I was surprised to learn that there is no universally agreed definition of 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
Your definition is more like "sentience" than "life." A plant is clearly a life form. So is a bacterium, and probably a virus. Regarding abortion, there is no reason to think that a blastocyst can feel pain. A third trimester fetus presumably can. When does that change, and is it gradual, or is it a discrete event we can detect?

And how do we define "pain"? An android that is programmed to detect and recoil from harm is responding exactly the same as we do. Is that not pain? Pain is just a neuron telling us that something is wrong.
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Jan 26, 2009
I feel Life is more complicated than just learning and improvising on abilities.

It's a large system with infinitesimal possibilities: The notion of life comes from change. When different things happen and are perceived as a coherent whole. This is canonical to the number line in mathematics.

Few possibilities of the change allow the system to sense itself (through human beings/animals/what not). When the system sees itself by virtue of its changes, it appears as the world to us (we are the system).

We are part of the system and we are affected by the basis of it. This is why we are subject to its rules: light, gravity, calamities, chemical reactions, death.

As an indirect consequence of this system, the system has gained abilities to see patterns in its perceived observations, which is called intelligence. Now the system acts as a parallel whole. While slowly changing, it can lead to improvising itself. The other possibilities include being able to degrade itself.

We are but a small speck of consciousness/computation of this life. In this possibility that we live in, one of our signals is pain. Animals try to get away from this pain. Animals may try to manipulate the system to avoid the pain. Sometimes this drives our system to improvise itself.

Because the system has infinitesimal possibilities, there can be life without pain. It might be different from ours. It may be inefficient. Or it might just be ours, sans physical pain. I personally wish I'd live in the other one, because that would make things like hunger/death easier.
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Jan 26, 2009
Sounds more like a definition of consciousness than life.
Jan 26, 2009
I don't usually post twice in one day, but I realized that my first post (see below) really doesn't say everything that I meant.

Lettuce is alive, but that doesn't mean that it is the same as me or should enjoy the same legal rights. Your definition is perhaps the subset of life that should enjoy protection under the law. But you'd have to change it slightly. Call it organisms OF A SPECIES that is commonly accepted to feel pain and be capable of learning.

Of course, this will never be put into any American body of law. Not once legislators learn that it would prohibit killing pigs, thus preventing the existence of pork.
Jan 26, 2009
What is pain? Isn't it just a signal? What's the difference between that signal and any other signal?

There is a subjective perception that pain is a different kind of signal, but there is also a subjective perception of free will, consciousness, and one's own soul, none of which exist from an objective viewpoint. So, I think pain only exists as an expression of subjective experience. Objectively, it can be viewed as a signal that some bundle of neurons reacts to, causing a particular cascade of effects.

The trouble with defining "Life" is the same trouble you always get into trying to define an existing nebulous term after it's been used millions of times by millions of people, and you want the definition to fit what most of them meant. Good luck with that. One of science's key insights is that, contrary to human nature, it is generally clearer and better to define words *before* you use them.
Jan 26, 2009
It seems that instead of trying to make the problem simpler, you've actually made it more complicated. Instead of one vague word (life), we now have two (pain and learn). Your definition of life is going to be a function of how you define these two words.

For example, if you define pain as "response to a negative stimulus" then even a rock can said to be feel pain if it cracks when you hit it with a hammer. If you define it more accurately as "a nervous system response to a negative stimulus", you've now ruled out rocks. But you've ruled out fetuses too, and plenty of other things that don't have a well-developed nervous system (for whatever reason). You'll probably find its extremely difficult to define 'pain' without referencing the word 'life' in some way. Your definition has now become circular.

Like most things, being alive isn't a switch that gets flipped on when something reaches a certain point; its more of a continuum. Different people will draw the line at what constitutes 'life' at different points along it.
Jan 26, 2009
While I don't feel that this is a horrible definition for SENTIENCE I do agree it's not very good for life.

I feel that the ability to learn should be to a degree also replaceable with the ability to reason and create knew information from already existing knowledge, as plenty of smart and functional people may no longer be able to learn new information.

Of course the definition of "life" should include some sort of ability to metabolize, grow, and develop without hijacking a separate life form -- in this way viruses then are not alive as they cannot reproduce on their own but must invade a host and turn it into a virus factory.
Jan 26, 2009
The funny things is plants actually have rights in Switzerland (super-smart land). I believe that you are describing something other than "life" more like consciousness or intelligent life. To be considered living all you would have to be (in my opinion) is have the ability to grow or reproduce under ones own means. This takes out fetuses because they are not growing under their own means, not until that cord is cut.
Jan 26, 2009
"One !$%*!$ issue is that life would begin at conception by this definition."

What the hell are you talking about? A fetus at conception can not feel pain or learn. Now it may be able to feel pain shortly after conception, but definitely not at. And I'd also argue that a 3 month old fetus does not have the capacity to learn.

Also, Dilgal makes a great point and one I had also thought of immediately. I remember reading a story about a girl recently who couldn't feel physical pain. I suppose she could feel emotional pain, so your general "pain" could be used to describe her as "alive."
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Jan 26, 2009
I have been missing your philosotainment posts. I hope this means they may be returning.

I would argue that you're asking the wrong question, though. On its own, we base very few questions around whether something is alive or not. We have no problem stepping on bugs, pruning trees, or shooting pregnant bambis so we can gorge on their flesh. The question of what it means for something to be alive is interesting, but almost irrelevant.

The real question is consciousness. No matter how well I program my android, it will never be more than a stimulus-response machine with no ability to reflect on its own being.

But good luck coming up with a definition of what it means to be conscious.
Jan 26, 2009
"2. Potential to learn."

So much for Congress.
Jan 26, 2009
the blog does not like !$%*!$%*!$
Jan 26, 2009
If your goal is to exclude artificial intelligence from being granted rights normally accorded to living organisms, then shouldn't your definition simply exclude non-biological !$%*!$%*!
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Jan 26, 2009
It seems like there are two definitions of "alive" to worry about.

1: "alive" as in amoeba, virus, germ, fungus, etc.
2: "alive" as in human being - someone in a coma vs. a brain-dead person whose body is still meeting all definitions of alive(1) but who will never be sentient again.
Jan 26, 2009
"I don't think lettuce needs to be "alive" any more than my watch." --Scott Adams

Lettuce is alive because it grows by itself. Your definition lets out almost everything that is currently classified as alive. That is simply dumb.

That doesn't mean that I think that lettuce, or most living organisms, deserves the same legal rights that I have. Your definition may be the definition of something other than life.
Jan 26, 2009
I would use the ability to reproduce rather than feel pain for several reasons:

1. I would say plants and viruses are alive, and they may not feel pain but they do reproduce.
2. Androids will probably need the ability to feel pain - really it's just a damage notification and they'll need to be able to detect if they're on fire etc. They probably won't be able to reproduce because we wouldn't need them to.
3. Pain is difficult to define, I think reproduction is easier to define.
Jan 26, 2009
Why wouldn't we want an Android to feel pain? How else would it know if it was in a position/environment that was causing it damage? Or perhaps instead of pain, you want to just says has the ability to feel Anguish, but then you should Consider The Lobster: http://www.gourmet.com/magazine/2000s/2004/08/consider_the_lobster

And we don't even need to go as far up the evolutionary ladder as big tasty sea bugs, Plants have been observed to release chemical markers as a response to an insect attack that other plants detect and change their chemistry that makes them less likely to be nibbled on. How is that different from people trying to avoid what caused the screams of pain they hear from another hairless monkey?
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Jan 26, 2009
First off, what do you mean when you say life? It sounds to me like you're trying to define whether or not something has a soul. I don't think your definition does much for determining whether a scientist who observes some weird little self-replicating organic macro-molecule on Mars has discovered life or not. And I don't think it's a good idea to claim someone who has lost the ability to feel pain is therefor dead - especially if they can still look at you and say "I'm not dead, moron".

How about we agree that there can be separate definitions for whether something is technically alive (life) versus technically entitled to legal rights (personhood). Trying to fit both into a single definition isn't very useful to anyone.
Jan 26, 2009
How do you know lettuce can't feel pain?
Plants certainly learn to adapt to their environment (usually faster than animals).
Plants are people too! Plant rights now!

"I'm not a vegetarian because I love animals; I'm a vegetarian because I hate plants."
-A. Whitney Brown
Jan 26, 2009
Due to an unfortunate accident I am a quadriplegic who does not have the ability to create new memories. By your definition I am not alive. This places my family in an awkward position - should they hold the funeral now since I am no longer alive, or should they wait until I am dead?
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