What Is the Definition of Life?

[GaianDave51]

We all have a working definition of the word "Life". We all have an intuitive grasp of what makes something a living thing. Is this enough to go on with?

As a bio-ethicist, I need to be able to define precisely the central subject of my philosophizing. I'll make a stab at it here, but I know I'll need lot's of help from you folks. So here goes.....

A Living thing -

- Is a bounded, thermodynamically open system; - Uses energy to process matter; - Maintains homeostasis, far from thermodynamic equilibrium, over time; - Is, in aggregate, subject to the processes of Evolution.

How's that for a start?

[Atreyu]

Not too bad, but only if by "life" you mean "life on Earth" or "life as we know it", or something else along those lines.

But that is not what you said. You said "life", period. And here is how I would define that (although I know that is not really your question): Any entity which has awareness, i.e. has a psyche of any kind or form.

[Artimas]

Not too bad, but only if by "life" you mean "life on Earth" or "life as we know it", or something else along those lines.

But that is not what you said. You said "life", period. And here is how I would define that (although I know that is not really your question): Any entity which has awareness, i.e. has a psyche of any kind or form.

What about animals which aren't self aware, plants? I was going to say the same thing about the "Life" topic though, wasn't quite sure on how to answer the question. I was thinking he was asking what life was about, or the philosophy of life. I was about to say, to learn, love, teach, and grow. Rinse and Repeat my friends.

Earths periodic table, and everything Earthly we know, Life as we know it.. is but a spec in the universe, there are a plethora of other realities, a vast plethora. I don't think humanity can really define life, without first visiting the rest of the universe. The possibilities are endless, we could encounter anything from zombies which are living but dead, all the way to moving, breathing oozes. You never know.

[Atreyu]

What about animals which aren't self aware, plants?

My opinion is that all life as defined by science has some kind of awareness, even plants, microbes and viruses.

The bigger question, IMO, is whether or not there is awareness which is not defined as "life" by science.

[Artimas]

What about animals which aren't self aware, plants?

My opinion is that all life as defined by science has some kind of awareness, even plants, microbes and viruses.

The bigger question, IMO, is whether or not there is awareness which is not defined as "life" by science.

I completely agree. That is a good question.

[GaianDave51]

Thank you, Artimas and Atreyu,

Conscious self-awareness is an emergent property of living systems - living things and the ecosystems in which they function - , but emergence is a time-bound process. In the case of humans, conscious self-awareness emerged, from the first living cells, after about 4.4 billion years. Therefore, I don't think self-awareness (conscious or not) is a defining characteristic of Life.

The four aspects of living things that I offered in the original post certainly do not preclude the development of non-carbon-based life, or life elsewhere in the Universe. In fact, I believe that both are very likely to have happened.

I noticed that neither of you raised the aspect of Self-Reproduction as a part of the definition. This is correct. Niches, ecosystems, biomes, and the Biosphere itself, are all living systems, but they do not reproduce. They evolve over time.

There is one aspect that I left out of the definition, because I'm very unsure about it. I hope you folks out there can help me with it. I'll put it in the form of a question: "Is the creation and processing of information a function only of living things?"

[Artimas]

Thank you, Artimas and Atreyu,

Conscious self-awareness is an emergent property of living systems - living things and the ecosystems in which they function - , but emergence is a time-bound process. In the case of humans, conscious self-awareness emerged, from the first living cells, after about 4.4 billion years. Therefore, I don't think self-awareness (conscious or not) is a defining characteristic of Life.

The four aspects of living things that I offered in the original post certainly do not preclude the development of non-carbon-based life, or life elsewhere in the Universe. In fact, I believe that both are very likely to have happened.

I noticed that neither of you raised the aspect of Self-Reproduction as a part of the definition. This is correct. Niches, ecosystems, biomes, and the Biosphere itself, are all living systems, but they do not reproduce. They evolve over time.

There is one aspect that I left out of the definition, because I'm very unsure about it. I hope you folks out there can help me with it. I'll put it in the form of a question: "Is the creation and processing of information a function only of living things?"

Machines can process and create new information, do we define them as living?

It is very hard to define what is life and what isn't, when we do not know what is completely out there yet. We don't even know what is in our oceans and on our own "home planet", let alone what is out in the universe.

The universe is MUCH bigger than our one planet, so for us to try and define life when we haven't even looked through our own planet yet, will be very difficult. Not sure if it can be answered without proper and adequate information, in due time though friends.

We don't even have one planet under our belt yet. I think two planets at the very least would at least be required to make an adequate decision of what life is or could be.

[Bohm2]

.There is one aspect that I left out of the definition, because I'm very unsure about it. I hope you folks out there can help me with it. I'll put it in the form of a question: "Is the creation and processing of information a function only of living things?"

There's a problem with the definition of 'information' also, as another poster mentioned when discussing computers. But as you mention some authors like Davies and his group do argue this aspect:

Although it has been notoriously difficult to pin down precisely what it is that makes life so distinctive and remarkable, there is general agreement that its informational aspect is one key property, perhaps the key property. The unique informational narrative of living systems suggests that life may be characterized by context-dependent causal influences, and in particular, that top-down (or downward) causation-where higher-levels influence and constrain the dynamics of lower-levels in organizational hierarchies-may be a major contributor to the hierarchal structure of living systems. Here we propose that the origin of life may correspond to a physical transition associated with a fundamental shift in causal structure.The origin of life may therefore be characterized by a transition from bottom-up to top-down causation, mediated by a reversal in the dominant direction of the flow of information from lower to higher levels of organization (bottom-up), to that from higher to lower levels of organization (top-down).

The Algorithmic Origins of Life
http://arxiv.org/pdf/1207.4803v1.pdf

[Teralek]

A Living thing -

- Is a bounded, thermodynamically open system; - Uses energy to process matter; - Maintains homeostasis, far from thermodynamic equilibrium, over time; - Is, in aggregate, subject to the processes of Evolution.

Coincidently I thought about this recently. I have no problem with your definition to start with but it can be improved.

Arguably Stars maintain homoeostasis and thermodynamic equilibrium for a long time, they too are subject to evolution in a different way. Not they they adapt but they form 2nd and 3rd generation stars. Making them different than their progenitor stars.

Some people say that humans created an enclosed ecosystem and thus removed themselves from the survival struggle and are not subject to the processes of evolution like all other species.

Thus I think instead of evolution you should say "subject to the processes of reproduction or replication".

Finally I think you should add that life can also be defined by self aware capacity and perhaps free will choice. In effect opening the possibility of artificial created life. I know that all hell can break loose by going this way but that's how I would define it...

[Artimas]

A Living thing -

- Is a bounded, thermodynamically open system; - Uses energy to process matter; - Maintains homeostasis, far from thermodynamic equilibrium, over time; - Is, in aggregate, subject to the processes of Evolution.

Coincidently I thought about this recently. I have no problem with your definition to start with but it can be improved.

Arguably Stars maintain homoeostasis and thermodynamic equilibrium for a long time, they too are subject to evolution in a different way. Not they they adapt but they form 2nd and 3rd generation stars. Making them different than their progenitor stars.

Some people say that humans created an enclosed ecosystem and thus removed themselves from the survival struggle and are not subject to the processes of evolution like all other species.



Thus I think instead of evolution you should say "subject to the processes of reproduction or replication".

Finally I think you should add that life can also be defined by self aware capacity and perhaps free will choice. In effect opening the possibility of artificial created life. I know that all hell can break loose by going this way but that's how I would define it...

I agree as well.

[Atreyu]

I don't like the definition because I think it misses the "key" attributes that we ordinarily associate with life. When I consider "a bounded, thermodynamically open system; - Uses energy to process matter; - Maintains homeostasis, far from thermodynamic equilibrium, over time; - Is, in aggregate, subject to the processes of Evolution", I don't necessarily envision a living organism. I can imagine something not alive having all of those attributes other than perhaps the last --- "subject to the processes of evolution". The definition doesn't seem to nail down the attributes that we ordinarily associate with "life" in our day to day existence, nor even the attributes generally recognized by science.

For example, when we consider whether or not the virus is "alive" or not, are we really thinking about things like "homeostasis", "thermodynamic equilibrium", or "the processes of evolution" ? I myself am certainly not. I'm thinking more along the lines of "does the virus have will?", "does the virus have awareness", or "does the virus have any desires or feelings" ? I am not measuring the virus against some preset list of "defining attributes" that I or someone else decided "defined life".

It's difficult if not impossible to "define life" because we really don't differentiate between "life" and "non-life" on the basis of words, definitions, formulas, or other "technical" or so called "scientific" parameters. In reality we make this distinction based on very subtle feelings and intuitions we have about the objects that surround us. Some of the objects appear "alive" while others do not. Some of the objects appear to have a certain "animation", "will", or awareness present which we do not detect in other objects. We don't know for sure if in fact there is any inherent difference, any different matter or energy present, any awareness or psychic activity, but that is not important. What is important is that it is sensed and assumed for some reason in some objects but not in others. So defining the key attributes comes down to knowing our own psychology and psychology in general just as much as it does knowing various attributes that scientists have theorized as only pertaining to "life".

[Lacewing]

I remember many years ago, suddenly and joyfully proclaiming: "The whole universe is ALIVE!!". Now, granted, I was somewhat "altered" at the time -- and my revelation was immediately rejected by the brainy guy I was with. But it was a personal revelatory moment I've never forgotten, and it still feels true to me in ways that are impossible to debate. I think it's because: 1) I'm thinking that EVERYTHING is made up of energy, and there's some sort of movement on a sub-something-or-other level, and 2) I think everything is connected and communicating!

So if energy is moving and communicating, is it "alive"?

Mainly, being "alive" seems to be a human concept tied to the impermanence of material form. Much like our idea of "death". Yet we say that suns die, don't we... when most people would not say that suns were ever alive. If something ceases to exist to the degree that we are able to discern it... if its energy disappears from our view... we say it is dead. Our definition of life seems to be much more specific, although that too, is based on what we are able to discern and identify with. There's the idea that things don't die, they just change form. So I will suggest it again... could it be that "The whole universe is ALIVE!"

[Felix]

"The whole universe is ALIVE!"

Waiter? Over here.... I'd like whatever he's drinking!

[GaianDave51]

Atreyu, thank you very much,

You raise a completely different, and equally valid, IMHO, approach to a definition of Life as I attempted. You capture, in essence, the feelings we humans sometimes get when confronted with the forces and phenomena of Nature - "That storm is so violent and evil it must be alive!" - "The atmosphere of this crowd is alive tonight!" The psychological perspective on the definition of Life is one I am ill-equipped to address; Atreyu, I hope you can elaborate more.

Lacewing,

I'm intrigued with your notion of the Universe itself as being alive. The only part of my attempt at a definition that may be problematic w/r/t your proposition is the still philosophically open question of whether, thermodynamically speaking, the Universe is open or closed. BTW, the physicist and cosmologist Lee Smolin (of whom I am a disciple) might very well agree with you.

Felix,

My nephew Jason can fix you up - jayreidwrites.com Salud!

[The Beast]

The Universe might have been an open system while it was hot enough to create proton collisions. Densities cooled off and severed the umbilical cord. Universal laws translate into sentient beings. What is it that moves an arm or a rock… are not them part of us? So… is not the Universe part of me? am I a sentient being?