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

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The discussion centers around the challenge of defining "life" from a physics perspective, highlighting the inadequacy of existing definitions. Participants explore various concepts, including Erwin Schrödinger's idea of life as a system exhibiting negative entropy and the complexities of biological processes. The conversation raises questions about whether non-traditional entities like crystals or flames could be considered alive, emphasizing the difficulty in establishing clear boundaries between life and non-life. Many contributors suggest that current scientific understanding is insufficient for a concise definition, advocating for a broader view that encompasses all forms of existence. Ultimately, the debate underscores the intricate nature of life and the limitations of definitions in capturing its essence.
  • #101
Sea Cow said:
Biological processes are not reducible to physics.

I cannot put into words how strongly I disagree with this. The barrier you perceive between biology and physics, or between any two fields of study, are social constructs, not properties of the universe. Don't departmentalize that which doesn't need to be. Yes, the physics behind a cell is enormously more complicated than a system of pulleys, but can you really argue that that they follow separate rules?

Just as we are debating the level of complexity that warrants the name "life", can you tell me what the simplest form is that falls exclusively under the jurisdiction of biology?
 
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  • #102
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  • #103
DaveC426913 said:
the third option is that life inevitably followed from the conditions that were present

I agree. I think it is some kind of simple and yet as of now undiscovered principle which causes as well biological life (under such conditions as will allow this) as other arrangements into complex systems to happen. This is why I think it is a "physics issue" rather than a question which biologists are equipped to handle.
 
  • #104
Max Faust said:
I agree. I think it is some kind of simple and yet as of now undiscovered principle which causes as well biological life (under such conditions as will allow this) as other arrangements into complex systems to happen. This is why I think it is a "physics issue" rather than a question which biologists are equipped to handle.

Just one correction: I think what you're looking for is a metaphysics issue.
 
  • #105
DaveC426913 said:
First, let's define "chance" in this context. If life started by "chance" that means that, on one hundred Earths in identical conditions, it is entirely likely life would not develop on any others. It just happened to be so on this one.

That being said, the third option is that life inevitably followed from the conditions that were present. i.e. on one hundred Earths in identical conditions, all of them would develop life.

Well, certainly it raises the question what a probability for something you know has happened might be. Of course, the probability is 1. The question itself is meaningless.

Then you need to define 'identical conditions', and that is where it becomes tricky. We cannot define identical conditions. We can say how many of a billion unstable atoms will decay in a certain time frame, but we can say nothing about when a particular atom will. We can only place bets. That's a 'law' that is not time-reversible.

So either we have incomplete knowledge at present or chance is a feature of the universe. I'm inclined towards incomplete knowledge, but of course if that is right, we can't know it's right until we find out what that incomplete knowledge might be.

The multiverse solves the problem of chance, but it is hardly an economical solution. It is more like an abandoning of the problem – which may, of course, be the wisest thing to do, but I don't like that. You explain how this happened by including it in the set of 'everything that could have happened'. But it's saying the same thing as chance, really – from this point here to that point there, x possible universes can happen and they all do, so the concept of 'chance' is translated into this: given a particular event or set of events, it is the proportion of possible universes that contain the particular feature you're interested in. The 'chance' of life happening, for instance, could be calculated by looking at how many of those possible universes develop life – given that life will occur at different times in different universes, that's an awful lot of calculations, but theoretically possible, I would have thought.
 
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  • #106
Archosaur said:
I cannot put into words how strongly I disagree with this. The barrier you perceive between biology and physics, or between any two fields of study, are social constructs, not properties of the universe. Don't departmentalize that which doesn't need to be. Yes, the physics behind a cell is enormously more complicated than a system of pulleys, but can you really argue that that they follow separate rules?
They don't follow separate rules, of course. But the explanation for why a particular life form is like this and not that does not come from physics, or at least can only partially come from physics. Once you are at the level of explaining function, you are no longer at a level of physics explanation.

At the level of minimum complexity for life that follows my earlier provisional definition – apparent intention to perform those functions that are necessary for successful reproduction (a definition that certainly includes viruses as life) – you are already firmly in the realm of biological explanation if you are interested in explaining the way that the life form achieves its 'aims' (they are of course not aims at all, but as ever when talking of evolution, it is hard not to talk in these terms – hopefully you can understand this proviso, that evolution has neither direction nor purpose, is implicit).
 
  • #107
DaveC426913 said:
I think what you're looking for is a metaphysics issue.

Perhaps so... but I'm not convinced.

Parts of "hard physics" today are unquestionably metaphysical (at least thus far), such as the various shades of string theory, branes, etc., whereas it ought to be relatively simple (in the context) to formulate a simple theory for why complex systems that show negative entropy occur. What kind of mechanism is driving this tendency towards "life"?
 
  • #108
Life can be whatever ever you want it to be. We can all argue all we want about what it is and we can even come up with the most popular defintion. But the fact will remain that the definition we give was our own defintition. We can define our rules for life and then put all matter into our 2 sections, Living and non-living. But the bottom line is that we make the rules. So in the end it only matters what each person beleives.
 
  • #109
binbots said:
Life can be whatever ever you want it to be.

In that case, I want it to be something which requires no magical concept.
Whether this be "God" or "irreducible complexity" or "random fluctuations in the protein soup".
I want it to be an obvious process which originates in a basic law of physics.
 
  • #110
binbots said:
Life can be whatever ever you want it to be.

I agree, because "life" is a word. However, so is "boat". "Boat" can also be whatever you want it to be, but a long time ago, we all got together to come up with a single definition of "boat", not because there is one inherently true definition of "boat", but because words are only useful when people agree on their definitions. The word "life" isn't too far gone. Most people agree that trees are alive and that rocks are not. But now we're here to whittle down some of the fuzzy edges to create a more useful word.

Also, Sea Cow, your definition of life includes computer viruses (apparent intention that insures it's survival), which can already be completely explained by physics.
 
  • #111
Max Faust said:
Parts of "hard physics" today are unquestionably metaphysical (at least thus far), such as the various shades of string theory, branes, etc., whereas it ought to be relatively simple (in the context) to formulate a simple theory for why complex systems that show negative entropy occur. What kind of mechanism is driving this tendency towards "life"?

There is none. We (living things) are part of the drift towards higher entropy. We are organised matter, but we also consume energy and produce a great deal of heat! Overall, we life-forms on Earth are simply a part of the process by which the highly organised, low-entropy Sun burns itself out.

Oh, and is string theory "hard physics"? Quite the reverse, I would have thought. Quantum mechanics is hard physics, as is relativity, but I think to qualify as such, you need at the very least to have some predictive power.

binbots said:
Life can be whatever ever you want it to be. We can all argue all we want about what it is and we can even come up with the most popular defintion. But the fact will remain that the definition we give was our own defintition. We can define our rules for life and then put all matter into our 2 sections, Living and non-living. But the bottom line is that we make the rules.

Yes, I agree with this. Life is a category that we impose on the universe. And whatever your definition, when it first appeared will always be a fuzzy area. It's a little like asking how many water molecules you need to make wetness.
 
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  • #112
Why is everyone so seemingly hell-bent on an Aristotelian definition?

There is no trouble finding examples that are alive or not alive that we can all agree upon.

The problem is that there are examples 'left over' by this process that defy agreed classification.

Could this be because there is actually a range from definitely alive to definitely not alive?
 
  • #113
Sea Cow said:
We (living things) are part of the drift towards higher entropy.

Maybe so, but it still seems as if there are local "clusters" of "things" that come together in temporally organised structures that show negative entropy. It is this "tendency" that I want a name for. You can call it "life" (because "life" is certainly a modality of this "tendency") or you can look for a common, physical denominator - which perhaps is something akin to the way "gravity" makes "stuff" cluster together into stars and galaxies instead of "smearing" out evenly throughout the available space.
 
  • #114
Sea Cow said:
Oh, and is string theory "hard physics"?

Uh... well maybe not. I think of it as "metaphysics"... but it's still something that a lot of physicists are fervently pursuing.
 
  • #115
I know this isn't going to go down well here, but I don't think the answer to your question about the appearance of clusters of temporally organised structures lies in physics! Or at least, the answer to how the organisation in some of these structures increases over time doesn't.

It is a question at the level of biology that requires you to examine the environmental drivers behind evolution. Once you step over the line from non-life to life, pretty much however you define life, you're into this level of explanation.

It's an open question, afaik, whether there is even a tendency in evolution towards complexity. Most life hovers on or just above the level of minimal complexity required for life, and it always has done since life appeared. We more complicated forms are exceptions. The most basic forms such as bacteria and archaea are the norm.

The appearance of life in the first place, of something that could then evolve, may well be a question for physics, and you could be right that there is an underlying mechanism there. The problem with this whole question, for me, is that once you have something that you can definitely call life, you're way past that point. We're still a long way from understanding even the basics behind what happened before that point on the way to the first life.
 
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  • #116
It's an open question, afaik, whether there is even a tendency in evolution towards complexity. Most life hovers on or just above the level of minimal complexity required for life, and it always has done since life appeared. We more complicated forms are exceptions. The most basic forms such as bacteria and archaea are the norm.

Fair comment.
 
  • #117
That said, we shouldn't underestimate the complexity and organisation of bacteria!
 
  • #118
Sea Cow said:
It is a question at the level of biology that requires you to examine the environmental drivers behind evolution. Once you step over the line from non-life to life, pretty much however you define life, you're into this level of explanation.

Well, then the problem is that I really don't see any "line" here. I don't see "life" as something which suddenly manifests through a mystical process of this or that "genesis". I examine the driving forces behind "evolution" from the most fundamental level possible, which is that of physics. I will accept it if anyone can prove me wrong - which in my opinion would only imply the existence of some other "magical" principle that would lead me to simply reformulate my question - but until this happens, I'm quite convinced that there exists a fundamental law of physics that is as of yet undiscovered, having to deal with local systems of negative entropy; how they form and how long they will last (which is probably a function of their degree of complexity).
 
  • #119
Max Faust said:
I examine the driving forces behind "evolution" from the most fundamental level possible, which is that of physics.
I don't understand what this means. You can't explain why a particular trait gives an evolutionary advantage without reference to the biological context.

Could you give me a worked example of how a particular trait has evolved, for instance the duck reflex, purely with reference to physics?

Physics isn't always the most fundamental level of explanation. It depends on the question.
 
  • #120
Max Faust said:
Well, then the problem is that I really don't see any "line" here. I don't see "life" as something which suddenly manifests through a mystical process of this or that "genesis".

The line is where you choose to draw it. I agree that there's an unsolved problem considering how you get from something that definitely isn't life to something that definitely is (as a previous poster put it). That doesn't mean mystical processes, just processes we don't understand yet.
 
  • #121
Sea Cow said:
processes we don't understand yet

That's my whole premise for this thread.

I want to arrive at a deeper understanding of how "life" is emerging from non-life, without having to add any X-files factor of mystery. (I haven't even started on the problem of cosciousness yet! So far I'm only focusing on the "determinism" of proteins that are seeking together to form more complex structures. I think this is due to a process which is similar to how mass is a local phenomenon in a mostly "empty" space.)
 
  • #122
Sea Cow said:
Could you give me a worked example of how a particular trait has evolved, for instance the duck reflex, purely with reference to physics?

Physics isn't always the most fundamental level of explanation. It depends on the question.
I'm not sure you understand what fundamental means. Physics is the most fundamental level. All biology is built on top of chemistry, which is built on top of physics.

It is true that physics is not always the most appropriate science with which to answer a certain question.
 
  • #123
Max Faust said:
That's my whole premise for this thread.

I think this is due to a process which is similar to how mass is a local phenomenon in a mostly "empty" space.)

Then that is a different premise than the starting of this thread. You were looking for a simple definition; now you're looking for a mechanism for its genesis.

This now belongs in the Philosophy Forum.
 
  • #124
DaveC426913 said:
This now belongs in the Philosophy Forum.

I disagree.

I call myself a *philosopher* and I have no doubt that this issue can be debated for a million years without getting anywhere in that context, which is why I want to take it to the physicists. Is it possible to imagine a process of "clustering" that makes simple things seek together into more complex things by law? If so, it is my conjecture that "life" is just a step on this way and a purely physical phenomenon which can be derived from simple, physical laws.
 
  • #125
Is it possible to imagine a process of "clustering" that makes simple things seek together into more complex things by law?

Not while your terminology employs such bad science.
 
  • #126
*facepalm*

Never mind.
 
  • #127
Max Faust said:
...which is why I want to take it to the physicists...
It's still a philosopical question.

And welcome to the Philosophy Forum. :smile:
 
  • #128
The reason there is no workable definition of life is simple, it doesn't exist. There is no hard distinction between matter that is alive, and matter that isn't, it's a human cognitive illusion, that's why we can't define it, that is, find that distinction, because it isn't there.

Philosophy, naïve science, for 2000 years they tried to define such things as 'life' or 'a good person' or 'to be' or 'to think' or 'to be self aware' or 'to be human' and only in the last 100 years did some people finally crack the nut, the simple answer that these things cannot be defined is because they don't exist. That humans perceive a category needn't mean it exists up to rigorous objective standards. Especially if different humans perceive differently.
 
  • #129
Kajahtava said:
The reason there is no workable definition of life is simple...
The goalposts have been moved. Please see post #121 (and then 123).
 
  • #130
DaveC426913 said:
The goalposts have been moved.

Actually, no, they haven't. But never mind. I'll get around to redefine the opening question at another crossroad at another time and (likely) in another place. Thank you for your contributions though. I need to refine my language, is my closing statement.
 
  • #131
We have been through all these before

Quotes from previous replies

Unfortunately, life is not that simple!
post#6

Really this should all be in the Philosophy section.

I kind of think you have a point... except you don't.

My question is specifically about a simple definition of "life" which may be plotted into physics as a vector both on the small and the large scale.
posts #41 &42
 
  • #132
Physicists can answer your question.

"No. There is no known force or model that suggests this. Nor is there any reason to suppose so. Life follows from the physics of chemistry. Thread locked."


Now, physicists may be able to posit a more palatable answer to this - but only by taking off their physics hat and putting on their philosophy hat.

Which is why I saved your thread by getting it moved before it got locked.
 
  • #133
DaveC426913 said:
That being said, the third option is that life inevitably followed from the conditions that were present. i.e. on one hundred Earths in identical conditions, all of them would develop life.

My money is on this third option.

Is this nothing more than the Anthropic Principle?


Andy Resnick said:
I'm sorry, but this is a terribly limited view of Physics. I refuse to let biologists have all the fun (and grant money).

signed
 
  • #134
DaveC426913 said:
I saved your thread by getting it moved before it got locked.

Okay.

But I will have it explicitly known that I *dreaded* to raise this issue in a philosophy forum for reasons that I think anyone with an affinity towards the cold sobriety of physics can appreciate.
 
  • #135
Pythagorean said:
Is this nothing more than the Anthropic Principle?

Anthropic Principle? No.

You could make a vat of primordial soup and hit it with lightning until it developed the precursors to life, and ultimately life.

If you did this with 100 vats, and all 100 produced life, then the conclusion might be that life is not due to chance, that it is inevitable consequence of the conditions present.
 
  • #136
DaveC426913 said:
Anthropic Principle? No.

You could make a vat of primordial soup and hit it with lightning until it developed the precursors to life, and ultimately life.

If you did this with 100 vats, and all 100 produced life, then the conclusion might be that life is not due to chance, that it is inevitable consequence of the conditions present.

I understand what your point was, my confusion is with the anthropic principle I guess. I thought it fit the bill.

Would you state the anthropic principle for me in your own words?
 

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