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Should Science Rethink the Definition of "Life"?
ambermichelle pointed out a story about the search for life on other planets, and the likelihood that it would be much different than what we find on Earth. With the increase of extremophile discovery in recent years perhaps it's time to reassess what the definition of "life" should be. "In November 2011, NASA launched its biggest, most ambitious mission to Mars. The $2.5 billion Mars Science Lab spacecraft will arrive in orbit around the Red Planet this August, releasing a lander that will use rockets to control a slow descent into the atmosphere. Equipped with a 'sky crane,' the lander will gently lower the one-ton Curiosity rover on the surface of Mars. Curiosity, which weighs five times more than any previous Martian rover, will perform an unprecedented battery of tests for three months as it scoops up soil from the floor of the 96-mile-wide Gale Crater. Its mission, NASA says, will be to 'assess whether Mars ever was, or is still today, an environment able to support microbial life.' For all the spectacular engineering that's gone into Curiosity, however, its goal is actually quite modest. When NASA says it wants to find out if Mars was ever suitable for life, they use a very circumscribed version of the word. They are looking for signs of liquid water, which all living things on Earth need. They are looking for organic carbon, which life on Earth produces and, in some cases, can feed on to survive. In other words, they're looking on Mars for the sorts of conditions that support life on Earth. But there's no good reason to assume that all life has to be like the life we're familiar with. In 2007, a board of scientists appointed by the National Academies of Science decided they couldn't rule out the possibility that life might be able to exist without water or carbon. If such weird life on Mars exists, Curiosity will probably miss it."
If you know anything about TV science fiction, then you would know that all sapient life forms look like white people with maybe some ridges on their forehead or something (and they speak English). All flora looks just like what you find in California. And animals look like shambling people in horribly fake costumes.
Life is defined as something that feeds and reproduces.
The requirement for water or carbon is not part of the definition, it's simply properties we thought all life forms had.
FTA: Simply, Life is "self-reproduction with variations" - like mutating computer viruses?
Sure, life in the universe COULD be different than our carbon-based, water-needing forms. But there are restrictions on how many detectors etc. you can package on one rover. Given that difficult decisions need to be made in regards to equipping our search for life, it makes sense to search for life in a form that we are 100% sure exists at least one place in the universe.
Overly inclusive perhaps, but life could generally be defined as the ability to actively resist entropy (maintain low entropy) coupled with a method of passing that ability along. You could say that crystal structure represent a low entropy state, but they have no method to actively propagate it or pass it along other than growing. Throw out counter arguments at will, but I say it's pretty good.
I am always depressed about the primitivity of human thought, when I hear people discuss "Is this alive, or is it dead?". As if that was some binary either/or question or switch.
We have to face, that for every step between completely dead and whatever we define as completely alive, there exists something that fits that. And why wouldn't there?
Then we can rethink our egocentrism, and accept that we are neither special nor unique, and that that is OK. :)
It really is.
Life has to follow the constraints that we defined it to have, and therefore logically is between some bounds. E.g. the elements it uses, if it needs water, what temperatures it requires, what processes it uses and consists of....
But really it's just a definition thing. And nothing else. Since "life" is just a word. Nature itself does not know the concept of a "concept".
So I see this from a relaxed point of view. All this bickering about definitions and "ME, ME, ME, ME, ME, ME!" doesn't matter.
What matters, is that we are on the brink of discovering things on other planets... Things that can be so vastly different from ourselves, that our knowledge may leapfrog forward... And that yet may be so very similar to us in so many aspects, that is will tell us things about ourselves we could never have imagined.
Exciting times, baby. Exciting times indeed.
For any reasonably concise definition of life, it's possible to come up with a hypothetical example that clearly shows the definition is wrong.
IF we're going to find any life on Mars, it's probably going to be the carbon stuff we've been hearing so much about. Silicon life and other sorts of voodoo biology might exist in stranger environments but Mars is basically a big dry dust-ball sitting next to a big wet swamp-ball. Odds are that whatever splashed our planet in the first place also got Mars, and Mars just so happened to be tinier, lighter and colder than us enough that its water cycle kind of evaporated. Or at least that's the theory they're testing more or less.
Nobody is going to get funding to put expensive probing equipment on an expensive robot to prove a theory that life exists in a form that it doesn't exist in on Earth, and in a form that nobody seems able to create for testing purposes.
Life is anything that dies when you stomp on it.
Or, my personal favorite: Life is a monosyllabic morpheme consisting of a fronting diphthong followed by a labio-dental voiceless fricative.
On my planet, 'replicating' involves producing identical offspring (or nearly so.) If your method of reproduction involves a continual reduction in mass, we may need to rethink how the dictionary works.
In all seriousness, though, the definition of 'life' taught to young scientists doesn't proscribe any particular construction materials; hence this article (or at least this summary) is deceptive. The requirements are:
1. Homeostasis. It must make a detectable effort to maintain the conditions of its internals, and to adjust to changes in its environment.
2. Reproduction. It must be capable of creating copies of itself (or approximate copies of itself.)
3. Evolution. Its offspring must be able to adapt to changes in the environment through to natural selection.
That being said, there are circumstances in which some of these are suspended, like ancient trees and soldier ants that can't reproduce but are most definitely alive. The maintenance of an internal environment (homeostasis) is considered the most important, and the primary reason scientists have hesitated to consider transposons and viruses to be alive, even though they can reproduce and evolve.
Outside of these guiding principles, though, biologists really have no problem with the Enterprise running into plasma filament creatures, or Doctor Chaotica's henchmen duking it out with photonic life forms (although physicists might.) We're very good at pointing out flaws with some of these ideas (like "silicon is extremely bad at supporting life when compared with carbon") but that doesn't mean chemical evolution will never find a way to do it anyway.
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We don't assume something just because we can't rule it out completely, we assume something because there are signs indicating it's true. We have pretty good proof that shows that carbon-based life can exist, but there is neither physical nor theoretical proof of other exotic lifeforms. Not being able to rule it out is not enough reason to send another expensive probe when that money could finance far more promising research.
Actually, a rock falling and breaking IS evolution. Evolution simply means change. What it is not is genetic replication.
When our name is on the back of your car, we're behind you all the way!
Perfect replication + deliberate error mechanisms = evolution. Evolution has a tolerance rate; too many mutations too quickly and your evolutionary magic turns into lethal dysfunction. The rate of evolution for E. coli, for example, is a few orders of magnitude smaller than 1/(the number of nucleotides), which means that most of the time the offspring are a perfect match. Relatedly, humans manifest a substantial number of new point mutations when the gametes are formed, but have a much lower rate when producing somatic cells through mitosis. It's replication with a very small p-value. The article discusses the thermodynamic inevitability of mutation, if you're genuinely interested.
Bio questions? Ask me to start a Q&A journal. Computer analogies available for most topics!
Unless they're brutal, bloodthirsty warriors with some primitive sense of honor. Then they resemble black people with maybe some ridges on their forehead or something.
There are two kinds of people: 1) those who start arrays with one and 1) those who start them with zero.
Why would we care? We have a hard enough time communicating and getting along with those beings who we share 99.9999% of the same DNA with. Imagine trying to talk to some blob of silicon that is trying to say hello with ionizing radiation.
You have to be able to define life before you can redefine it. Turns out to be pretty tricky.
The Kruger Dunning explains most post on
They are looking for organic carbon, which life on Earth produces and, in some cases, can feed on to survive.
This is likely to trigger red flags in the minds of a lot of people with biological training. Just what is "organic carbon"? That's a media phrase that isn't too well defined in scientific circles. There's a great variety in the "organic" carbon chemistry of our world. But we should expect that any life on other worlds, even if it uses carbon, will produce compounds and radicals that are different and/or more varied than what we see here.
Another problem is that astronomers long ago pointed out a probable path for Earth bacteria colonizing the rest of our solar system, and possibly beyond. Earth has a thin "dust tail" produced by the same solar light pressure that produces comet tails. This is a problem for some kinds of astronomical observations in the plane of the solar system, since our dust tail reflects back back to us. Anyway, back in the 1970s, satellite and upper-atmosphere probes verified the presence of both fine dust particles and bacterial spores at all altitudes. The planet's dust tail thus contains such dust and spores. So the Earth has been contaminating the outer solar system with bacterial spores, presumably for some billions of years. We don't know whether any of those bacteria can survive on the outer planets. But the default assumption should be that some of them have, and have adapted to some degree over those billions of years to their new environments. Maybe they have; maybe they haven't. But if we find Earth-like bacteria out there, they probably came from here.
Some astronomers have also calculated out that part of our dust tail (and comets' tails) escapes the solar system. So we've been contaminating the galaxy with bacterial spores for billions of years. A billion years is around 4 or 5 orbits of the galaxy, up to 20 or so orbits since life arose here. The chaotic nature of galactic dynamics mean that our dust has spread through the entire galaxy, as has the dust from other planets with atmospheres.
This argument is more often used by the "panspermia" supporters, who point out that life from anywhere else in the galaxy could have colonized Earth in its early years, since the galaxy is around 13 billion years old, while our solar system is only about 1/3 that age. But some astronomers use it to explain how earthly life could have colonized the rest of the galaxy before humans evolved here. And, of course, both could be true.
Of course, the main problem with all this is that we have no data on how well bacterial spores can survive the millennia in interstellar space. Probably not well, but it doesn't take a whole ecosystem to establish a colony. For bacteria, it only requires one spore (and hundreds of millions of years ;-).
Probably the best prediction is that eventually, some probe will find a few bacteria on Mars and/or other planets, and they'll be somewhat similar to bacteria on our planet. This will raise more questions than it answers, as is common in most scientific fields.
Those who do study history are doomed to stand helplessly by while everyone else repeats it.
Two choices:
A) We can look for the sort of life we understand the best, with sensors that are very good at doing that, in places which are likely to harbor such life.
B) We can look throughout the universe for something completely unknown. We have no criteria to define it, no instruments to detect it, no idea where to look for it, and no way to interpret it.
Which of these two choices is the more feasible for a small unmanned probe?
James Lovelock came up with a perfectly good definition that doesn't stipulate any specific chemistry - he merely stated that life is that which will actively sustain a dynamic equilibrium when the non-living parts of the system passively change*. (He also argued that the distinction between living and non-living was stupid anyway, since there are too many inter-dependencies to make such a distinction in a productive way. Since his work forms the backbone of almost all modern life science, it seems pointless NASA resorting to definitions of "life" that have been considered obsolete for a decade or more.)
Indeed, Lovelock's theories on life are exceptionally useful to astronomers, because you CAN monitor the chemistry of the atmosphere of an exoplanet and you CAN monitor things like the solar radiation it gets. You can therefore utilize Lovelock's work to determine if the planet has life on it or not, remotely, without any regard whatsoever to the chemistry of that life or the mechanisms it utilizes.
*The basis of Lovelock's definition is that all life MUST geo-engineer. It has to, with no exceptions. That goes for viruses, bacteria, algae, etc. Not only must it geo-engineer, but in order for a system to be in dynamic equilibrium, the geo-engineering HAS to contain a negative feedback loop. The mere presence of life will alter the planet, but if it were to alter it without creating a dynamic equilibrium it would necessarily create a positive feedback loop that would destroy itself. In his view, you cannot treat the geology, the meteorology and the biochemistry as distinct fields - they interact and compartmentalizing will never let you understand the processes going on.
Analyzing soil samples will help on Mars but really it shouldn't be necessary. Dormant's another matter. If life exists in an active form, there will be variables that are held to a value and do not passively fluctuate with the seasons. If life *ever* existed on the planet, then the chemistry of the rocks will show that variables were held to a specific value and did not fluctuate with the seasons. The geology will record the feedback processes that all life (in this model) must have. The soil samples would let you identify what that life was/is, and to understand HOW it operated, but to merely detect if it was there to begin with you need look no further than the chemistry of the sedimentary rock we already know exists on Mars.
That is, if his theory is correct.
Evidently, despite the views of the life sciences, NASA is not following this path. Ergo, NASA thinks that despite the fact that it doesn't know what to look for, it shouldn't look where Lovelock said. I would hope they have a really good reason -- it's exceptionally bad science to ignore the prevailing theory, particularly if you have none of your own. They have to be rejecting his theory because if they accepted it then they wouldn't need to care about carbon, water, etc. They'd merely need to care about whether the chemistry could or could not be explained by passive processes alone. What the process was would simply not matter.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Actually, theoretically, the definition of 'alive' is disputed, because some scientists want viruses to be 'alive' and some don't. (Among many other disputes as to what the formal definition should be).
"Who is the Journal of Quantum Physics going to believe?" --Stephen Hawking
Fire.
Software.
What about clearly living things that can not replicate? such as a mule.
for the record:
Corwin was a whiny bitch.
The Kruger Dunning explains most post on
measured in bit seconds of locally retained information
divided by bit seconds of locally retained information expected (statistically) given the thermodynamic regime.
More (locally retained information retained longer) is better (more lifelike, or higher life, or what have you.)
That's my proposal for the definition of life.
Where are we going and why are we in a handbasket?
Science is about what we can detect and measure. It doesn't matter if you change the definition of life unless you can build an instrument that detects life with the new criteria.
1. Homeostasis. It must make a detectable effort to maintain the conditions of its internals, and to adjust to changes in its environment.
2. Reproduction. It must be capable of creating copies of itself (or approximate copies of itself.)
3. Evolution. Its offspring must be able to adapt to changes in the environment through to natural selection.
I'm not a biologist but I enjoy learning so I have a some questions about these definitions.
What's the current thought on virus? Are they 'living'?
Concerning #2. Shouldn't life have to create approximate copies? If they create [exact] copies, wouldn't that negate #3?
Concerning #3, If life doesn't make exact copies, doesn't evolution have to happen by way of natural selection. In other words are #2 and #3 redundant?
We classify viruses in the same way we classify living organisms, but there's still a lot of debate about whether or not they're alive. I could come up with a half-baked underslept computer analogy, but just going to Wikipedia would probably be more useful.
Regarding #2: a truly reliable and perfect form of biological reproduction is asymptotically impossible due to thermodynamics (this is mentioned in the article.) Assuming 'nearly perfect' = 'perfect', I meant 'approximate' to refer to complex mechanics like sexual reproduction, where the traits of multiple parents are mixed, and random evolution is enhanced.
Regarding #3: It means the organisms produced by mutation must be sufficiently different for natural selection to act upon them. A photocopy machine operating repeatedly in the absence of humans will produce imperfect copies, but no one cares.
Bio questions? Ask me to start a Q&A journal. Computer analogies available for most topics!
There are always exceptions to everything. Science isn't about what happens all the time, it's about what happens 95% of the time and hoping that we're right. For all we know, our definition of "gravity" is wrong and it has nothing to do with actual mass but something else that we can't detect that generally corresponds with mass.
Essentially, what we're arguing is semantics. When we say "life" we can't even be sure what we're talking about without using a sentence to specify. We could be talking about any number of normal scientific definitions or we could be talking about something that is equitable or superior to us without being anything like us. Take Data from Star Trek for instance. He wouldn't really fit into any of our definitions of life except that we can be fairly certain that he can reproduce (without material transference) and that he can think. Even then, his reproduction is shoddy at best. However, I don't think that's a problem. I think if such a being did exist, even without the ability to reproduce, he would still be considered life because of his ability to think.
I think that the parent post was right, the ability to maintain itself is the primary sign of life. And in the instance you describe, fire is not "moving" as we know it. The fire itself isn't actually moving so much as creating more fire in a direction. The only reason to consider your statement is if we can reasonably posit that life can consist purely for energy.
The more I think about it, I feel we're going to have to come up with a "vague" definition of life. Perhaps it would be more appropriate to say that it's alive if it is capable of any of a number of qualities.
Well, that's what I get for oversimplifying things for the Slashdot audience and not remembering lectures verbatim from four years ago. But you may want to take your ad hominems out back and shoot them: the Wikipedia page is somewhat more thorough, and includes organization, which is the critical quality that rules out fire. To be living, an organism must do all of these things (evolve, adapt, reproduce, respond to stimuli, and maintain its internal environment) through orderly, controlled means. In standard organic Terran terms, that means metabolic chemical pathways.
And for your information, the exceptions I listed aren't exactly classic exceptions. The question of whether viruses constitute life is under debate, and sterile organisms are essentially modifications of other members of their species, which are very much capable of reproduction.
Finally, the definition is supposed to be used to differentiate large groups of phenomena from life, and has widely been recognized as inexhaustive and incomplete for a long period of time. You expect too much of experimental science if you believe that a scientific definition must be so rigourous.
Bio questions? Ask me to start a Q&A journal. Computer analogies available for most topics!
If we focus on planets in "the habitable zone," then life is much more likely to be based on C, N, O, etc. than something more exotic (to us) because that's likely to be the prevailing chemistry able to generate "self-reproduction with variations." Many of the other alternatives with Si, liquid methane, or other weirdness is unknown to us because such chemistry is extreme within the context of the habitable zone. Next questions: Is Mars in the habitable zone? Is there enough water, atmosphere, background energy, and other conditions needed to generate sufficient quantity and turnover of organic compounds to sustain self-reproduction with variations?
I think this is actually a physical chemistry talking point, so don't feel too bad. :) When a chemical reaction occurs, very rarely is it an instant on/off thing caused during a single, instantaneous collision. Most reactions take a number of steps, each of which has a certain probability of occurring. Misreactions also have a small probability of occurring, albeit generally lower; in organic chemistry every reaction has a percent yield and needs purification afterward (an imperfect process.) Because of all this, reaction as complex as a biological enzyme binding, modifying, and then releasing its substrate can take many, many attempts (I don't have the magnitude on hand, but you can bet it's many times larger than a billion molecular vibrations) before it occurs, and is never perfect. To make things worse, the reproduction of DNA requires multiple enzyme reaction steps per nucleotide, and one of the steps is responsible for verifying that the nucleotide being inserted is correct. There are additional steps on top of things that try to do proofreading, but since everything is error-prone, the whole process can, ultimately, fail.
Bio questions? Ask me to start a Q&A journal. Computer analogies available for most topics!
How we define "life" when searching the cosmos is entertaining, but to me the bigger philosophical question to consider is alien sentience (not just intelligence) -- self willed, thinking, rational or irrational beings who think, feel, and act for themselves similar to us, but likely following completely different structures of society and morality.
I do not fail; I succeed at finding out what does not work.
There's nothing deliberate about the error mechanisms that cause mutation and therefore make evolution possible. "Deliberate" is the kind of word that's more appropriate to discussions of "intelligent design" than evolution.
The error mechanisms exist and are arguably necessary, but in the world of chemistry, randomness is everywhere so you don't need to go looking for deliberate errors.
But parasites, even internal ones that rely on the environment of their host bodies to reproduce, take in food and process it into new parasites internally. For a virus, everything that could be considered a life process is outsourced to the host. A virus, at least by a classical textbook understanding (although I distrust those because they're always oversimplified), doesn't have any life processes of its own. It doesn't aquire food or process it to grow/heal/regenerate, or to make more viruses. It doesn't process energy to move itself around (although, this is one of those oversimplified things, since viruses do have all kinds of adaptations for making use of their environment to get to where they need to go) or for anything really. It's basically just floating around, lifeless until it's attached itself to the DNA of a living cell, at which point it hijacks the cells own life processes to make copies of itself.
Of course, that said, viruses, or at least virus-like entities almost certainly predate actual cellular life. It's hard to say exactly how they existed and replicated at that time. With mechanisms that are unnecessary today because of their parasitic existence probably. It's likely that once more complex life came along, they couldn't compete on gathering the resources to survive, but they could still "live" a zero-energy "lifestyle" between parasitic reproductions. For all we know, there could actually be thriving populations of virus-like organisms out there that gather resources to reproduce themselves and fully meet pretty much all the definitions of life, but it's unlikely we'd even notice them if they don't infect cells and that's what would draw our attention to them in the first place
All that said, I'm not sure that I buy that viruses aren't alive. Or rather, I don't buy that there's such a bright line between alive and not alive. If a person dies. We can usually be very clear on whether or not they're dead if their heart has been stopped for an hour or so. But, at that point, provided the death didn't come from something extraordinary, pretty much every single cell in the person's body is still alive. The biotech industry makes a lot of use of CHO cells, which are a strain of chinese hamster ovary cells which self replicate indefinitely. The original hamster is long dead, but cells derived from it live on as a single celled organism that can survive on its own in the right environmental niche (admittedly that environmental niche pretty much needs to be a sterile, nutrient filled bioreactor built by humans). Some vertebrates regularly survive being frozen completely solid, with all life processes stopping, and then they thaw and are alive again. Basically, the whole life thing is a lot more complicated than alive/not alive and viruses really fall a lot more into the life category than the unalive category.
... a labio-dental voiceless fricative.
I don't know why, but I feel a little dirty after reading that.... Is that, like, Latin porn or something?
Crumb's Corollary: Never bring a knife to a bun fight.
Well, not the first stomp...
After calming me down with some orange slices and some fetal spooning, E.T. revealed to me his singular purpose.
Science doesn't have a definition of life to rethink. The best we have come up with is: "Living organisms undergo metabolism, maintain homeostasis, possess a capacity to grow, respond to stimuli, reproduce and, through natural selection, adapt to their environment in successive generations. More complex living organisms can communicate through various means.[1][5] A diverse array of living organisms (life forms) can be found in the biosphere on Earth, and the properties common to these organisms—plants, animals, fungi, protists, archaea, and bacteria—are a carbon- and water-based cellular form with complex organization and heritable genetic information." (wikipedia)
This is not a definition. It doesn't even claim that all conceivable or possible things that have these properties are life, and I would not discount the possibility of finding something that did not have one of these properties that still seems worthy of calling life. Maybe science should change its definition of asjkdhljkfg while we are at it. The 'definition' doesn't even say that life is carbon based or water based as the summary seems to suggest, rather it goes out of its way to stress that this is just true for what we have seen so far.
If you substitute the term "life" for something like "Earth-like life," all of the quibbling goes away. There absolutely, certainly could somewhere be life that is not at all like the life we know of on Earth, but we have no idea what that would look like or how to detect it for the first time, so it makes no sense to look for it right now. We know what life on Earth looks like, and how to recognize it (or the conditions that it requires and in which it is found everywhere on Earth), so it doesn't make sense, at this moment, to look for anything else, or not to look for conditions that favor Earth-like life. Hopefully someday we'll be cognizant of non carbon-based life forms, or life that does not rely on water (or watery conditions that for whatever reason do not support life), but for now they're doing things right and acting prudently rather than wasting precious resources on wild goose chases.
This is a hacked account, for which the owner can not be held responsible.
To a biologist, "evolution" refers to the Darwinian variety. Basically, that means reprodcvtion with heriditable variation. On that basis, I consider viruses to be life, but not rocks
Oh, that's your own fault... You should have put it in neutral. If only more people would neuter their cars, we wouldn't have the problems we have today with feral cars! Why don't people THINK!
Did you lose an alveolar lateral approximant somewhere on the way?
Ubi solitudinem faciunt, pacem appellant.
I need coffee right now but I don't think I've enough evolution to buy one.
I know the truth and I know what you're thinking
If their heritable mutation affects their probability of reproduction, so that it is capable of evolving in a Darwinian fashion. There is a theory that the earliest form of life might have been crystalline.
If your computer reproduces, and has heritable mutations that affect reproductive success, so that it is subject to Darwinian evolution, then I would consider it to be life, whatever the its form or behavior.
The answer to the question, "what makes us humans different from animals?" is of course "nothing," because we are animals. If you mean, "what makes us different from other species of animals?," the answer is different genes.
If you ask, "what about our behavior is different from other animals?" there is a long list, although some of the answers are quantitative rather than qualitative. However, I doubt that it is meaningful to talk about "taking culture away." Culture likely co-evolved with our biology and is closely linked to biology. So this is a bit like asking, "what would make humans different from other animals if we weren't humans?"
People like you make me fear for my unborn grandchildren. I see folks with no understanding of how computers work thinking that they're "thinking machines", like idiots in the media have been calling them since ENIAC, which was less powerful than a Hallmark greeting card.
A computer is nothing more than an electric abacus. It works on exactly the same principle as an abacus. IT DOES NOT THINK, IT IS NOT ALIVE! I made a pseudoautonomous program thirty years ago on a machine with only 16k of memory and no disk drive. You'd have sworn it could think, but I assure you it's only David Copperfield trickery, not Merlin Magic.
But you people will have a "machine rights" movement anyway, if history is any indication.
However, I do tend to think that we might find life, even intelligent life, and not realise it's alive.
If we took all the culture/religion and all the technology away , what makes US humans different from animals?
We are animals. We're not different from animals, we're different from other animals. I'm sure bonobos think they're life's superiors and consider us less than bonoban, and probably dolphins as well (Douglas Adams comes to mind here).
If you would replace many of your organs with inorganic components and you weren't capable of reproduction through SEX , would you still consider yourself life?
I'm a cyborg, and although I can reproduce I wouldn't be able to if I were female, because I'd be past menopause. I do know post-menopausal female cyborgs, and yes, they're human as well as alive; their cells still reproduce. Are you trying to say that a eunuch isn't alive? That's just silly.
Many life forms don't reproduce through sex, but they do reproduce. Asexual reproduction doesn't mean an organism isn't alive.
I don't really care what the definition of life is because it surely is WRONG.
Words are defined by consensus. "Life" is whatever we say it is.
Free Martian Whores!