A key "culprit" is the Twin earth experiment. Some people already think "Internalism" versus "Externalism" is a non issue which adds to its problems. But alot of the premises in the experiment are dubious such as someone on Twin Earth having identical mental states despite the human body consisting of a lot of water (H20) which means Twin humans body would consist largley of XYZ making any identical states implausible. — Andrew4Handel

Agree, it is implausible, but still immaterial (pun intended) to the point of the experiment. So what if the twin Earth were antimatter? Now the chemistry is identical, and so are the mental states. The thought experiment now is valid, even after each side discovers the atomic structure of water.

Also I have mentioned a problem with counterfactuals so in this case, and others, the existence of these planets (or aliens) is highly unlikely or non existent.

It seems that the existence of a twin Earth (real water, not XYZ) is a certainty given that there is only a finite set of states of matter in a finite space (a Hubble Sphere for instance), and that space is infinite. Max Tegmark computed an upper limit to the distance to the nearest such twin, but elimination of unnatural states (aluminum cube planets, humans with memory of a different sky than what they see) puts the actual distance much closer.

Finally, what requirement is there for the plausibility of a thought-experiment if the implausible part does not interfere with the point? If there was no Prof Knut Nordby, would the Mary's Room thought-experiment be less valid? Such thought experiments seem the only way to explore subjectivity.

Define inanimate. What is its essence? :) — apokrisis

Not animate. Duhhh...

It doesn't in any direct way. We got side tracked by you claiming that the essence of A and B must exist for the law of non-contradiction to be applicable. I refute this by claiming that we only need consistency and not essence for it. If we agree to this, then my first premise in the argument to prove that essences exist stands: "Either a being is a living being or a non-living being. It cannot be both." — Samuel Lacrampe

Let me try this logic out. Suppose I try to nail down the essence of 'cute'. I pick an arbitrary way to sort things into two heaps: A thing is cute if it masses more than a KG. So I am cute, but this pebble is not. There is at least one thing in each heap, therefore there must be an essence of cute. Somehow the proof seems invalid. Your 'bald' criteria (admittedly not the actual essence) is more a description of alopecia, not bald.

Maybe "circular" was the wrong word; my bad. Nevertheless, it sounds like you demand to know X in order to prove X using the law of non-contradiction.

That X exists, not that it is known. If it doesn't exist, then there is no definite is-life or not sorting, and your first premise fails. Not talking about our ability to know or not, but an actual indeterminate state of some thing being life or not. Without the essence, there is no fact of the matter, and no contradiction by something being in that questionable state.

I invoke Aristotle's theory of abstraction: We all have in ourselves the implicit knowledge of terms such as 'living' and 'non-living'. This is so by our years of sense observation of the world. — Samuel Lacrampe

And we have but one example from all our sense observation. Our implicit knowledge concerns only that one example. Intuitions will not serve us for the general case as we attempt to recognize the second example.

This implicit knowledge is what enables us to use the terms correctly in everyday language, even if we don't have the explicit definition of all the terms used. Thus a 10-year old can have a meaningful conversation without ever having read a dictionary. Finding the essence of terms is simply acquiring explicit knowledge based on our implicit knowledge. I think our implicit knowledge that a dog is living and a rock is non-living is pretty grounded.

Read the NASA link that Banno posted. Dr Cleland speaks speaks directly about this. We are unconcerned with the 'definition of life', which would be a description of how the word is used in our language, and by said 10-year-old. What we're seeking in this thread is what she calls a "scientific theory of life" which seeks to define a set of rules for the more general case. Common language usage is of zero importance to what NASA does.

I notice that in that article, no attempt is made to set out any rules or traits or other progression towards this essence.

I disagree. The only criteria is consistency in A and consistency in B in the law of non-contradiction. You don't need to find the real essence of "bald" but merely need a consistent definition, such as "no hair anywhere on the head". In this case, "I am bald" and "I am not bald" are mutually exclusive. Therefore only consistency and not the essence in the terms is needed to apply the law of non-contradiction. — Samuel Lacrampe

OK, you've selected that arbitrary criteria of which I spoke (not exactly since we've not defined where 'the head' stops, but let's define that as the smallest cross section of the neck, which works for humans at least). How does this arbitrary selection provide evidence that there is an actual essence of 'bald'? Never mind the fact that the criteria sorts all of humanity into the not-bald side, so the distinction must be pretty meaningless.

If no absolute criteria is known (fuzzy fact), then you can't invoke the law of contradiction to prove that there is in fact an absolute criteria.
— noAxioms
Your statement is circular.

How so?

Are you asking why finding the essence of life is important? I personally find the topic interesting; that is why I am here. Why are you here if you don't find the topic important?

Interesting yes, but the topic can be discussed without needing to know that there is or is not an actual 'essence'.

- There exists an instance where a being is clearly labelled as living and another instance where a being is clearly labelled non-living: e.g. a dog and a rock. — Samuel Lacrampe

About this one: No 'essence' (in quotes because I dislike applying the term here) has been established, so the example is not a clear one. There are those that have argued on these forums that rocks are an example of life, or that dogs are not. I may not agree with these positions, but I have no rule which I can apply to prove either of them wrong.

Furthermore, it seems like an easy cop out for someone to dismiss a logical argument simply on the grounds that he does not believe in the essence of the terms used. — Samuel Lacrampe

If there is no solid truth value to some proposition, it is not a logical (boolean) argument, but rather a fuzzy one. "I am bald" and "I am not bald" can both be true since there is no agreed upon theory of bald.

I think it still does due to premise 2. Here is an analogy: We know country X exists because we know someone from country X. We also know country Y exists because we know someone from country Y. This is enough to deduce that a separation or border exists between countries X and Y. — Samuel Lacrampe

What's this got to do with it? For one, the existence of a person who is "from" (born in? Raised? Citizen?) country X is not proof of the continued existence of X. Furthermore, the logic made no statement that all countries occupy disjoint geographical regions (and there are indeed counter examples), so no conclusion about their separation can be drawn at all.

My example was for one hard or fuzzy fact, like a person is from X, or a person is not from X. The law of contradiction can only be applied if there is an absolute (hard) criteria to determine "is from X", whether or not you want to invoke the word 'essence' in all that. If no absolute criteria is known (fuzzy fact), then you can't invoke the law of contradiction to prove that there is in fact an absolute criteria.

Why is it important? You've never answered that. Suppose we find something that most people agree is life. What then? Does it require a plaque? Does it become a crime to wipe it out (genocide), or interfere with it (prime directive)? There are no such obligations right now, so it isn't important, at least not yet.

Premise 1 is not based on the conclusion, but on the law of non-contradiction: the two propositions "A is B" and "A is not B" are mutually exclusive. This is known with certainty even if we don't know what A and B mean. — Samuel Lacrampe

We've been over this in prior posts. Law of non-contradiction does not hold without a hard definition of the essence, so invoking the law presupposes the conclusion that there is such an essence. Dr Cleland brings the subject up using 'bald' as the example.

Yes, one could arbitrarily make up such a rule, and then be able to classify anything as life or not-life, but what has that proven? That is not the essence of life, it is just an arbitrary rule that sorts things into two buckets. It does not prove the existence of an essence.

I see what you're saying, but your proof is circular:

This may be the end result. But at least I think I can prove that the essence of life exists:
- Either a being is a living being or a non-living being. It cannot be both. — Samuel Lacrampe

That postulate presupposes the conclusion. Any proof based on this is begging.

I mean that a dog is clearly labelled as a living thing, and a rock is clearly labelled as a non-living thing. You misunderstand the point. It is that there are things that fit in each label. — Samuel Lacrampe

You pick two easy ones. Pick something on the line like a biological virus and a computer virus that does random signature changes. The label is not so clear. If one is life and not the other, what makes that distinction besides the bias that the biological one is a 'closer relative to me'?

Yeah I admit I don't understand what the term "semiosis" means (process that involves signs?). — Samuel Lacrampe

There must be data which allows it to persist improvements made. Fire doesn't have that. Plenty of non-living things do, so the feature is not sufficient.

- Either a being is a living being or a non-living being. It cannot be both.

Cannot agree with it. The line is fuzzy, so something can be questionably on either side.

- There exists an instance where a being is clearly labelled as living and another instance where a being is clearly labelled non-living: e.g. a dog and a rock.

Don't understand this one. A rock is not a dead dog, and would a dog not qualify as life if I could not produce a dead one?
If you mean a dog is living compared to the rock, the label seems to have already been applied for the rule to have meaning, so it does not help narrow the essence you seek.

For any rule, it seems to take little effort to conceive of an exception. The conclusion seems to be a theory that avoids strict rules.

This:

https://www.nasa.gov/vision/universe/starsgalaxies/life%27s_working_definition.html

Especially the first question to Dr. Cleland. — Banno

Brief, but I like it. The author of the article (identified only as 'magazine staff') seems not to entirely understand the subject, giving this statement:
"For example, a crystal can grow, reach equilibrium, and even move in response to stimuli, but lacks what commonly would be thought of as a biological nervous system."
Lack of something serving as a nervous system is what disqualifies a crystal as life. Hmm...

Anyway, the article is about the theory of what life is, but only one question touches on that, the other ones being about the origins of the one example we know. Dr Cleland hits on many of the points discussed in this thread, and warns against any hard criteria to use in the identification of life since it seems pretty easy to come up with a counter-example of any rule. My favorite quote is her last one:
"Merely defining "life" in such a way that it incorporates one's favorite non-traditional "living" entity does not at all advance this project."
I think I have observed that. Several of us have tried to pinpoint an essence, and the attempts indeed seem not to have advanced the project. I notice Dr Cleland does not offer even a hint of a description of this scientific theory of life. We need one, but we don't have one, and probably cannot have one until we have several other examples under our belt. Our current same size of 1 is insufficient.

...In which she criticuzes the limitations of mere language as inadequate to the tasks of biologists. — Wayfarer

In which she criticizes the term 'definition' of life, as opposed to 'scientific theory' of life. Asking for a definition is not to ask what the thing is, but merely how the word is used in one particular language.
I need to remember that in other discussions.

characterised by the ability to metabolise nutrients, respond to stimuli, mature, reproduce, and adapt to the environment through semiosis. — Galuchat

This may answer my previous question. But would that not make a fire a living thing much like a cell? Note, this seems to be the position of some people in this discussion. I am on the edge on that one; and yet I cannot seem to find a clear difference between a cell and a fire. — Samuel Lacrampe

Fire seems not to meet the last one. I don't particularly agree with the list, since I can think of exceptions to the other four items, but semiosis alone seems not enough. I have bailed on attempting to define an essence, and leave it a call to be made on a case-by-case basis. Undoubtedly we will not always recognize life when encountered, and will classify some things as life that really shouldn't be.

Where do you look, in order to determine that metabolism and replication are necessary and sufficient for life?

Presumably, at things that are alive.

It follows that you already know which things are alive before you set out this posited essence. — Banno

This works fine when we have essentially one instance of life and everything that evolved from it. But as Bitter Crank pointed out, we cannot wield our common usage intuition when we go to Mars and decide if something is life. A formal set of guidelines would really help, but it also must be flexible. Such guidelines are probably not forthcoming until we have several examples to compare (as opposed to the one we know now) and we have a reasonable data set from which common traits might begin to stand out. Who knows, it might turn out that we don't qualify ourselves.

Life is the property of a living thing which distinguishes it as alive rather than not alive; if it has life it is alive. Would could you possibly mean by "the virus has life, but it is not alive"? That seems completely contradictory. — Metaphysician Undercover

Posted the difference earlier.

A dead cow in a field is an example of life, but is not alive. A live cow might still be created from one, but not the same cow. My clock is alive, but is not life. Alive just means the parts are currently operating (not broken, and not completely dormant). It is a fuzzy definition of 'alive', sure. You might choose to apply the term only to a life form (cow) that might be dead or alive, but the term seems to work for non-living things.

From this information, I see only two logically possibilities for the original cause:
1. random event from nature, despite the improbability
2. not-random event, that is, intelligent design — Samuel Lacrampe

Second one is disqualified, because if a particular instance is designed, it is not original cause.
I personally suspect Earth life originated elsewhere and fell from the cosmos, but that doesn't solve the problem, it just gives you a lot more diverse places and conditions where the original improbable dice roll came up lucky, and was perhaps more probable.

Is a virus alive then? — apokrisis

I differentiated the terms. I would have said the virus is life, but it is not alive since it has no functioning parts most of the time.
So a computer virus would be life, but not necessarily alive. A full self-contained machine-organism responsible for all aspects of maintenance and persistence I guess would be alive. Suppose we dropped such entities on a planet without biology, and they lost their original task and just evolved from there. They'd eventually evolve to wonder about their own origins and would consider it obvious that at some point a most basic form was a spontaneous accident.

I think the appropriate question is, could viruses replicate sans life? As far as I know the answer to that is 'no'. — Wayfarer

Humans also cannot replicate sans life. We have much more of the machinery of replication built into us, and are 'alive' in the sense that we function in some entropic way. But I am just as dependent on the external machinery (or at least the byproducts of it) as the virus. Apo did point out a clear distinction of dependence on the machinery itself vs us being dependent on the byproducts only.

A human can be both alive and suicidal at the same time; they're not mutually exclusive, which is the minor point I tried to make. — VagabondSpectre

Yes, and sterile as you point out. Defective examples of life are still life.

It has to do with the way the data is organized. The way data in the human brain is organized itself facilitates the mechanical extrapolation and development of consciousness. The way data contained in DNA is organized within the nucleus of a cell is what itself provides mechanical intelligent instruction to the rest of the cell.

I think 'intelligence' is about as fuzzy a term as 'life' or 'unnatural', 'intent' and 'consciousness' and we should avoid the terms. Apo has the right term. Semiotics is the difference between the data in DNA and the data in rocks.

Fire is not life, it's a chemical reaction we call combustion. It doesn't anticipate it's environment, it consumes it as fuel. It doesn't display intelligence or behave in a manner conducive to it's survival. It chaotically consumes what is available to it and then is extinguished in a predictable manner.

You just described humans. The difference seems again to be the semiotics. Yes, I agree that fire is not life.

Bacteria can swap genes (such as genes coding antibiotic resistance) between members of mixed species colonies.

This one is pretty cool, bordering on the benefit we get from sex.
Much of your list shows that it isn't entirely remarkable at all that multicellular life forms evolved.

And that is why a virus seems troubling. We can't really talk about it as an "it" because it is not self-sustaining in that minimal fashion. It is a bare message that hijacks other machinery. — apokrisis

I am also not self sustaining, hijacking the machinery of plants to harvest solar energy. Nothing is completely self-contained, so I don't see the issue with viruses. They have the semiotics and sufficient machinery to live off of their environment, which is other cellular life.

Likewise the computer virus seems to be life, living off the machinery, but not containing that machinery itself any more than I contain the machinery to photosynthesize. Fire on the other hand is not life. No semiotics that I can see.

The biologists have a pretty good definition, and it applies to non-biological forms.

Also, 'tall' should always be relative to X if we want to say something that is objective and accurate.

Now I agree that in an everyday conversation, people may say "He is tall" (with no relation). — Samuel Lacrampe

There must always be a relation to an X, and there is no objective X. It seems always contextual. In everyday conversation, "He is tall" references a context-dependent X. The relation is there, else the statement is meaningless. The X is indeed probably fuzzy, making it more also a function of opinion, but my point is that there is always an X, and X is not objective.

I am considered tall (probably over 80% of all humans, so there's one plausible X: a certain unstated percentile of height over some implied reference class), yet the pin-oak in my yard is twice my height and is not tall at all. Different context, so different X, both of them fuzzy in this case. I can't think of a non-fuzzy case where X is not explicitly stated.

Your title does not describe your OP, as Pneumenon points out. Why be moral? Because it's the right thing to do. It's that easy, and by definition.

As to the distinction between there being objective truth to any particular rule, there is none so long as there is no way to detect the rule. So it matters only if the nature of what you are is of the sort that can be held accountable in some objective way to said rule, and if the rule is conveyed in some way.

As an example, suppose the universe consists of integer math expressions, and the objective morality is to have an even number result. 1+3 is moral, but 8-5 is not. Is there a distinction that makes a difference to those equations? Well, it matters only if 1+3 has objective existence outside my universe set (I can remove it from the universe and consign it to a good or bad place, and it would care about this), and if the fact of the immorality of an odd result is conveyed to them while still in the expression universe (how would either know?), and if those equations have the free will to alter their result. The physicalist denies all three, and the theist claims all three. 8-5 was conveyed the morality in question, and is given the free will to let 8-5=4 against its physical nature, thus earning its way into the good place after 8-5 is removed from the expression-universe. The distinction is there, but not in this universe.

As for killing babies, the example is skewed by argument from emotion. Pick something less clouded by emotion to look for truth. It is easy to argue for the morality of killing babies if you can get past the emotional implications. There are plenty of species that are fit partly because they do exactly that.

I'm just pointing out that the intention to procreate or go on living is not present in all examples of life. These examples of life die, but they continue to crop up. — VagabondSpectre

The elimination of unfit members is natural selection in action. The species itself would die out if suicide was a general trait. My definition of life included persistence, so I have to disagree. Humanity as a whole is something that tends to persist. Humanity is an example of life. I also don't think there is intention involved, but you're free to apply that word to what a tulip does.

By "perpetuate" do you mean "reproduce/procreate"? — VagabondSpectre

No. If it can perpetuate without procreation (just be sufficiently immortal), it can be life. Perhaps creation of competitors is not in its best interest. Procreation is just one way to achieve this, and it is a far more efficient way to speed evolution, so that method tends to get selected over the more evolution-resistant method of immortality. It is harder (but certainly not impossible) to make improvements to an individual than to a species.
Yes, life tends to die. Something that is immortal needs a mechanism to ensure survival from major accidents, which are inevitable. There can be no single points of failure.

Rocks are hardly sensitive instruments, let's be honest. And they don't often find themselves organized in a structure where data can be readily recorded and then retrieved using them as a base unit. — VagabondSpectre

They do record data readily. How else do we know the long term history of the planet? Ask the rocks. The information is stored nowhere else it seems. Their lack of USB port to download the information just means you need to learn their language if you want them to talk to you.

Complexity is most certainly relevant to life. Can you fathom any form of life, real or hypothetical, whose internal workings could not be described as "complex"? — VagabondSpectre

We have not defined life. Banno says fire meets the requirement, and since 'unnatural' was found to not belong in my definition, I think fire is life, just a very trivial form. So there's the example of one not complex, and that lack of complexity is why most don't consider it life. If you don't agree, I think the claim of a requirement for a certain level of complexity needs to be defended.
Fire doesn't seem to partake in natural selection, but nobody has listed that as a requirement. "Sufficient complexity to support natural selection"? That would add the need for data, which your definition had, and mine did not, and which fire seems not to have.
I don't like the word 'intent'. I think bacteria intends to persist no more than does fire.

And yet a small percentage of Pandas may survive, and they may be forced to start living on more diverse diets. The genetic data resulting from the long history of panda ancestors eating other things will surely benefit them as they transition into alternative diets over individual lifetimes and over generations. — VagabondSpectre

The panda is sufficiently perfected for its niche that adaptability is all but gone. It cannot transition faster than its environment is changing, and will likely only stick around in captivity as do so many other sufficiently cute creatures. Possibly not, since they don't seem to thrive well in captivity. A bird of paradise has the same problem.

I'm using the term organism in a particular sense; an organ (read: organized). A defined system of interacting and inter-dependent parts that cohere to form a whole (a defined boundary, not necessarily a full internal model) — VagabondSpectre

OK. Is a computer virus an organism? Are there really 'parts' to it? I guess there are, just like there are parts to DNA that serve different function.
The only difference between a computer virus and a biological one is that the former is known to be an intelligently designed thing. That suggests that biological primitives might be as well. Biology seems to have a better than even chance of having fallen here from the cosmos rather than having originated here. If the former, perhaps it was engineered by (as opposed to evolved from) some non-biological predecessor, but then that just defers the origin question further back, asking how those predecessors came to be. Somewhere, something had to happen just by chance, given non-deistic assumptions. Even the ID community has backed off on the life thing. The teleological argument now puts the tunings of our universe at a far lower probability than the odds of life appearing naturally.

Sounds like a definition of 'taller', which is a relation, and not how the word 'tall' is typically used. There is no standard X implied by the typical usage of the word. Ditto with life.

What benefit accrues in extending the definition of 'life' to encompass artificial intelligence?

I don't see why we could not extend intelligence, consciousness or even personhood and the subsequent legal protections, to non-living things. — Banno

If we found intelligent life out there, I doubt it would be sufficiently human to allow application of the human legal system. Exploring some cases demonstrates your prior post about the dangers of defining essence, or especially the ethical treatment owed to anything deemed sufficiently sentient life.

For instance, suppose I was to make a small modification to a human that lets one create with minimum effort a disposable child, something that just splits off with all my education and such, but looks different and lives only a few days. It kills some rival I don't like, and perhaps dies shortly after, perhaps in jail. I am innocent and minus one rival. The legal system would need to adjust.

I am amoeba man, who splits into identical halves. I get a job (and buy a house), then split. Which keeps the job or house? Does the original identity even exist anymore? There can be no legal concept of property ownership to such a being.

A computer virus goes sentient and wants to work with/for us, for pay. We give it legal status, it does tasks and earns wages that pay for consumed resources. It becomes unethical to eradicate instances of it (why, when it can effortlessly reproduce?), but one of them commits a petty crime. Do you incarcerate it? What does that word even mean to an entity living in the cloud? Terminating it seem harsh for the minor offense.

Not all life has reproduction or self-perpetuation as a goal. Humans can be anti-natalist and also suicidal. Pretty much all standard life we observe does seem organized toward these ends, but that's only because forms of life which do not tend to die out. — VagabondSpectre

A creature that is anti-natal or commits suicide for no gain is not fit and is eliminated from the gene pool. Give me an example where it is the fit thing (with no gain to the 'tribe').

Yes, I think a fully functional AI is life, and counts as consciousness, but I have a lax definition of consciousness, so its no big feat. Without a definition, it is meaningless to posit if an AI has it.
— noAxioms
An amoeba is alive but probably not "conscious". I suppose if we're to consider "consciousness" a form of or a part of life, it must be a different kind than simple forms of life such as bacteria or an unnecessary/optional feature of it. I'm inclined to say that human consciousness (and the goings on of the brain) is indeed a distinct form of life, much like a hypothetical AI. — VagabondSpectre

It is distinct from life. Something can be conscious but not be life (like an AI that doesn't perpetuate), or be life but not conscious (grass, bacteria). Mind you, I have that lax definition of consciousness, and consider all those things to be conscious, just not as much.

In the hierarchy of biological life,

Bad way to start a paragraph trying to work out what else might be life besides Earth biology.

.. in complex systems (such as connected neurons in the human brain), the physical mechanism for sentience and a higher order of life is made possible.

Life is not necessary for said complexity. Consciousness is not a factor at all. Data recording is closer to the mark, but rocks record data, and we've decided rocks are not life (or are at least far less life).

I realize that a train track lever also records data (a single bit) and is clearly not life. However, a large and complex enough system of interconnected levers which record large amounts of data in hierarchical structures could in theory produce artificial intelligence, whether by design or emergent through properties inherent in the system. Where in between a single lever and an AI is the complexity or organizational threshold for "life"? I find it an interesting question.

I think the complexity is perhaps relevant to consciousness, but not to life. It matters more how the data is used, and not so much how complex the mechanism is. Yes, Scientific American built a Turing machine from nothing but track levers thrown by passing trains.

The DNA of the Panda anticipates a bamboo rich environment. The DNA itself cannot perceive changes to the pandas habitat immediately, but through natural selection alone it can overtime, and may come to anticipate a less bamboo rich environment. — VagabondSpectre

A Panda's DNA also anticipates almost zero long term change in the habitat, which is why they're so endangered during the current mass extinction event. Dinosaurs were also sufficiently perfected that they were too slow to respond to a similar event (the asteroid being one of them).

I think I'm most comfortable with defining "life" as a kind of organism, a whole. — VagabondSpectre

Sounds biological, exempting things that clearly are not 'organisms'.

we cannot identify necessary and sufficient conditions for C, which is what an essence is understood to be.
— andrewk

not only cannot, but also need not,and indeed should not. Need not because we get by without them; and should not because doing so leads on to hold to certainty that is just not there. — Banno

I totally agree with this. Whatever we're doing attempting to define life here, a hard definition cannot come of it.

I'm a bit proponent of things like this (life, consciousness, other things) not being true or false, but rather a sliding scale. Fire is life, but not much. Religion has more life, and grass even more. A mousetrap is conscious, but nearly as far to the low end of the scale as you can get. Something can be more conscious than a human.
A dualist often interprets that word as a Boolean property: Of having/requiring that dual relationship or not. There is no scale to that unless there is a lesser mind-stuff given to lesser things, sort of like the Aiua in Orson Scott Card's "Children of the mind" (4th book in Ender series).

Imagine humans discovered a planet almost Identical to earth with a human like species yhumans. The main differences were that this planet is toxic to humans and also that there is no suffering no this planet and the yhumans there live for a thousand years in happiness. — Andrew4Handel

You just gave a pretty good description of a very non-human (non-earth-like actually) species. A non-negative-feedback-having race would not be human-like at all. Grass has a more exciting life.
In what possible way could they be like us?
You've given a description of heaven, which seems to have all the fulfillment of a person perpetually on a heroin high with hospital equipment to keep you alive against your lack of effort to that end.

Thank you, I'll remain what I am, given the choice.

Why would a fully functional AI that can think and act on it's own behalf not be considered alive? — VagabondSpectre

My examples of AI did not have self-perpetuation as a goal. The ones that did were not AI, but those I consider life if they include a mechanism to evade predation and change. A good virus has this capability since many virus detectors work with a fixed list of known viruses and look for them. A virus that changes on the fly, unpredictably, is much harder to eradicate. But is the change any sort of improvement? I don't think so.

Yes, I think a fully functional AI is life, and counts as consciousness, but I have a lax definition of consciousness, so its no big feat. Without a definition, it is meaningless to posit if an AI has it.

Of what need do we have at all for a definition? Suppose we had a perfect rigid definition. What would benefit from it? What argument (besides "is this life?") would be laid to rest with such a definition at our disposal? It just seems to be an unimportant language issue to me.
— noAxioms

It's about trying to understand what makes life life. The hunt for a sensical definition is tied to our efforts to try and comprehend how and why life does what it does. If we had a better understanding of how carbon based life organizes itself, we might have a better idea of how non-carbon based life might also organize itself. — VagabondSpectre

I doubt much would be related. If religion was considered life, I don't think understanding biology would help understand how religion achieves the natural selection that makes for fit religions. Religion is closer to life than fire (which does not undergo natural selection), but I'm reluctant to submit it as actual life.

Those all seem to be the means to achieve the persistence. If the persistence can be had without data storage, I think it would still be life. Would help if I could come up with an example.
There are plenty of life forms too primitive to anticipate their environment, and they persist more by prolific reproduction than to actually influence behavior.
— noAxioms

Not all life successfully anticipates it's environment, but prolific reproduction as a means of ensuring long term survival does anticipate the environment. It anticipates harsh conditions, and uses numbers as a strategy to overcome them. — VagabondSpectre

Does the individual do that? Does the DNA anticipate anything? It is admittedly a function of conditions, and thus a reaction to them, but anticipation goes a little too far. Ditto with religion, which used to be evolved for more stable environments, but has seen more instability lately, and thus has selected for more adaptable members, just like humans might be a train wreck example of individual fitness, but our advantage is that adaptability. Pandas are sort of the opposite: perfected for a niche at the cost of almost any adaptability. Surprised they're still around given the recent hits to their environment. Score a few points for cuteness I think.

Natural vs unnatural (inevitable vs avoidable) is a red herring loaded with baggage. How can you tell the difference between something that is natural and unnatural? If it happens, we call it natural, unless we really don't understand it, in which case we arbitrarily call it unnatural. — VagabondSpectre

There you go destroying my definition. Indeed, it might clarify the definition of life, only by use of a totally baggage-laden word like unnatural. Certainly the word is not something for which there is an definitive test, but I have an attempt: Earth biological life is unnatural since we have found nothing like it thus far anywhere else. Doubtless it is out there, and there's a better than even chance that it came elsewhere than originated on Earth, but it still had to originate somewhere and that seems to be a seriously rare event. Religions on the other hand do not have common ancestry (that I know of) and are likely to have started independently in many places. I'm pretty sure that if it were all wiped out and populations were kept isolated, new religions would spring up in each of the population groups. So that makes it natural. I'm unaware of such experiments being performed, so it is conjecture.

There might be such a point. When strands of DNA begin to fold onto themselves and create three dimensional structure, it is in the process of turning non-living matter into the beginnings of a living cell. — VagabondSpectre

It seems it is already living at that point, giving rise as to when matter transforms from a floating nutrient to actually part of the living thing. Without that distinction, I don't think we can answer this. With that distinction, we perhaps have a better clue as to what we want to define as life. What percentage of my body weight is actually living material, and how much of it is just stored liquid, food, and other material just being carried around, but not really part of me? I bet there's no clear answer to that.

Decoding the physics and chemistry of human intelligence is well behind other fields of biology, but what about artificial intelligence? Granted we don't have a true one yet, machine learning is already extraordinarily powerful. — VagabondSpectre

I would differ on this opinion. We have AI that learns, but it is not life. We have some very non-AI computer code that much more qualifies as life. You seem to ascribe more intelligence to mitochondria than to an AI that can, from looking at a snapshot of your skin, distinguish melanoma from benign conditions, better than a well trained doctor of dermatology. But the cancer-detecting AI is not making decisions for the benefit of its continued existence.

We aren't in dire need of a rigid or flawless definition, as you say (if there is one), but it's intriguing to see how close we can reasonably come. — VagabondSpectre

Of what need do we have at all for a definition? Suppose we had a perfect rigid definition. What would benefit from it? What argument (besides "is this life?") would be laid to rest with such a definition at our disposal? It just seems to be an unimportant language issue to me.

Anomalous "persistent patterns" seems like a broad and rough but fair description that applies to "life", but intuitively life is more than just a complex persistent pattern; it's a particular kind of complex pattern. It's a pattern that, for example, records large amounts of data in hierarchical structures which is used to inform behavior in a way that anticipates it's environment. Life reacts to it's environment with intelligence. — VagabondSpectre

Those all seem to be the means to achieve the persistence. If the persistence can be had without data storage, I think it would still be life. Would help if I could come up with an example.
There are plenty of life forms too primitive to anticipate their environment, and they persist more by prolific reproduction than to actually influence behavior.

Religion is an interesting metaphor for life (and vice versa) because it shows how complex behavior (self-propagation) can result from recorded data, but the self-proliferation of religion is largely an abstraction of the behavior of already living humans, not strictly behavior of the religion itself (which has no internal decision making property of it's own and is mostly intelligently developed by humans themselves). — VagabondSpectre

Human minds (and eventually written records) are the medium in which religions live, but religions are not humans, and are not objects any more than fire is an object. It does reproduce and evolve, but I decided it was too natural (inevitable) to meet my definition.

The brain has no such capacity. A human (or other creature) does, but a brain by itself can do none of this. Don't ascribe life to just one part of the functioning machine. Brains are not life forms any more than a car engine can get me to Chicago. A brain is also not consciousness. The processes of the brain might be, but the processes are not an object, and neither of them is life.
— noAxioms

A beating heart is not "life" in and of itself, although the cells which comprise it individually could be considered "alive" and a satisfactory example of "life" (even though removed from their system they quickly die). That said, the brain, along with it's accompanying nervous systems is what connects parts of the machine together. The body is the machine but the brain is the conductor. The brain produces consciousness, and consciousness itself surely qualifies as "life". — VagabondSpectre

I disagreed with this above. You can have either without the other, so they're different things. The brain is just a part, an essential one to a human, but not the only essential one, and certainly not essential to be life, since most life doesn't have one. It can be alive, or can be a dead brain, but it is not itself life.

Creating biological "life" is what DNA does — VagabondSpectre

We have no clear definition, and DNA seems a tool to perpetuate life, but I would never say it creates it. It seems that at no point is non-life transformed into life by DNA.

You might start inexplicably banging your chest ... — VagabondSpectre

True that. I'm the first to admit our behavior is more chemical than circuitry. Imagine what the ape DNA would do instead of just the female DNA. :s

Banno is correct in that we're not going to get the definition we're looking for since it is too vague. Fun trying though. You still haven't commented on my attempt. It probably has counter-examples but its hard to see exceptions to one's own rule.

O.K, let's talk about the brain then, along with it's accompanying nervous systems. The structure of the brain and it's goings on is what produces human intelligence, and we know that as the human brain acquires data it has the capacity to increase in complexity and sophistication in the decisions it makes. — VagabondSpectre

The brain has no such capacity. A human (or other creature) does, but a brain by itself can do none of this. Don't ascribe life to just one part of the functioning machine. Brains are not life forms any more than a car engine can get me to Chicago. A brain is also not consciousness. The processes of the brain might be, but the processes are not an object, and neither of them is life.

Not only does our DNA in fact make decisions for us (like when to mate for instance), but it also uses data it gathers from the environment through trial and error in order to increase it's own internal complexity and sophistication in decision making.

A human is actually DNA's way of making more, and better, DNA. — VagabondSpectre

Does DNA make the decision as to when to mate? I mean, suppose my male DNA was suddenly changed to something else at say prepubescent age 12, let's say to that of a male gorilla or a female human. Would that change the decision? Arguably it would, but most of the physiology of when that change takes place is already there and not really a function of DNA. I'm not enough of a biologist to support or deny the claim.

The DNA is of course responsible for the design of said physiology that eventually makes the actual decision to hit puberty. But the DNA doesn't seem to do the instinctive work, it just hires the contractors that do it.

I'd like to go out on a limb and try to defend the following definition of life: Self perpetuating intelligence. Any and all criticisms would be appreciated.
...
By "self-perpetuating" I don't mean "able to reproduce" or "emerged on it's own", but rather that the "intelligence" itself (the complex decision making (involves memory)) is capable of internal development (an increase in complexity). This is what differentiates a smart phone as non-life from mold as life: the mold can evolve and get smarter.

From this, here are some examples of things that qualify as life:

Human consciousness
Grass
single-cells
Mitochondria
"Artificial" intelligence — VagabondSpectre

The first one is the least qualified to be on the list. Sure, humans, but human consciousness does not seem in any way to be a life form. It is not self-perpetuating, and seems to be debatably an effect as much as an agent for decision making. A human is intelligent, not the consciousness itself, unless the consciousness is defined as a synonym for the immaterial entity as dualist commonly use the term, in which case we're not talking about physical life at all, and we have no data about reproducability or capability of increase in complexity

You label the function of DNA as "intelligent.decision making" which stretches the definition of the words. Plenty of complexity there, but does it qualify as decision making?

Kindly comment on my definition of "an unnatural persistent pattern". I had wondered if religion qualified as a life form since it meets a lot of qualifications, especially reproduction. But I decided it was like the fire: It is a process that naturally (inevitably) happens with sufficient fuel laying around and is thus natural, not unnatural. Concerning fire:

Almost, but not quite: A fire is not made out of organic matter, because it is not matter at all but energy. Granted, organic matter is one of the causes of fire, but not the thing itself, as an effect is a different thing than its cause. — Samuel Lacrampe

Fire is a process, just like life, and I have already stated that life being organic is a circular definition and excludes anything that isn't exactly like us. We want a definition of life, not of Earth life. Fire is not life because it is natural, even though I'm not sure there would be fire at all on Earth if not for the life on which it feeds. Imagine a lifeless Earth. What would burn? Methane is inorganic, but without free oxygen, it's not going to burn.

I suggest to limit the discussion to material life for now. — Samuel Lacrampe

Agree to that, but that means consciousness is not life, at least not by material definitions. There can be life without it, and consciousness without life. They're separate things.

So the new list for material life is as follows:
- proper functioning of the object's parts
- needs a form of energy — Samuel Lacrampe

The first is part of the definition of 'alive', not of life. It need not be an object. Life is a process, and processes require energy, living or not. So I would reject both these items. A clock that has stopped due to lack of winding meets this definition. I like the definition above better (self-perpetuating intelligence).

AI by itself is not necessarily self-perpetuating. They have AI now, but certainly it has not achieved self-reliance. What they often call AI, such as in a self-driving car, is not true AI. It is a straight automaton executing very specific code. Done correctly, the car should learn from mistakes and share that knowledge with the other cars. I don't think it currently works that way.

A long time ago Wayfarer (who seems to support something akin to vitalism) asked me this question. I provided this definition as my best attempt, which was not warmly received:

Life is an unnatural persistent pattern.

It has have had natural origins of course, but it is not really life until it (via evolution in our case, but not necessarily) becomes something that has no reasonable probability of just accidentally occurring.

Anyway, the definition distinguishes life from fire, and many definitions fail that. I think the computer virus qualifies as much as a biological virus.

I think the distinction between the worm theorist and stage theorist is suspect. The crashing of the Titanic happened over a finite duration. If we stick to the distinction strictly, the so called stage theroist who isolates a crashing Titanic is effectively posing a worm when we examine just how many finite instances are involved with the accident-- the hitting the iceberg, beginning to sink, and so on, to give a simple example. — TheWillowOfDarkness

Suspect of what? The identity distinction seems to hold no metaphysical importance at all except to those views that require to tie some non-physical identity to something physical for the purposes of judgement in the non-physical realm.
So one uses whichever language for is appropriate for the concept being conveyed at the time. I can speak of the reasonably momentary event when the Titanic disappeared entirely below the waterline, or the draw out worm event of the tragedy, or the duration of the Titanic as a whole which had no obvious beginning or end. "See this grease-spot region of somewhat higher mineral density on this (year 3000) map of the ocean floor? That's the Titanic." A true statement I guess, but then when does it stop being the Titanic? I actually chose the iceberg itself as my example because it was one we all know, and it is something that clearly has no stage component in 2017.

If we are to have an account which fits, the worm and stage must be complementary rather than opposed. The Titanic has to be both a stage (not crashed, crashing, after the crash) and a worm (a particular object with a past and future). Otherwise, we cannot say it is the Titanic which was steaming along unhindered, only to change to make contact with an iceberg, and then alter again into a sinking wreck. — TWoD

You use whichever form is convenient. I deny numeric identity of something like the Titanic between the various stages of the Titanic. For one thing, what happened to that identity when the two halves separated? Yet I use the worm form as a language concept that conveys real meaning.

In other words: a worm must be a function of many stages, an expression which not any particular stage or moment, given across many stages which are never each other. (e.g. Titanic steaming along, crashing Titanic, wrecked Titanic). — TWoD

Is the crashing Titanic the same one as the steaming Titanic? Certainly two stages chosen from those to states are not the same stage, but are they stages of the same thing? Is a worm an identity? I have a very strange answer to those questions, which is no, the various stages are not of the same numeric identity of Titanic, but they are stages of the same identity of worm. In my view, there is a 1-1 correspondence between a worm and a stage, it being the stage at which the worm ends, and the stage only being defined from a reference point in that stage's future. All the stages making up the worm are part of it, but do not share numeric identity with the worm, since they don't share that identity with each other.

I probably didn't state that very clearly. I have spotty time to respond right now.

So you want to find essential properties that distinguish lifeforms from non-lifeforms right? How about these:
- can reproduce,
- can grow,
- is made of organic matter (DNA, carbons, proteins ...)
- needs a form of energy — Samuel Lacrampe

The list seems to define 'life' (and thus better addresses the OP) than a lot of the prior discussion about distinguishing 'alive' from 'dead'. The latter is already a life form, but one that has ceased to function.

As to the list, I don't want to be a pain but every one of them is debatable, and it might not be a complete list of necessary traits. A monotheistic god is not alive by the list above since there is no reproduction. If we encounter some huge great immortal intelligence in the galaxy, are we not to recognize it as life because it has no need to reproduce, and no critical parts the loss of which it cannot recover?
So the list above seems to be a list of symptoms, not hard requirements.

Maybe a we will create a truly self-sufficient computer life form that manufactures new members at full size, so no growth, and no organic matter. Many would not regard that as life, so I would like to ask why the list seems to have a geocentric item like that on it? Why must life be sufficiently like us, who just happen to be carbon based which is chemistry well suited to the available components and temperature of Earth.
'Organic' doesn't belong on the list because it is circular. It means stuff created (typically) by life.

What about a virtual life form in the cloud? Are computer viruses life? They meet all the criteria above except organic (being like us).

Needs a form of energy doesn't belong on the list. So does the car.

I think the question is ill formed. By definition, there cannot be the iceberg which takes out the Titanic in 2017-- neither the Titanic nor the object it hits are present in that moment. — TheWillowOfDarkness

Didn't think I claimed that. The statement references 2017, and I chose the iceberg as my example of something that does not exist in that year.

In the reasoning you are giving here, you are only accounting for identity in terms of the past. We realise the particular iceberg exists in 1912. But it doesn't account for the change of the future. Instead of realising any iceberg after the Titanic is a different state, a new moment, which the Titanic does not hit, you still thinking of it as the same state and moment of the crashing Titanic.

Not following this. I'm thinking of subsequent states (different icebergs??) as being the same event or state as the Titanic sinking one? I'm probably parsing you wrong here.

It's not. The iceberg in question ceased to be at the end of the Titanic's crash. (and not because it broke apart or anything like that, but rather because it is a different state of time).

OK, that makes somewhat more sense, but seems to be more the identity thing that distinguishes the stage theorist from the worm theorist. We were discussing "as a worm being" which retains identity of a thing over a finite duration. Under the worm definition of identity, the iceberg continues existence after the Titanic hits it but eventually breaks up/melts.

For other reasons than any stated in this thread, I don't consider my present version to share numeric identity with my 2010 version, and thus, from a numeric identity perspective, am something like that stage theorist, but I also don't apply the label of "I" or "me" to any given state, and I think the stage theorist might do that. I was not particularly aware of the term before this thread.

Under the worm theory, I am the entity that identifies with the entire worm. There is no other entity I can be. — Mr Bee

Is that the "I" that has no experience of 2010? How does your 2017 component come by memory of that year if it is not part of your experience?

This post was confusing because of the switch between A and B series references.
It illustrates that it needs to be stated up front before declaring something to exist or not.

'So,' I'd say, 'it is both true that dodos exist and that they don't exist (any longer)'?

'It depends' you'd say 'whether you're speaking as someone in 2017 or as someone speaking from a block-perspective.' — csalisbury

It went sort of bad in those two lines. The question above mixed A and B references in the same sentence, rendering its meaning ambiguous. The reply is related to what I posted in my prior post, but not worded carefully.
A-series: Dodos went extinct. (implication that they don't exist now)
B-series without reference: Dodos exist. Jabberwockeys do not.
B with reference: Dodos are extinct after 17th century. Dodos don't exist in 200m BC.

The middle one lacks any reference to a specific time, and thus can only mean exists at some point in time.

'But both apply to you!' I'd say. 'Are you saying that you can hold two contradictory statements to be true, by reference to two different perspectives? Two perspectives you're incapable of occupying separately (since, try as you will, you'll still be talking in 2017.)? That doesn't make sense.'

B-series statements are never given from any perspective that one can occupy. The location of the utterance or the receiving of the statement is irrelevant to the content of the statement.

We seem to be discussing only language usage, which seems to be completely irrelevant to the validity of eternalism.

(Note that the conversation would have gone smooth as butter if we weren't talking about whether dodos exist, but whether 2+2=4 or the pythagorean theorem)

Maybe not. Does 2+2 objectively equal 4 or is that just property of this universe? OK, now we're waaay off topic.

What do you mean by 'presence'? — csalisbury

Well, I mean exists, but I was trying to express a definition, and it seemed circular to use the word in its own definition.
I exist. My third grandmother does not. The iceberg that takes out the Titanic exists.

All good and fine, but given that definition, how does one say that something is in the block, but has a finite temporal duration, and the reference-time is not part of that duration? If the iceberg exists period, how does it not exist in 2017? So it seems that the word 'exists' is context dependent. If no temporal reference is given, it just exists or not. But if a reference is given, the word is taken to mean the duration of the thing does not include the referenced time.
That's two different valid usages of the word depending on context. Seems reasonable, no? Else we need a separate word for the two usages. Notice that at not point do I need to fall back to a past/future-tensed usage. The iceberg exists in 1912, not existed, which would be an A-series statement.

Right, and, furthermore any felicitous use of 'exist' will involve it being tensed in accordance to a reference point (a 'now'). From the reference point of 2017, 2010's noAxiom existed. And from the reference point of 2017, 2017's noAxiom exists[/i.] — csalisbury

Right you are, illustrating the danger of using A-forms. I used 'exist' without a definition of it. If it means any presence in the block, then there is no valid use of the tense 'existed' or 'will exist'. I suppose the growing block view invalidates only the former of those two tenses.

What is the reference point you were making use of when you said "As a worm being, I exist in 2010 as much as I exist in 2017'? The answer is no reference point at all. In other words, you're using 'exist' to mean something radically different than it means in ordinary usage.

I meant what I described above, but yes, I used the word differently in a later post. I was using B-series terminology in saying I exist in 2010. There is no 'existed' tense at all in B-series.

Existence is always tensed, so when, for instance, noAxioms says "As a worm being, I exist in 2010 as much as I exist in 2017,' it's clear that something is amiss. noAxioms does not exist in 2010 though it's true (I imagine) that he existed in 2010. — csalisbury

The B-view is almost necessary when discussing from a block viewpoint. To say 'existed' is to reference a moment in time that the view denies. The A-view is not wrong, but leads to misleading usage of language such as:

But as a worm being, does he exist in 2010? No more than he existed in 2010, or will exist in 2010. But if, qua worm being, he simultaneously existed, exists, and will exist at all times (during the life of the worm being), then we're using 'exist' in an entirely novel and extremely fuzzy way. — csalisbury

But from the reference point of 2005, the 2010 version will exist, without conflict. Confusing since the language used carries an implication of a point of reference without the need to have it explicitly stated. So the verb tenses used by the A-view are inappropriate, but not incorrect.

Mr Bee is using A-references (such as ambiguous "I") in discussion of absolute things, and getting the expected conflicts. Eternalism is an objective view of time, and objective terms should be used at every step.

I think your objection falls into the same mistake of mixing up my claim that I am only experiencing a certain set of experiences (my P3.) as a claim that I am having a certain set of experiences at a particular time. I am simply not making the latter sort of claim. — Mr Bee

You need to clarify your claim. What is "I" in that statement above? The 2017 component that has no direct experience of 2010, or the entire-worm-self "I"?

Correction, what you have described and driven to inconsistency is something else unrelated to my argument. That is what I mean when I say you are making strawmen. — Mr Bee

Point out my inconsistency please.

So much as the whole spacetime worm has the 2010 person as a temporal part, then we should expect this spatio-temporally extended being to have the 2010 joys. — Mr Bee

The interpretation says this being does have the 2010 joys, but it does not say that the 2017 subcomponent has direct access to 2010 state (or 2020 for that matter). There seems to be an assumption that one must have simultaneous access to the experience of all of your being, which is not a property of a temporally extended definition of a being, since the being is not simultaneous (by definition).

And you should perhaps get a better understanding of what I am saying first before making such claims. — Mr Bee

Fine. The model as you explain it is clearly conflicting, as you demonstrate in your OP. The only mistake is labeling the model 'eternalism'. What you have described and driven to inconsistency is something else.

Not really. Presentism also denies that any time other than the present exists. There are views that have a priveliged present but do not deny the entire structure of the block universe (growing-block views for example). — Mr Bee

OK, I grant that. Growing block seems to adopt the worst features of both views. Not sure what problem is solved by the block history, but the lack of block-future seems to be an attempt to get around one's discomfort with the free will implications.