Definition of Life

[yukonmuffin]

Quote by: James Bond One of the hardest parts about arguing either for or against abortion is determining just what life is and what life isn't. In my studies of science I have learned that all living things are composed of cells. This is very strange because in my biology course last winter I learned about viruses and the professor had said that viruses, even if they are autonomous, have DNA, and breed, are not life because they do not have cells. This is just about the only thing I'd say science is 100% wrong about, but as I say this I, myself, don't have a definition of life. What do you guys think? What constitutes life for you?

Generally RNA, not DNA (though I think there are some.)
They are not autonomous, they depend on host cells. a computer virus can't work without a computer, viruses can't work without a host.
Bacteria are usually autonomous, they can fend for themselves (just like people!)

Personally I don't think there is life until there is sober thought, witch is believed to happen near or when it's born.
A lot of people don't seem to have a problem pulling the plug on unrecoverable vegetable states, what makes unborns so different? Potential is not the answer, considering People waste potential humans by the trillions each day.

[GeminiBrian]

Quote by: barts To what end is a precise, universally-agreed, definition of life necessary? Is there something practical that depends on this elusive definition?

Going back to the most basic definition of 'life' in the biological sense, I was struck on reading Prof. Dawkins latest book by the eloquent way he describes the Carbon:14 method of determining the age of organic remains.

To paraphrase and simplify, he explains in some detail how the element carbon is continually absorbed by all living organisms whilst they are alive, as part of the continuous exchange between the organism and its environment. . . When the organism eventually dies, this exchange of carbon stops completely and suddenly, and the carbon locked into the organism starts to radioactively decay at a known rate.

By this means, an analysis of the material being tested will show fairly precisely how long the organism has been 'dead'... up to a period of some 5000+ years.

I would say, therefore, that we need no better 'absolute' distinction between life and non-life.

added - on second thoughts - this thread might not be where I intended to post this - there's a degree of overlap with the Morality thread. Either way, it might be of some use.

[Questatement]

Quote by: ItsDarts "Fetal Metabolism can't start on its own until the pancreas and liver are formed enough to secrete fluids, this doesn't happen until the 13th to 16th weeks.

All I know is that when I Google "zygote metabolism," I get gobs of scientific papers and studies. For instance.

Effect of culture from the zygote stage on the metabolism of glucose and glutamine by 2-cell embryos and blastocysts recovered from outbred or F1 hybrid female mice

[ItsDarts]

Quote by: Questatement All I know is that when I Google "zygote metabolism," I get gobs of scientific papers and studies. For instance. Effect of culture from the zygote stage on the metabolism of glucose and glutamine by 2-cell embryos and blastocysts recovered from outbred or F1 hybrid female mice

Even IF we accept this, it still doesn't address response to stimuli. Now, we have to dig further and note what the definition of Metabolism is...

"The chemical processes occurring within a living cell or organism that are necessary for the maintenance of life. In metabolism some substances are broken down to yield energy for vital processes while other substances, necessary for life, are synthesized."

The bold is describing your link regarding a 2 cell zygote, substances are broken down for vital processes (like cell division). The italicized describes what happens when you have a functioning pancreas, the ability to break down food necessary for life sustaining energy. Prior to the formation of the pancreas, the fetus is totally sustained through the mothers ability to breakdown food, it can't do it on its own, its still basically just a clump of cells.

Ignoring response to stimuli, we can all probably agree that a cell or a bunch of cells (of any kind) are living organisms. But if we draw the line at killing living organisms such as clumps of cells, then we can't kill anything containing cells which would prevent us from eating. So the line is drawn with humans (in abortion cases) at life that could have sustained itself if separated from its mother, prior to that its a clump of cells.

[Questatement]

Quote by: ItsDarts So the line is drawn with humans (in abortion cases) at life that could have sustained itself if separated from its mother, prior to that its a clump of cells.

But that cut-off point as measured by the number of weeks from conception is continually being reduced. How then do we categorize the many fetuses aborted during the last 36 years which could not sustain themselves at their 'age' when aborted, but could easily survive now based on better medical practices?

What about those fetuses being aborted today that could not survive outside the womb, but in ten or twenty years, could?

Ethically speaking, are advances in prenatal care really the key to when full human worth, so to speak, "kicks-in?"

What about when medical advances can keep us all 'alive' for many decades or centuries beyond the average age of death at present... even as bed-ridden vegetables... would or should we be required to assign full human worth and keep them alive as long as medically possible?

[Thanatos]

Quote by: Questatement But that cut-off point as measured by the number of weeks from conception is continually being reduced. How then do we categorize the many fetuses aborted during the last 36 years which could not sustain themselves at their 'age' when aborted, but could easily survive now based on better medical practices? What about those fetuses being aborted today that could not survive outside the womb, but in ten or twenty years, could? Ethically speaking, are advances in prenatal care really the key to when full human worth, so to speak, "kicks-in?" What about when medical advances can keep us all 'alive' for many decades or centuries beyond the average age of death at present... even as bed-ridden vegetables... would or should we be required to assign full human worth and keep them alive as long as medically possible?

If you could start with a sperm and an egg, combine them in vitro and grow the whole thing outside of the body what then? What happens when we can just make any old lump of organic matter into a viable fetus?

It's entirely plausible that some day we'll be able to take a couple of pounds of raw chicken and use nanotechnology to make it into a wonderful healthy human baby and if that doesn't screw with your head nothing will.

If you used human cells instead of bovine cells to grow a steak in the lab (they can make steaks already although by all reports the flavor is way off) would eating this vat-grown human tissue be the same as cannibalism?

If you threaten a human-level AI with a large magnet is it legally assault with a deadly weapon?

Technology really screws with morality. I'm too tired to go into detail but if you're not capable of flexibility you're going to find yourself backed into some really weird corners.

[Questatement]

Okay, then just address the past (and real) circumstances please.

[barts]

Quote by: Questatement Okay, then just address the past (and real) circumstances please.

Like "What about those fetuses being aborted today that could not survive outside the womb, but in ten or twenty years, could?"

[Questatement]

Quote by: barts Like "What about those fetuses being aborted today that could not survive outside the womb, but in ten or twenty years, could?"

Is ten or twenty years in the future the past? Sheesh.

Quote by: Quest But that cut-off point as measured by the number of weeks from conception is continually being reduced. How then do we categorize the many fetuses aborted during the last 36 years which could not sustain themselves at their 'age' when aborted, but could easily survive now based on better medical practices?

[Thanatos]

Quote by: Questatement Okay, then just address the past (and real) circumstances please.

I'm sorry, I thought I was agreeing with you.

The point is biology is probably not a good way to assign moral status. People aren't their genes; they're their minds. Aren't they?

[ItsDarts]

Quote by: Questatement Is ten or twenty years in the future the past? Sheesh.

Currently at 24 weeks, the fetus only has a 50% chance of living outside of the mother, but still "not autonomously". It needs machines and technology. Medical advances will never reach a fetus living autonomously outside of the womb at some earlier gestation period due to biological reasons, period. Ultimately, it is not up to you to decide or in particular, men to decide for a woman when she can abort a fetus, we only have some form of laws to regulate when abortions can take place to satisfy some preconceived notions of ethics, which I'm not against. A 12 week old fetus will never survive on its own outside the womb, it is not biologically capable.

I've supported my position with what *I* think are pretty clear definitions. I also understand that you being a theist, will probably never agree purely on religious reasons if nothing else. The only problem that I can see with that may be that theists don't have any rights to dictate their morals values on the rest of us and each individual should be allowed to choose what is right for him or her. Currently we have laws that allow abortions, some choose to have them, some choose not too, why can't it be left that way? I know you may think your god is the one true god, but so does every other religious theist with different god(s), so I can't see how religious views can fairly take precedent.

[izzy]

I think that, people should let no one tell you what life is about - because when it comes to things like this it is different for everyone. It's your life therefore you should define it. :)

[yukonmuffin]

Quote by: izzy I think that, people should let no one tell you what life is about - because when it comes to things like this it is different for everyone. It's your life therefore you should define it. :)

Is there an echo in here?