What is the anthropic principle and how does it relate to defining life?

[DaveC426913]

So what is the difference between a living person and the corpse at the smallest possible time interval after death?

That's circular; it depends on where you define "death" to occur.

No, let me make that more useful. The moment of death is derived. First, we define under what conditions an organism is alive, then we determine when those conditions cease, and that defines death.

Also, I'm not sure that 'dead' is the same as 'non-living'. A fresh corpse has all the potential still in it to keep life going, it's just the parts aren't working together to sustain it. That's different from a rock, which has no processes.

 

[DaveC426913]

Why not? They are at least as alive as a slime-mold (no offense to any slime-mold readers)

With this defn there is an interesting gradation between self catalyzing chemical reactions and life - which is probably where 'life' first started.

I just don't think programs can so glibly be included.

 

[Studiot]

That's circular; it depends on where you define "death" to occur.

No, let me make that more useful. The moment of death is derived. First, we define under what conditions an organism is alive, then we determine when those conditions cease, and that defines death.

Also, I'm not sure that 'dead' is the same as 'non-living'. A fresh corpse has all the potential still in it to keep life going, it's just the parts aren't working together to sustain it. That's different from a rock, which has no processes.

Which again reinforces my point the the boundary is broad and ill defined.

I deliberately used an indeterminate time interval to avoid a circular argument, my argument is not at all circular.

I think it is easier to consider the transition live to dead than dead to live. Of course if you want also to define more than two states ie alive, dead and non living, you can.
Equally you have a problem with 'alive'. In a complex entity death of all its components does not occur simulataneously. The organism may die but many cells can and do go on living for some time after.

We even acknowledge in the English language that life and death are wide ranging concepts, when we attribute them to inanimate objects and even non material ones.

The life-cycle of a product. The death of communism. and so on.

 

[DaveC426913]

I deliberately used an indeterminate time interval to avoid a circular argument, my argument is not at all circular.

Well, I wasn't suggesting you were committing an error of circularity, merely that it is the problem we're running into. That's why I chose to define an organism's death in a way that eliminates the problem by making it a derived property.

 

[BANG!]

The current definition of life (at least the one given to me by a biologist prof. years ago)
is one based on the following critereion:

1) Ability to Reproduce
2) Has a metabolism
3) Grows
4) Dies
5) Respiration

However, the two problems with this are that fire meets all of the critereion, whereas a virus does not (no metabolism). Apperently, they are technically considered "harmful particles". You can read into this as much as you want, but I think I will go find out what's for dinner instead.

 

[BANG!]

OK, the magical word just popped up.
I think what I am searcing for is what kind of "force" which is likely to make abiogenesis happen. Clearly, there is *something* which is causing elementary particles to seek together into atoms, atoms into molecules, simple molecules into organic compounds, and so forth. I would like it to be something simple and elegant, like an equation for a "tendency" towards complex systems that show negative entropy.

You can always jump on the whole "Complexity Theory" bandwagon with Murray Gelman, the creator of Mathematica (I forget his name), et. al. There is a book by M. Mitchel Waldrop on the subject, actually there are a host of books now, but this was one of the first and provides a historical overview. Or you can check out the Sante Fe Institute which studies these things. It's a real place with real scientists and not just a haven of soft-science no-nothings. Though I should mention that they initially required funding via this arguement:
Them, "were on to something, something big"
Government, "really, what?"
Them, "we don't know, but golly look at our credintials."
Government, "sure thing, how does $X million sound?"

 

[DaveC426913]

...I think I will go find out what's for dinner instead.

Well, I hope you can tell the diff between life and non-life, or your dinner may be hard to digest...

And speaking of which: how many common foods can you name that were not once alive? (I'll disqualify seasonings such as salt.)

 

[BANG!]

And speaking of which: how many common foods can you name that were not once alive? (I'll disqualify seasonings such as salt.)

This stumped me until I thought to look on the back of a doritos bag:

Maltodextrin
Monosodium Glutamate
Disodium Phosphate
Sodium Caseinate
Disodium Inosinate
Disodium Guanylate
Lactic Acid
Artificial Color
Natural and Artificial Flavor

You could argue that these are not COMMON foods, but seriously, Doritos and its brethern are about the closest thing to Amercan cuisine that I can think of.

 

[DaveC426913]

This stumped me until I thought to look on the back of a doritos bag:

Maltodextrin
Monosodium Glutamate
Disodium Phosphate
Sodium Caseinate
Disodium Inosinate
Disodium Guanylate
Lactic Acid
Artificial Color
Natural and Artificial Flavor

You could argue that these are not COMMON foods, but seriously, Doritos and its brethern are about the closest thing to Amercan cuisine that I can think of.

Well, those are ingredients. You don't eat those as food.

The one I was thinking of is honey. But then again, I guess pollen is technically seeds.

 

[Dembadon]

Common for what age?

At one point, Play-Doh and Elmer's Glue would've been on my list!

 

[DaveC426913]

Common for what age?

At one point, Play-Doh and Elmer's Glue would've been on my list!

True but Elmer's glue was once horses, and I believe Play-Doh is actually alive.

 

[Galap]

Your nature commands you to conjure junk science?

There's lots of books out there on 'The Power of Attraction' and other woo-wooism.

I'm not saying "don't search for something worthy"; I'm saying "this is a road to folly".


There's nothing mystical about emergence. FaceBook is an example of emergent behaviour. Social networking structures have properties that are not detectable in the individual components. The whole is greater than the sum of its parts.

Emergence isn't mystical, but it is easy to think it is, because so little is understood about it.

For example, intricate knowledge of subatomic particles will teach you a great deal about atoms and how they work, but it won't teach you a whole lot about chemistry. What do we do about that? Well, we figure out chemistry on its own and write the rules for that. We don't really think about WHY the emergent properties are there. We know very little about that. The only area where this gets attention is where its magnitude is the greatest, where all the errors/lack of understanding add up, is the difficulty in uniting QM and GR. Emergence essentially explains why they are so difficult to unite.

 

[Max Faust]

Emergence isn't mystical, but it is easy to think it is, because so little is understood about it.

The reason why I call it "mystical" may be somewhat unjustified, but I seem to run into this concept as a supposed "explanation" every now and then, but upon asking the (to me) perfectly legitimate question 'well what is it then?' I usually only get vague and foggy answers, and/or the end-all-discussion-suggestion that I should "look it up".

However, *emergence* may just be what I'm looking for. Is there any way of 'catching' the phenomenon within a simple equation?

Edit: "Equation" is the wrong word. I'm quite good at *imagining* things but I'm a mathematical illiterate.

 

[Max Faust]

You can always jump on the whole "Complexity Theory" bandwagon with Murray Gelman, the creator of Mathematica (I forget his name), et. al.

Do you mean "Bertie"? (Bertrand Russell).

Anyway, thanks for the hint. I shall have a look into said bandwagon.

 

[Phrak]

Well, do computer simulations count? They fit that definition.

Yes, I would include computer simulations. I think most people wouldn't..

 

[Andy Resnick]

This discussion reminds me of another one, where we try to define what is the color 'blue'. Someone says "blue is 450 nm wavelength light", another says it ranges about some spectral band (somewhere between purple and green, with sidebar discussion on where the boundary should be), and yet another (the color blind computer programmer) claims some things are blue but most people disagree.

Clearly the line between alive and dead is not so clear: when we die, most of our cells are still alive (we even harvest them for research). Some of these cells can live for days or longer (chondrocytes, for example). It's also apparent there is *some* difference between living systems and non-living systems: we can convert living to non-living, but not the other way around.

I maintain that Physics has an opportunity to make a real contribution by bringing quantitation to the question of living/nonliving. There's a tradition of physicists making progress on this question, but unfortunately a lack of real results.

 

[Max Faust]

The one I was thinking of is honey. But then again, I guess pollen is technically seeds.

Honey isn't made from pollen! (Pollen is more akin to "sperm", BTW.) Flower-nectar!

My mind went to "dairy products" upon this question - since milk is a body fluid, but not thought of as "alive" as such, in and of itself.

 

[DaveC426913]

Honey isn't made from pollen! (Pollen is more akin to "sperm", BTW.)

DNA packages either way.

Flower-nectar!

Fair enough. So it was once a fluid of a living thing.

My mind went to "dairy products" upon this question - since milk is a body fluid, but not thought of as "alive" as such, in and of itself.

Good point. Honey is no less a product of a living thing than milk is.

 

[Archosaur]

I like to think of life a little more generally, and through more of a physics lens.
Someone has already said something similar, but I like to think of life as local systems of negative entropy, specifically those that become more ordered through cumulatively selective processes. So, I, unlike many, would consider viruses to be alive.

"No, viruses are just a bunch of chemicals," said my bio prof.

"How many chemicals do you have to be, before you're considered alive?" I asked.

It got a laugh out of the class, but no good answer.

 

[mgb_phys]

"No, viruses are just a bunch of chemicals," said my bio prof.

Are viruses alive is a good question - it just doesn't have a good answer.
It was always a favorite university interview question - it gets people thinking rather than just have them parrot out the answer.

It's also worth asking a class for statistical purposes, maths/physics/chemists all say yes (life is just a level of complexity), biologists/medics tend to say no (they have learned the defn of life)

 

[Archosaur]

biologists/medics tend to say no (they have learned the defn of life)

Yea, and that definition includes the qualifier that life has to be composed of cells. How arbitrary is that?! Why not a mass requirement, or favorite color? Of course I'll concede that it is incredibly unlikely that intelligent life would develop with non-cellular structure, but if such "beings" come to our planet looking for a cup of sugar, what then?

"Nope. You guys aren't even alive."

 

[Andy Resnick]

It's not completely arbitrary- a cell is the smallest self-contained unit of living matter. Viruses must hijack a cell to make copies- they cannot reproduce on their own (nor do they 'eat').

I suppose it's possible to imagine other alternatives, but on Earth anyways, cells are the basic building block.

 

[Studiot]

Including cells in the definition adds the complication.

For any aggregate of cells, some living some dead, is the aggregate alive?

Is there any difference between the 'life' of an aggregate and the 'life' of a single cell?

 

[Phrak]

It's not completely arbitrary- a cell is the smallest self-contained unit of living matter. Viruses must hijack a cell to make copies- they cannot reproduce on their own (nor do they 'eat').

I suppose it's possible to imagine other alternatives, but on Earth anyways, cells are the basic building block.

This is an excellent example. The counter-argument is that many cellular organisms rely upon acquisition of preexistant material to live as well.

Somewhere, inbetween, notice that both the virus and the host cell in unison generate more viral particles. In this perspective there is not one living organisms hijacking another, but a synthesis of genetic material in cooperation, as required, to produce more viral particles.

In the process, most of the genetic material of the host cell is unused. This is not a deficit to reproducing more viral particles, as there are plenty of other mates available to supply the missing chromosomes. The same enviromental dependency occurs in sexual reproduction on a more limited number of chromosomes.

A living system need not be physically localized.

 

[Pythagorean]

Viruses are a very Interesting aspect of this discussion. I've always considered them a sort of wrench in the cogwheel, more so than a lifeform.

I would also generalize Q Goest's definition to genes, not the specific DNA type molecules.

 

[Andy Resnick]

Including cells in the definition adds the complication.

For any aggregate of cells, some living some dead, is the aggregate alive?

Is there any difference between the 'life' of an aggregate and the 'life' of a single cell?

That's essentially the 'Delphic boat' parable. Given that living systems constantly replace parts, what does it all mean for the ensemble?

http://en.wikipedia.org/wiki/Delphic_boat

 

[Andy Resnick]

Viruses are a very Interesting aspect of this discussion. I've always considered them a sort of wrench in the cogwheel, more so than a lifeform.

I would also generalize Q Goest's definition to genes, not the specific DNA type molecules.

There's also prions. Prions are infectious proteins. They convert normal proteins into misfolded proteins that resemble themselves.

Again, physics can make some real contributions here- we excel at finding underlying patterns and 'rules'.

 

[DaveC426913]

It would appear that no definition of life can concentrate on the parts; it must concentrate on the processes. So it is not about the cells themselves but about their metabolizing.

 

[Studiot]

So it is not about the cells themselves but about their metabolizing.

So is dormant life then dead?

 

[Andy Resnick]

It would appear that no definition of life can concentrate on the parts; it must concentrate on the processes. So it is not about the cells themselves but about their metabolizing.

I think that's the right approach- 'life' could be defined by how parts functionally relate to (and perhaps modify) each other, not the parts themselves.