny part that was the original.

who is to say if that is continuation of life? introducing foreign DNA to terry shiavo could have made her win the olympics in 100m dash next time around.

like with star trek and the USA probe that combined with other !$%*!$%* to become greater than mankind, there is no way to write off life and its ability to learn.

its possible that your dog could be struck by some gamma rays and develop a neocortex which is both compact and more advanced that any humans. all this could happen in a matter of weeks. bull cows weigh hundreds of pounds yet run faster than the fastest human. as far as the limits of brain size and efficiency, humans are nothing special.

DNA could make your arms fall off and grow wings instead. they could make you grow into a t-rex for first 10 years of life and then have most of body die. the reason we have fingers instead of flippers is not from fingers growing out of hands, but webbing between fingers dying. interesting to think of what gene therapy could do for us. we could live as dogs for portion of life, and switch housing for our brain and spine whenever cancer in body got to bad.

a lot like the futuristic parasitic overlord creatures of Stargate/Star Trek Dax..

if the trouble with life is that healthy tissue crashes like a corrupt executable file after running a certain duration, the solution is to kill it and grow new life. the smell of babies is beyond healthy. they can live on empty calories and still look beautiful.
 
 
Jan 26, 2009
The definitions listed in Wikipedia seem Ok to me, whether you go with the "has some of these characteristics" version that I remember learning at school, or the slimmed down systematic one. The fact that there's no consensus reflects the fact that scientists like to disagree, and that the world is a whole lot more complicated than the language of definitions.

The ethical questions about life and death are TOTALLY separate. Start adapting scientific definitions to fit ethical debates and they just become inaccurate. The definitions you need to consider in the moral debate relate to "Quality of Life" and "Sanctity of Life" - and, whichever you decide is more important, you then have to define either what constitutes consciousness (the ability to appreciate a good QoL) or who gets a soul/divine origin (or something else that gives certain things inherent moral value or SoL).

Also, the learning and pain conditions are a huge loophole for AI. If you define pain as an inbuilt negative reaction to certain types of stimulus (or some other similar definition) it's no difficulty to build a robot that senses that stimulus, and learns from it as much as a human infant would.
 
 
-1 Rank Up Rank Down
Jan 26, 2009
There is a brainular problem such that the sufferer cannot retain any new information. Would that mean they are dead?
 
 
Jan 26, 2009
Sometimes I find it helpful to take a different viewpoint to help understand a problem.

To define life you should also define death. So at what point does something die. Do viruses die, if they're not alive how could they? Does lettuce die, if you harvest it does it not stop growing (imho pants just die slower then animals)? How do you kill an android, if it can just be repaired and its "AI" backed up and reloaded.

Maybe life should be defined as "Something that can be killed".

Class discuss. :)



 
 
Jan 26, 2009
The Turing Test
 
 
Jan 26, 2009
"How about defining life as any discreet entity with the following qualities"

Why is discretion required? Or did you perhaps mean "discrete"?
 
 
Jan 26, 2009
Anything capable of chasing down its own breakfast is alive, far as I'm concerned.
 
 
Jan 26, 2009
Comedian Mark Steel was talking to a guy...
"So you're anti abortion and pro hanging. So what age do you think we ought to kill them?"
The guy thought for a moment and replied " Errrrm eighteen?"
 
 
Jan 26, 2009
Why does the regression stop at conception? Doesn't an egg have the potential to become a human and feel pain? Yes, it needs a sperm cell - but likewise the embryo needs nutrition. Both have the potentials you require if something is added, and not otherwise.

You need another rule, methinks.
 
 
Jan 26, 2009
I think if we found lettuce or viruses on Mars, then it's safe to say that there is life. Maybe this argument is more about how to prove that something is conscious or not.
 
 
Jan 26, 2009
At conception? Pain and learning?

Maybe you're just doing some mild trolling, but it seems to me pretty unlikely that pain is felt by a zygote at conception, or that the zygote learns anything. Frankly, I'm a little skeptical that pain and learning occur even in a freshly delivered newborn; the two that I had seemed like pretty much a bundle of needs with no comprehension of anything for their first several weeks. You could argue that newborns respond to pain by screaming, but then, one of my kids responded to existence by screaming almost continuously for his first few months. He responded to waking up or being picked up or being put down or being changed or being ignored or being smiled at in precisely the same manner that he responded to getting blood drawn, or getting vaccinated: by screaming.

Oh, and another criticism of your definition is that finding life on Mars requires a definition of life in general, and I'm thinking all we could really find on Mars is some sort of scum clinging to the edge of some ice. I think that would still be VERY big news, even if the scum couldn't feel pain or learn.

I suspect that maybe you're conflating "life" with "things Scott Adams isn't ethically comfortable eating." I haven't really thought that through though (nor do I have enough data to say how improbable it is), but I'm just throwing it out there for consideration. ;-)
 
 
-2 Rank Up Rank Down
Jan 26, 2009
Scott - I don't believe you. If you'd thought for one second about stem cell research, abortion, et al, then you couldn't possibly be surprised that people disagree on what qualifies as life.
 
 
Jan 26, 2009
Scott,
Clearly you've limited yourself to a current definition of "intelligent life".
Like "ina" before me, I believe a correct more encompassing definition is when proteins, or similar chemical molecules reproduce continuing their characteristics for multiple generations. I'm tempted to add something about the ability to evolve but feel that's pushing the needed base complexity too far.
 
 
 
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