With that established, I then define "life" as "self-productive machinery": — Pfhorrest

Ah. But the question when it comes to life is how can a machine self-reproduce. That is the essence of Pattee's epistemic cut issue. It is the central problem that a definition of life must address.

See Pattee's account of von Neumann's famous challenge to quantum theorists....the infinite homuncular regress that arises as we try to avoid accounting for why a machine would have the intent to make the machine that it does.

The most convincing general argument for this irreducible complementarity of dynamical laws and measurement function comes again from von Neumann (1955, p. 352). He calls the system being measured, S, and the measuring device, M, that must provide the initial conditions for the dynamic laws of S. Since the non-integrable constraint, M, is also a physical system obeying the same laws as S, we may try a unified description by considering the combined physical system (S + M). But then we will need a new measuring device, M', to provide the initial conditions for the larger system (S + M). This leads to an infinite regress; but the main point is that even though any constraint like a measuring device, M, can in principle be described by more detailed universal laws, the fact is that if you choose to do so you will lose the function of M as a measuring device. This demonstrates that laws cannot describe the pragmatic function of measurement even if they can correctly and completely describe the detailed dynamics of the measuring constraints.

This same argument holds also for control functions which includes the genetic control of protein construction. If we call the controlled system, S, and the control constraints, C, then we can also look at the combined system (S + C) in which case the control function simply disappears into the dynamics. This epistemic irreducibility does not imply any ontological dualism. It arises whenever a distinction must be made between a subject and an object, or in semiotic terms, when a distinction must be made between a symbol and its referent or between syntax and pragmatics. Without this epistemic cut any use of the concepts of measurement of initial conditions and symbolic control of construction would be gratuitous.

"That is, we must always divide the world into two parts, the one being the observed system, the other the observer. In the former, we can follow up all physical processes (in principle at least) arbitrarily precisely. In the latter, this is meaningless. The boundary between the two is arbitrary to a very large extent. . . but this does not change the fact that in each method of description the boundary must be placed somewhere, if the method is not to proceed vacuously, i.e., if a comparison with experiment is to be possible." (von Neumann, 1955, p.419)

https://homes.luddy.indiana.edu/rocha/publications/pattee/pattee.html

I do like your general direction as well, however, your particular definition Suffers from including Crystal growth As a living being, because Crystal growth uses a flow of energy to do productive work upon itself (Build its more ordered lower entropy structure) So it does reduce its own internal entropy And transfers the entropy difference as he to the environment. — Sir Philo Sophia

I thought that crystals were excluded from my definition because a crystal is not in itself a machine. Crystals are lower-entropy than other arrangements of their constituent molecules, and they are produced when energy flows out of the system they are a part of (when temperature decreases). But they are just a product of that lower energy favoring a lower-entropy configuration, they are not exploiting the change in energy to do work (as they must to be considered machines), which work in turn reduces their entropy.

I think that is problematic as well because gravity does fight against the second law of thermodynamics as it reduces entropy when matter clumps up together ( less micro-states are available for the matter to explore). — Sir Philo Sophia

That is pretty much the same as my take on crystals above: the collapse of things under gravity can locally reduce entropy, and even power machines that can then reduce their own internal entropy, but that collapse itself is not life by my definition.

However, I am much more comfortable with an energy and work Framework of defining life than a nebulous/abstract and information entropy related one. — Sir Philo Sophia

I am also focusing on work as a primary factor of my definition; that's why I thought your definition was so similar to mine. The principle of least action is very closely related to entropy, such that veering away from the course least actions is basically the same thing as resisting the increase of entropy.

I've always enjoyed reading your posts on other topics so I look forward to your further thoughts and/or critique on the subject. — Sir Philo Sophia

Thank you very much, it's so nice to hear some positive feedback here, where it seems almost all of the responses are negative.

With that established, I then define "life" as "self-productive machinery": — Pfhorrest

Ah. But the question when it comes to life is how can a machine self-reproduce. — apokrisis

Please note that I didn't just mean machinery that produces other machinery like itself, but rather, machinery that does "productive" work, in the sense that I defined it in that post, upon itself.

I like that von Neumann quote, though.

I think that is problematic as well because gravity does fight against the second law of thermodynamics as it reduces entropy when matter clumps up together ( less micro-states are available for the matter to explore). So anything that uses such lines of definition I believe would not be viable. My general intuition, is that all entropy based definitions of life would be flawed. I'm still thinking through that and when I go through the Negtropic Articles And arguments that apokrisis Made, — Sir Philo Sophia

I agree that entropy accounting can be a little shonky on this score. As we dig into the details of the usual view - entropy always increases – we can see that the big picture view of cosmology says something different.

Entropy looks to increase because the Big Bang says the Universe forever expands and cools. And yet that expansion is is also gravitationally negentropic. It is building up a matching amount of energy potential.

Charlie Lineweaver is an excellent cite on the complexities of this. His publications page: https://www.mso.anu.edu.au/~charley/publications.html

If the Big Bang had stayed just a simple bath of cosmic background radiation - if its expansion and cooling had been adiabiatic rather than fractured by a succession of matter-producing symmetry breakings - then no entropy would have been added or lost.

But instead, mass did condense out to create lumps of energy density that then required dissipative structures to re-disperse back to cosmic radiation. So negentropy was produced by baryogenesis - those nebula gas clouds of hydrogen, heliium and lithium. Then entropy was liberated by the gas clouds first contracting into gravitational balls, then - happy accident - bursting into the radiant flames of fusion.

Lineweaver covers this in multiple papers, showing the evolution of the Universe as a series of steps - the symmetry-breakings that cause it to fall out of thermal equilibrium and so find itself forced to use dissipative structure to get back on track. Eg: https://arxiv.org/pdf/astro-ph/0305214.pdf

By the way, this is its own complication on any least action account of cosmic evolution of course.

With that established, I then define "life" as "self-productive machinery": a physical system that uses a flow of energy to do productive work upon itself — Pfhorrest

Please note that I didn't just mean machinery that produces other machinery like itself, but rather, machinery that does "productive" work, in the sense that I defined it in that post, upon itself. — Pfhorrest

You did say that life was "self-productive machinery" and so I mentioned the telling objection to that being a sufficient statement.

The "self" has to be dealt with here if we are going to be able to make this division between work and entropy clear as "work" does speak to there being indeed a selfish interest in play.

A machine is defined precisely by its ability – as some system of material constraints - to separate work cleanly from a flow of entropification. A combustion engine explodes petrol vapour. Heat and gases are sent out of the system as waste, while pistons, cranks and wheels are turned to serve the system that made the machine.

So in the semiotic view, mechanism is what stands between the symbols and the physics as the connection. The machine is a switch dipped in the entropic flow of the universe like a water wheel in a stream. It divides nature neatly so that there is now the work being directed inwards to the organism, and the waste being spent outwards to some environmental sink.

And the shock from biophysics over the past 20 years is how literally life depends on its molecular level machinery.

I should also point out, that it is very curious that you were initially touting an entropic definition of life as being the key defining principle ( e.g., negentropic), But when I asked you to make a concise definition you completely drop that and just focus on pettee's semiotics — Sir Philo Sophia

While on that subject, Stanley Salthe has written a bunch of my favourite papers on this point. If I am parroting anyone on the matter, it is his infodynamics.

See for instance his The Natural History of Entropy....

The story begins, appropriately enough, with the Big Bang (Layzer 1975; Chaisson
2001). The key idea is that the universal expansion has been accelerating so fast that the universe has been unable to remain in equilibrium internally (Frautschi 1982; Landsberg 1984; Layzer 1975) and it appears that it may be continuing to accelerate at present (Ostriker and Steinhardt 2001). This expansion beyond the range of possibility for global equilibration gave rise to the precipitation of matter, which might be viewed as delayed energy.

Clumps of matter represent potential energy gradients of one kind or another. Because of the Second Law, these energy gradients are intrinsically unstable and the world acts spontaneously to demolish them in the service of equilibration (Schneider and Kay 1994). And the faster the degradation, the more entropy (as opposed to useful work, which embodies some of the energy in other clumps) is produced per unit time. Gradients would originally form just from gravitation and fluctuation-driven winds and waves. Some of them, just by chance, would come to be configured in such a way as to be able catalyze the degradation of other, more metastable clumps.

But, as I said, catalyzing energy degradation requires particular relations between gradients and consumers. This fact brings information into our picture. The information is required to create energy availability in a degrading gradient —availability for work. Gradient destruction in the service of work is necessarily an informed process (Wicken 1987). For a consumer to line up with a gradient so as to set up exergy extraction, it needs to have a certain orientation and form with respect to that gradient. What is a consumer? It is a gradient feeding upon another one. But it is necessarily an informed gradient. The origin of definitive semiosis (the biosemiosis of Hoffmeyer 1993) lies in these relations, as noted already by von Uexküll in 1926 (Salthe 2001). So, what is information?

etc....

Swenson, Schneider and Kay, Lineweaver, Salthe and many more have hammered out the basics of how life and mind arise as dissipative structures with the intelligence to exploit entropic gradients. — apokrisis

You are being way too accepting and mentally comfortable with loose concepts on this subject. For example, Schneider does not point to or help with any definition of life. As stated, the closest thing Schneider says to a definition seems to be this part:
" We suggest that, in nonequilibriumsituations, systems will take advantage of allavailable means to resist the gradientsresponsible for the nonequilibrium condition.Furthermore, the stronger the applied gradient,the greater the effect that the equilibriumattractor will have on the system. Emergenceof coherent self-organizing structures are theexpected response of systems as they attempt toresist and dissipate the external gradients thatare moving them away from equilibrium."

However, that is so vague and not specific to living systems so it is practically useless. For example, nearly all the dynamic processes in the whole Earth are "coherent self-organizing structures in response to resist and dissipate the external gradients that are moving them away from equilibrium". That is what ocean currents, Hurricanes, tornados, Jet streams, etc., all are doing. So, it is all useless for an scientific definition of living matter to cite or talk about these dissipative structures.

Clearly, this is why you did not try to employ any of that feel-good philosophical jargon in your definition, which I "twisted your arm" to produce.

So, you citing these things as clear and complete definitions means that your understanding of the scientific method is clearly very limited, or you true motivation here is not scientific, but to serve your own philosophical/religious views.

You want to treat live vs death, animate vs inanimate, as dualistic categories. And so any greyness or vagueness has to be eliminated from "the holy definitions".

But my organic and semiotic perspective takes the opposite view. Definitions are pragmatic. Differences are only relative. Vagueness is how anything new could even originate as a process of symmetry breaking development. — apokrisis

did you not notice that the title of the discussion is "Scientific Definition of Living vs inanimate matter"

are you not aware that Scientific Definitions generally are never to be vague, and have the utmost goal to be black or white, and only include gray when there is a lack of theory or understanding of how to tighten the definition better. So, any vagueness or gray zones are a failing, yet still can help scientific progress as a "best working theory".

In this regard, I am only interested in forming the best Scientific Definition, which you, and Semiotics at large, have the opposite interest, goal, and world view.

Accordingly, I will be responsive to and appreciate if you could constructively critique my proposed Scientific Definition, instead of proposing I abandon my goal and go with your feel-good, arm-waving, vague ideas about philosophical hallmarks of life.

So far, this is the only constructively critique my proposed Scientific Definition you have yet made:

Lineweaver covers this in multiple papers, showing the evolution of the Universe as a series of steps - the symmetry-breakings that cause it to fall out of thermal equilibrium and so find itself forced to use dissipative structure to get back on track. Eg: https://arxiv.org/pdf/astro-ph/0305214.pdf

By the way, this is its own complication on any least action account of cosmic evolution of course. — apokrisis

I am not trying to account for cosmic evolution, so this comment is off point. Again, I will be very eager and responsive to and appreciate if you could constructively critique my proposed Scientific Definition, esp. where/if my largely basing it on the physics Principle of least action.

Tornadoes and dust devils are also borderline dissipative structures if you are trying to force a biotic/abiotic division on nature. ...
So the dead/alive distinction is very easy to apply to nature when we talk about rocks vs wombats. And becomes a suitably grey matter when we talk about tornadoes vs prions.

The cites I have given on the issue address two issues. — apokrisis

no, tornadoes are not alive, and my definition clearly excludes it, and yours says they are 'maybe alive'. as I point out, I found the whole coherent self-organizing dissipative structures to be largely useless nonsense towards making a tight Scientific Definition. Again, that is what countless natural processes do with astounding complexity building: ocean currents, Hurricanes, dust devils, tornados, Jet streams, etc., . So, again, it is all useless for an scientific definition of living matter to cite or talk about these structures.

Belousov–Zhabotinsky (BZ) reactions are a classic example of inorganic systems being able to evolve better least action paths for themselves - convection cells that transfer heat with better efficiency.

my definition does not say anything about the matter evolving a better least action paths for themselves. Please read it closely, it says:
"enact kinetic energy to avoid the path of least action in at least one environment and situation, wherein the enacted kinetic energy of the organism tends to increase the organisms total potential energy over time thereby reducing its net entropy and perpetuating its unique, non-least-action existence, by self-directed reproduction of a similarly living kind as itself, and wherein the means or goal to Self-replicate or gain potential energy is not programmed or directed by an external consciousness or entity.

So, however interesting BZ reactions are, they do not ever increase its total potential energy and does not perpetuate its existence by self-directed reproduction, and thus my Scientific Definition would exclude the BZ as being living matter.
For example, BZ reactions require a human continuously add consumed reagents to keep the wave oscillation going. So, I don't understand why you even mention it here. Again, I am only interested here in a Scientific Definition and counter examples that create problems for my proposed Scientific Definition. I await your keen input on that, which has yet to manifest, so maybe that means I've got a great "black and white" Scientific Definition here???

And becomes a suitably grey matter when we talk about ... prions

Note that prions have been shown to reproduce by non-genetic means (see below Wiki), and we can assume they do Darwinian evolution b/c their conformal shapes, as with all protein structures, do not replicate exactly and are very degenerate in their functional action. Thus, I say the prion clearly shoots down any Scientific Definition of living matter based on Petty or Semiotics- no gray zone there!
BTW, I gave you another mispelling of Pettee since it gives you some good feelings, as my mispellings are likely a Freudian slip on how little I regard his/Semiotics ideas with regard to useful Scientific endeavors.

https://en.wikipedia.org/wiki/Prion#:~:text=Prion%20variants%20of%20the%20prion,as%20%22mad%20cow%20disease%22)
Until 2015 all known mammalian prion diseases were considered to be caused by the prion protein, PrP; in 2015 multiple system atrophy was found to be transmissible and was hypothesized to be caused by a new prion, the misfolded form of a protein called alpha-synuclein.[9] The endogenous, properly folded form of the prion protein is denoted PrPC (for Common or Cellular), whereas the disease-linked, misfolded form is denoted PrPSc (for Scrapie), after one of the diseases first linked to prions and neurodegeneration.[29][72] The precise structure of the prion is not known, though they can be formed spontaneously by combining PrPC, homopolymeric polyadenylic acid, and lipids in a protein misfolding cyclic amplification (PMCA) reaction even in the absence of pre-existing infectious prions[73]. This result is further evidence that prion replication does not require genetic information.[74]

The "self" has to be dealt with here if we are going to be able to make this division between work and entropy clear as "work" does speak to there being indeed a selfish interest in play. — apokrisis

Okay, that makes more sense of the von Neumann quote which otherwise didn’t seem connected to what you were saying, which I thought was about reproduction.

In the sense that I mean in my definition, the “self” that is alive just is whatever system it is that is benefitting (entropically) from the “water wheel in the stream” (great metaphor), so long as that water wheel is in turn a part of the system in question.

The definition of life can itself be seen as a guide for where to draw the boundary of a “self”: too small and the water wheel is only powering something outside that boundary, so the boundary is not around something SELF-productive (only something productive upon something outside itself); but too large and the entropic waste products of that process are contained within the boundary too, and so the system as a whole is not productive at all, self- or otherwise.

Okay, that makes more sense of the von Neumann quote which otherwise didn’t seem connected to what you were saying, which I thought was about reproduction. — Pfhorrest

It is about reproduction - Von Neumann's influential work on self-replicating automata or universal constructors.

But you have to have a blueprint of yourself to repair and maintain yourself as well as make clones of yourself.

The definition of life can itself be seen as a guide for where to draw the boundary of a “self” — Pfhorrest

But the issue in question is how does life manage to draw its own boundaries. That is what makes symbols - semiosis - necessary.

Schrödinger made this point famously in his "What is Life?" monograph ... along with fingering the complementary part paid by negentropy.

Clearly, this is why you did not try to employ any of that feel-good philosophical jargon in your definition, which I "twisted your arm" to produce. — Sir Philo Sophia

I think you just can't follow the argument. So let's break it down.

You want to employ the least action principle to define the world of inanimate physical processes. And yet from the very first bit of your definition you introduced the error of mixing entropy and potential energy - "...resulting in a tendency of monotonic increased entropy and decreased potential energy over time."

The classical Newtonian view of the least action principle is expressed by the Hamiltonian - the symmetry that obtains in an energetically closed system where potential energy and kinetic energy form a constant yo-yo balance. The swinging pendulum story. The falling weight gains kinetic energy as it falls and that then turns into a gain in potential energy as it instead rises against the backdrop gravitational field.

That's great for one level of physics. But then physics figured out dissipative structure or far from equilibrium thermodynamics. A least action principle can still apply. But how we are modelling an open energy system where there is a flow from a source to a sink. And dissipative structure arises in-between as self-organising physical structure that can move the flow with the greatest efficiency.

That is what Schneider refers to....

Emergence of coherent self-organizing structures are the expected response of systems as they attempt to resist and dissipate the external gradients that are moving them away from equilibrium

... the way a heated plate of oil breaks into an organised structure of hexagonal convection cells.

So this is about two levels of physics - closed and then open systems. And how a general variational principle - a symmetry maths for calculating shortest paths - can be applied to both.

The whole dissipative structure story was its own big revolution of thought in the 1960s to 1980s. And naturally, the sciences of life and mind could suddenly see how this second brand of physics slotted right in as a new material foundation. It changed the game.

And so we then have the theoretical biologists who did incorporate this new physics. And began to apply the least action principle again as just the obvious way to arrive at the simplest descriptions of life as a natural system. It is equilibrium maths. You established a flat baseline - a constraint of global symmetry - and then you have two opposed values, a here and a there, as your complementary quantities scaling the departures from this baseline.

If energy is actually conserved in a closed Newtonian system, and we only seem to see the positive motion of the kinetic energy. Then when than motion vanishes as it seems to with a pendulum on the upswing, we can still keep track of the now hidden energy by calling it an accumulating potential.

Likewise, in an open system, if a dissipative structures suddenly crystallises out of nowhere and generates a lot of negentropy, we can balance that by saying there is a matching increase in entropy being produce and exported across the boundary of the system.

Biologists could then develop that accounting system so that the energy/material flows could continue to be measured with some appropriate variational maths once the extra ingredient of symbols - the whole semiotic schtick - was added to the mix.

A lot of different such models have been developed. I was pointing you towards that literature. It might be confusing, but it is all about precise definitions .... of making measurements within the appropriate theoretical framework.

Now of course, if a semiotic level of dissipative structure exists and is bound by a least action principle, that is a big problem for your definition.

Or maybe not if you realise that it is certainly not the dumb and blind Hamiltonian of Newtonian systems, nor even the dumb and blind dissipative balancing act of the self-organising structures that appear in "far from equilibrium" inanimate systems. It now has to be a new variational principle that provides the right kind of measure for a living system with a memory, a goal, some kind of mind.

Something like Ulanowicz's ascendency, for instance.

So your own definition was half-baked in being based on the idea of measuring life in terms of its ability to ignore the basic constraints of physics. You said - using vague terms like intelligence and sentience - that life can do its own thing, driven by some desire to accumulate potential energy.

That is basically a mystical claim. Or at best, a descriptional definition. Look at life and it seems to somehow defy the laws of physics! It is anti-gravitational in that it can climb stairs. And even build stairs to climb.

Practicing scientists can see what really makes a working definition. You need some closure principle to create a baseline for measurement - a universal symmetry statement such as the Hamiltonian. And then you need the two opposing forms of action that are the yo-yo symmetry-breaking departures from this baseline.

That is the simplest kind of theory you can produce. The gold standard. You can now actually go out and measure the world.

But of course, as I said, the dissipative structure revolution simply served to ground biology in the right kind of physics. Biology was also engaged in the heady business of grounding itself in the other half of the semiotic equation. It was turning to information processing concepts so as to pin down the "mind" side of living systems in measurable fashion.

Salthe's infodynamics is an example of how this works.

And generally, the whole field was energised by Shannon's demonstration that information is the other face of entropy. Physics itself was stumbling into a new information theoretic era where the Planckscale - the unified physics scale - has this "Hamiltonian" metric where entropy uncertainty and information certainty are a symmetry double act like kinetic energy and potential energy.

So there is a big game in play. And the scientists actually know its rules. They know how to construct measurable theories. They understand the actual significance of the least action principle as a way to anchor that. And there is this "double foundations" thing going on where physics itself is starting to ground itself in entropy~information - the spontaneity of fundamental chance and the continuity of fundamental constraint.

BTW, I gave you another mispelling of Pettee since it gives you some good feelings, as my mispellings are likely a Freudian slip on how little I regard his/Semiotics ideas with regard to useful Scientific endeavors. — Sir Philo Sophia

I think it says a lot about your approach to scholarship for sure. :mask:

Something to bear in mind is that the analysis of living organisms as self-organising structures, etc, is very much an objective analysis, not an existential analysis. In other words, it is an analysis that seeks to understand organisms as phenomena, and is not concerned with the question of the nature of existence from the perspective of a subject.

//ps// Lineweaver’s web page is a treasure trove. //

I'm not sure about how much of your theory I understand but in my humble opinion, there seems to be complication with "the principle of least action".

Firstly, I'm totally with you in how inanimate matter behaves in accordance with the principle of least action. The only example I know of is sphericity as a preferred shape, the reason being, hopefully for my sake, the lowest potential energy attainable for a given mass and volume. Feel free to correct me.

Secondly, consider life as composed of two parts: 1. humans and 2. non-humans. Against this backdrop take a close look at how life behaves. Your theory that life breaks and bends "the principle of least action" is accurate - even for me, someone with little training in science and math, I can make out how our behavior (some but not all) is not, from any angle, the shortest distance between two points so to speak.

Thirdly, what about the fact that (one of) humanity's primary goal, especially with the aid of science, is to be as efficient as possible and efficiency is a notion that seems related but in a backwards kind of way to "the principle of least action" - the aim being to expend the least amount of potential energy required for a desired end. This seems to fit like a glove with your theory that life violates or puts a stress on "the principle of least action" interpreted as reducing potential energy to a minimum.

Fourthly, non-human animals, since they can't think like humans, generally expend more potential energy for a given objective than not i.e. non-human animals seem to be more aligned to "the principle of least action" and that because if more energy is spent than required for a particular purpose, the net potential energy of a non-human life-forms will bottom out faster i.e. a minimum potential energy state will be attained faster than for humans.

Fifthly, given the above facts, your theory would need to account for why non-human organisms are more attuned to "the principle of least action" than humans. Your theory is, after all, saying all life contradicts "the principle of least action" but, if I'm correct, non-human organisms, because of their wasteful energy-expending-behavior, would achieve minimum potential energy states at a faster pace than humans and that's another way of saying non-human life-forms are aligned to "the principle of least action", if not relative to inanimate matter, relative to humans.

Sixthly, the only difference between humans and non-human life-forms is our brains which seems to be hell bent on devising novel and ever creative ways of preserving potential energy. Taking this a bit further, the greater the potential energy of a system, the greater the possibility of that system being the handiwork of intelligence. The highest potential energy state of the universe was, I'm guessing, the Big Bang singularity. Ergo, it must've been the work of a supreme intelligence. God???

Seventhly, I'm a bit confused here so bear with me. "The principle of least action" says that "...finding the path of motion in space that has the least value". Now, observe how potential energy is calculated for an object (X) with mass m. The potential energy of an object with mass m, PE1 = m * g * h where g = acceleration due to gravity and h = vertical (straight line) distance of m from the surface of the earth. "The principle of least action" states that X will, given there are various paths available, travel to the floor (PE1 = 0, minimizing PE1) by the shortest route (vertically, straight line) but notice that this whole notion depends on PE1 reaching a minimum (zero on the floor) and remember PE1 was calculated using h [vertical (straight line) distance].

Consider another scenario for the moment, one in which PE (potential energy) calculation is done using non-linear distance (curved paths). In the case of X, suppose its PE is calculated by a curved path distance, let's call this PE2. Compare PE1 and PE2 and PE2 > PE1 [assuming energy is proportional to distance (here h and d)]. If X now takes the shortest route (h) to the floor, the reduction in X's PE will be the smallest (h is the shortest possible distance between X and the floor) and that means X will be left with the maximum amount of PE possible and not the minimum PE possible for the change in position that X undergoes. In other words, "...path of motion in space that has the least value" has maximized instead of minimized the potential energy.

I guess what I'm saying is that minimizing potential energy as a function of "...the path of motion in space that has the least value" is baked into the idea of potential energy, calculated as it is on "...the path of motion in space that has the least value". It's like filling up your car's gas tank precisely based on the distance between your town and an unspecified destination and then being amazed (the principle of least action) at how at the journey's end your gas tank is empty.

In other words, thanks for confirming that you do not have or know of a concise Scientific Definition of Living vs inanimate matter. So, maybe science has not clearly defined it? — Sir Philo Sophia

Do you really think that people who study life have never given any thought as to what life is? Never ventured a definition? Your OP cites one definition from a dictionary - was that the extent of your research? As a scholar, you owe it first of all to yourself, not to mention your readers, to do your due diligence, rather than demanding that others do your homework for you.

A couple of simple Google Scholar searches would have given you plenty of literature on the topic, including specific proposals, reviews of past efforts, as well as general thoughts on why and how we should (or perhaps shouldn't) go about defining life - which is a question that, as a philosopher, you should probably ask yourself first.

As one example, an entire issue of the Origins of Life and Evolution of Biospheres journal was devoted just to this question. Or if you like podcasts, I can recommend Sean Carroll's talk with astrobiologist Stuart Bartlett, where they touch on these issues and discuss Bartlett's own proposal. The paper is also available: Defining Lyfe in the Universe: From Three Privileged Functions to Four Pillars ("Lyfe" is not a typo :)).

If you look at the literature, you will quickly notice a pattern: the scientists who are most interested in the definition of life are mostly astrobiologists like Barlett, and origin of life researchers - which makes sense, of course (this is to the point of why we might need a definition of life). From the origins of life perspective, you may find this recent review of particular interest: Origins of Life: A Problem for Physics (2017) by Sara Imari Walker (she was also a guest on Sean Carroll's podcast). Among its 190 references the review includes some of the names that @apokrisis has already recommended to you (but not all - which shows just how much scholarship there is on this topic).


Now as to your own proposal, I find it very puzzling, because it is actually a hypothesis masquerading as a definition: a hypothesis that living organisms have a unique ability to transcend the principle of least action. The principle of least (or stationary) action is considered to be one of the, if not the most fundamental laws of nature:

Among the more or less general laws which manifest the achievements of physical science in the course of recent centuries, the Principle of Least Action is probably the one, which, as regards form and content, may claim to come nearest to that final ideal goal of theoretical research. — Max Planck

If you were to discover that anything in our universe was not subject to this principle, you would have overturned the last two and a half centuries of physics (and not just physics). The only explanation that I can see for your matter-of-fact attitude towards your "definition" is that you are harboring some severe misconceptions about PLA, as evidenced by comments such as this:

The path of least action, As defined in physics, for any living system is simply to die. — Sir Philo Sophia

Far from dooming living systems, the PLA, alongside the 2nd law of thermodynamics may be key to understanding self-organization in our universe, of which living systems are, by some metrics, the most extreme example known to us. See for instance Chaisson, The cosmic environment for the growth of complexity (1998), Georgiev and Georgiev, The least action and the metric of an organized system (2002), Annila, The 2nd law of thermodynamics delineates dispersal of energy (2010), as well as Apo's recommendations.

And here's another:

Molecular biology is based on two great discoveries: the first is that genes carry hereditary information in the form of linear sequences of nucleotides; the second is that in protein synthesis a sequence of nucleotides is translated into a sequence of amino acids, a process that amounts to a transfer of information from genes to proteins. These discoveries have shown that the information of genes and proteins is the specific linear order of their sequences. This is a clear definition of information and there is no doubt that it reflects an experimental reality. What is not clear, however, is the ontological status of information, and the result is that today we have two conflicting paradigms in biology. One is the ‘chemical paradigm’, the idea that ‘life is chemistry’, or, more precisely, that ‘life is an extremely complex form of chemistry’. The other is the ‘information paradigm’, the view that chemistry is not enough, that ‘life is chemistry plus information’. — Marcello Barbieri

What is "information"?

This is a question I often ask in relation to the claim that life can only be understood through understanding "information" as being fundamental to it.

A key phrase that is germane to the OP:

The divide between life and matter is real because matter is made of spontaneous objects whereas life is made of manufactured objects.

The distinction being that 'spontaneous objects' can be accounted for in purely physicalist terms, whereas living organisms require the manufacturing of proteins which requires coding.

I thought that crystals were excluded from my definition because a crystal is not in itself a machine. — Pfhorrest

OK, but my definition goals are far more ambitious than yours! Note that mine covers all matter what-so-ever: "Scientific Definition of Living vs inanimate matter.... any grouping of matter or energy which "

The principle of least action is very closely related to entropy, such that veering away from the course least actions is basically the same thing as resisting the increase of entropy. — Pfhorrest

I do not think so. Just the opposite, veering away from the course least actions costs more wasted energy which means the matter will generate more heat (i.e., entropy), which eventually must be transferred to the environment of the motion.

See my comment below to apokrisis re likely fatal problem with all entropy based/focused definitions.

Indeed, I am comfortable with any stab at a black and white definition of life having its interesting grey areas. We may differ on that score. — apokrisis

The only way to then demystify that telic principle is to follow Pattee, Rosen and other semioticians. The scientific account has to be expanded so it is anchored in the duality of physics and symbols, code and process, entropy and information. — apokrisis

OK, but I showed how your proposed black and white definition of life does not work for what even you personally consider as living matter (i.e., when the virus is hijacking its host to copy itself). So, clearly, you are ideologically creating fake gray zones to fit your Semiotics belief of the world; thus, your comfort with a (much) worse B/W definition. I already showed you how the virus has no epistemic cut (i.e., Pattee is wrong), so you now have much cognitive dissonance to workout within your own mind.... You, unfortunately, have the problem that when you only have a (Semiotic) hammer at hand, every problem is a (symbolic) nail. And I've been watching Semiotics hammering away at the same problem (to little/no avail) since at least the early 90s. :wink:

I think you just can't follow the argument. So let's break it down. — apokrisis

You, and the references/articles you cited, never made those arguments, so I cannot get what you never gave. Glad you are finally articulating yourself, and finally attacking my definition directly, which is what I was asking for in my original post and (begging for?) throughout my comments with you. Thanks!

You want to employ the least action principle to define the world of inanimate physical processes. And yet from the very first bit of your definition you introduced the error of mixing entropy and potential energy - "...resulting in a tendency of monotonic increased entropy and decreased potential energy over time." — apokrisis

This is a great point to bring into critical question. Here is my reasoning for that wording: if you only follow the path of least action then you are guaranteed to lose potential energy over time (at least do to real-world energy losses; e.g., even a moon in orbit is slowly losing its potential energy as its kinetic energy (KE) is continually, in part, dissipated to heat or transferred to interacting matter), and both are a monotonic process. As for living matter, we all agree that their potential energy (PE) must not decrease over time, else they would not be able to do any work (to stay alive) b/c they would not have any excess PE available to convert into excess KE, which is needed to avoid the most KE efficient path of least action. Right? So, your only question is really about "...resulting in a tendency of monotonic increased entropy... over time"; however, even you have admitted that only living matter can, and must, continually repair itself against the 2nd law requirement that the net entropy of matter in a system is always increasing, which I tend to agree with. So, the flip-side of your admission on that is that you must agree that inanimate matter must have a "...a tendency of monotonic increased entropy... over time", as required by the 2nd law. Thus, I do not see any error as you purport. Please point out where I'm wrong,
and/or restate/clarify your concern in my above context.

Then when than motion vanishes as it seems to with a pendulum on the upswing, we can still keep track of the now hidden energy by calling it an accumulating potential. — apokrisis

it is not just an accounting gimmick as you think it. PE is real and physical reality b/c E=mc^2 tells us exactly how much the objects mass has increased when it gains the PE.

Now of course, if a semiotic level of dissipative structure exists and is bound by a least action principle, that is a big problem for your definition. — apokrisis

Not true, b/c, as I argue and point out above and before, my definition calls for and requires that living matter must have dissipative structure (be it Semiotic, or whatever) that produce more KE (thus transferring/dissipating more entropy to their environment) than would otherwise occur under PLA, and I require that PE increases, which also means that there is a net decrease in entropy in locking up the energy as potential (not in KE motion). Keep in mind, and do point out where you think I'm wrong, that saying higher KE is just another way of saying higher entropy b/c it means the matter in faster motion is exploring more microstates per unit time, thus the system has higher entropy.

Or maybe not if you realise that it is certainly not the dumb and blind Hamiltonian of Newtonian systems, nor even the dumb and blind dissipative balancing act of the self-organising structures that appear in "far from equilibrium" inanimate systems. It now has to be a new variational principle that provides the right kind of measure for a living system with a memory, a goal, some kind of mind. — apokrisis

See my argument below about why I do not believe "the right kind of measure for a living system " will be based on entropy.

Practicing scientists can see what really makes a working definition. You need some closure principle to create a baseline for measurement - a universal symmetry statement such as the Hamiltonian. And then you need the two opposing forms of action that are the yo-yo symmetry-breaking departures from this baseline. — apokrisis

I am a scientist, and I think you are misunderstanding "definition" here to be a causal theory, law or formula. Please keep clear in mind that my proposed definition of living mater is not meant to measure the degree or causal dynamics of a living system, only that a living system is present. So, your counterpoint here is moot, as the goal here is not to create a baseline for measurement. Instead, as I'm sure you know, the first job of scientific inquiry is to accurately define terms, at least to the binary (B/W) level to define the minimum observable properties of the class, and how to categorize something as belonging to that class or not. In that way, my definition has closure, in that if the matter/system has the properties/dynamics which I call for then it belongs to that class of living.

That is the simplest kind of theory you can produce. The gold standard. You can now actually go out and measure the world. — apokrisis

again, not (yet) proposing a theory here. again, before theories come broad definitions which set the metes and bounds and framework from which theories may be motivated and formulated. So, I think you are way jumping the gun, and should please focus on the merits, or not, of my B/W classification definitions.

And generally, the whole field was energised by Shannon's demonstration that information is the other face of entropy. Physics itself was stumbling into a new information theoretic era where the Planckscale - the unified physics scale - has this "Hamiltonian" metric where entropy uncertainty and information certainty are a symmetry double act like kinetic energy and potential energy. — apokrisis

what do you mean by "entropy uncertainty "? The entropy in quantum mechanics (Von Neumann entropy) is zero during the pure quantum state. So, it seems to make no sense to talk about quantum "entropy uncertainty ". Are you talking about a non-pure state having a density matrix and non-zero Von Neumann entropy? However, that still would not be uncertain entropy. Please clarify.

I should point out that even for pure quantum state systems with no entropy they still have to collapse according to the classical PLA path (per QED).

They understand the actual significance of the least action principle as a way to anchor that. And there is this "double foundations" thing going on where physics itself is starting to ground itself in entropy~information - the spontaneity of fundamental chance and the continuity of fundamental constraint. — apokrisis

I do not expect that any complete and accurate broad B/W definition to classify a living system will be based on entropy. Generally, IMHO, the problem with all entropy based definitions of life is that it is possible for matter to gain potential energy during PLA dynamics without changing or increasing environmental entropy. Thus, matter can have the ability to gain future action potential w/ no change of entropy, and because all living system must gain future action potential to have the ability to create the excess KE to afford to deviate from PLA. So, if your measure is entropy change then such matter could selectively take a deviant path from nature's PLA, yet your entropy based definition would never detect it is actually alive. A virus is a great example of what I mean. Throughout the virus' whole existence "life" at no point is it increasing the entropy of the environment, even while morphing itself to attack and evade all the host's defenses, even while guiding and morphing itself to break through the cell wall, even while it guides and morphs itself to get into the nucleus (etc.), even while it is hijacking the replication machinery (thus all hidden from entropy based definition ), and not until it actually starts making copies of itself does it even potentially show up on the entropy based definition radar, but even then it is arguable that making copies of itself does not increase entropy because there are deletion of (molecular) bits, just rearrangement of existing ones that make its kind vs the host's kind (thus neutral entropy).

Hence, I choose to avoid entropy like the plague! Instead, my PLA and PE based definitions would detect the virus as being living matter the moment it takes a different path than, for an imperfect example, a similarly sized dust particle would when entering the host.

I look forward to anything that finds/establish real problems with my PLA and PE based definitions, as I'm not easily going to switch to entropy and definitely not switching to symbols in any case.

TIA!

Fifthly, given the above facts, your theory would need to account for why non-human organisms are more attuned to "the principle of least action" than humans. Your theory is, after all, saying all life contradicts "the principle of least action" but, if I'm correct, non-human organisms, because of their wasteful energy-expending-behavior, would achieve minimum potential energy states at a faster pace than humans and that's another way of saying non-human life-forms are aligned to "the principle of least action", if not relative to inanimate matter, relative to humans. — TheMadFool

good instinct. This definition I'm posting here is a small part of a broader, all encompassing theory I am formulating. My, current, broader theory would answer you here by saying that the more intelligent the matter/system is, it necessarily, on average, must deviate greater from PLA when acting on the greater intelligence, b/c, in my definition of intelligence (to come in a future post along with many other definitions) greater intelligence is just another way of saying to be able to simulate more likely outcomes further out in time and space, which would guide local actions to be proportionately more costly to achieve ever greater future PE gains. Think of intelligence as being able to see past a distant hill to a a hi PE reword goal that PLA completely blocks you from getting to, but intelligence figures out how to get there greatly deviating from PLA at very high current cost (the further out that goal is over ever higher hills, i.e., the greater the intelligence, the ever greater the cost), whereas more limited in scope creatures will follow PLA much more often, thus will do much more efficient local work more often, at the cost of attaining much less PE gains vs net KE expenditure, over time.

another factor to consider is that research has found that all that is needed for life to want to exist is that they can barely exist (no need to thrive). So, nature may tend toward lower intelligence unless competition is so high, and/or local resources are so low that it pays to get smarter to go completely against the PLA river like the salmon...

I hope this satisfactory addresses your question/concerns.

thanks for your great comments and ideas!

given that you are in such great command of current state-of-the-art scholarship on the subject, as you claim to be aware of, then why don't you reply with what you find to be the best scientific definition of what minimal properties constitutes living matter vs inanimate?

If you cannot offer one, your own or what you believe in the most from literature, then I choose to ignore your rants about me not posting literatures best vs Webster's. You should read all the comments on this discussion and you will see that apokrisis cited what he believes to be best state-of-the-art scholarship on the subject, and, while many good points were made, I found and argued how my definition performs better. and, I find apokrisis to be extremely well read, informed, and intelligent on the subject. So, let's see if you can do better... I'm all ears...


I'll address your critiques next.

Far from dooming living systems, the PLA, alongside the 2nd law of thermodynamics may be key — SophistiCat

that is an ignorant comment. You clearly do not get any of it, because I'm saying exactly the opposite! You need to better read my OP and subsequent comments before you yap off at the mouth with such nonsense dribble...

The distinction being that 'spontaneous objects' can be accounted for in purely physicalist terms, whereas living organisms require the manufacturing of proteins which requires coding. — Wayfarer

interesting idea; however, see my comments above re how my proposed definition says a virus is living matter. That said, in principle, as far as I understand, a virus requires no coding to manufacture any complex functional proteins. They may just have a simple lipoprotein sheath and some surface shapes for lock&key entry. Moreover, a virus uses a living cell's machinery to make itself anyhow, so that would make you think a virus is pure information. Yet, it is, in my estimation, physical functional information in the form of a molecular program state-machine. So, not sure how you would make an information-based definition. any proposals? and, what worse, how would you know it when you only see it from external behavior?

I should mention that, in my definition, all information (incl. coding manufacturing) is comprised within the PE aspect of the definition. So, maybe I've got that covered good enough???

as far as I understand, a virus requires no coding to manufacture any complex functional proteins. — Sir Philo Sophia

Well outside my knowledge of biology, but an encyclopaedia entry notes that ‘The simplest viruses contain only enough RNA or DNA to encode four proteins. The most complex can encode 100 – 200 proteins.’

In any case Marcelo Barbieri’s essay is very interesting in its own right, and also relevant to the OP, although perhaps only tangentially related.

OK, but my definition goals are far more ambitious than yours! Note that mine covers all matter what-so-ever: "Scientific Definition of Living vs inanimate matter.... any grouping of matter or energy which " — Sir Philo Sophia

Are you differentiating “animate vs inanimate” from “living vs nonliving”? I took them to be synonyms for our purposes, in which case a definition of life also divides all matter and energy into those systems that meet that definition (living or animate) and those that do not (nonliving or inanimate).

veering away from the course least actions costs more wasted energy which means the matter will generate more heat (i.e., entropy), which eventually must be transferred to the environment of the motion. — Sir Philo Sophia

That’s just another way of saying that to veer away from the course of least action requires an energy source and a waste energy sink, i.e. an energy gradient to exploit, which are also exactly the conditions in which locally reducing entropy is possible.

The universe as a whole always takes the course of least action and always increases in entropy, as those are almost synonyms; but having an exploitable energy gradient makes it locally possible for a limited system to run counter to that trend.

Are you differentiating “animate vs inanimate” from “living vs nonliving”? I took them to be synonyms for our purposes, in which case a definition of life also divides all matter and energy into those systems that meet that definition (living or animate) and those that do not (nonliving or inanimate). — Pfhorrest

yes, synonymous and covers energy which is carried by the matter.

i.e. an energy gradient to exploit, which are also exactly the conditions in which locally reducing entropy is possible. — Pfhorrest

in many cases this is a plausible model that is contemplated; however, the hypothesis behind my proposed definition is much broader than that and does not necessarily always require a local entropy gradient to exploit when the living mater has already accumulated excess PE (possibly by initially exploiting a local energy gradient). Once it has excess PE then it can "redirect or enact kinetic energy to avoid the path of least action" as recited in my OP definition. This is why I like the PE focused model b/c entropy gradients are not always needed along and given stretch of the organisms path (e.g., just has to burn excess PE until it finds more PE it can accumulate or find entropy gradient to exploit to get PE).

but having an exploitable energy gradient makes it locally possible for a limited system to run counter to that trend — Pfhorrest

as mentioned above, I think it is more complex that that one (maybe most common at lowest life forms). So, I'll offer my analysis and basic mechanics of how my definition/hypothesis might apply to the virus matter. It is what I wrote on the fly (first thoughts), so it is raw, and likely has many kinds of errors, yet should convey the gist of what I generally mean. Including typo/gramo errors by my dictations software. I have not taken the type to proof read it:

That is, if we consider a virus organism as an example, it appears to be an inanimate grouping of molecules until it is in the presence of an environment which activates its complex molecular action to be attracted to and mate with living cells that are hijacked to make copies of itself, whereby the virus is leveraging the potential energy gained by the living cell to carry out all the kinetic energy mechanisms necessary to move and replicate the virus. Once a copy or version of the virus is made the virus as a unique entity has effectively increased its potential energy at the expense of the living organisms reduction of its potential energy. In this way, the virus has a complex context dependent molecular potential energy program which is capable of redirecting natural path of least action forces present in certain environments towards path and destination which makes its molecular program with another organism’s molecular program replication machinery that is powered by the other organisms potential energy. Because the virus has no means to consume energy producing matter (i.e., cannot eat something to increase its potential energy so that it can produce its own goal-directed kinetic energy) it must instead systematically and smartly redirect environmental least action forces through a sequential molecular program that manipulates and redirects those forces like a gliding plane with no engines that glides to and safely lands on its target by simply dynamically adjusting its control services to create its own path of least action towards meeting its target destination which completely diverges from the path of least action which nature (i.e. gravity) would have forced the agent to take had the agent not had any such control surfaces or context dependent controlling program. In this way, according to the foregoing definition, the virus particle is indeed alive and the minimal form of life that can exist because anything less would not be able to acquire and redirect potential energy from its environment to increase its own potential energy. I posit that a virus using a cell’s machinery and PE as a tool to make copies of itself is an increase in the virus’ PE because all the viral copies share a common meaning a purpose of the original virus organism thus it has amplified itself and its kinetic action potential to affect its environment according to effective implied purpose of the common molecular program, much like any social/pack animals increase their PE by cooperating with each other in common purpose and behavioral (re)action.

yes, synonymous and covers energy which is carried by the matter. — Sir Philo Sophia

Okay good, so we agree on that front.

does not necessarily always require a local entropy gradient to exploit when the living mater has already accumulated excess PE — Sir Philo Sophia

Having a store of potential energy is the same thing as there being an energy gradient to exploit. For example if your store of potential energy is a hot or high-pressure volume of gas, that you can use to do work by releasing it into the environment, it is the temperature or pressure differential between the volume and the environment that enables the release of that potential energy; if the environment was just as hot and high-pressure as the inside of the volume of gas, it would not be usable potential energy, relative to that environment.

Conversely, if you had a cold or low-pressure volume of gas, relative to the surrounding environment, that local absence of energy would make the energy of the environment "potential" relative to the volume: you could use an internal cold sink to force the environment to do work for you.

Similarly, lifting water above the surrounding ground is what lets you get work out of it when it flows back down; if the ground was all the same level as the water, the elevation of the water would be useless. Unless, of course, you then dug out the ground below the level of the water, in which case there would then be a difference, and you could let the water flow down into the hole you dug, and use that to do work.

The absence of such a differential is the same thing as the presence of entropy, so "increasing its store of potential energy" is the same thing as "reducing its local entropy".

given that you are in such great command of current state-of-the-art scholarship on the subject, as you claim to be aware of, then why don't you reply with what you find to be the best scientific definition of what minimal properties constitutes living matter vs inanimate?

If you cannot offer one, your own or what you believe in the most from literature, then I choose to ignore your rants about me not posting literatures best vs Webster's. — Sir Philo Sophia

You missed my point. This wasn't about showing how much more I know on the subject. Although I happened to know a little more than Webster's definition, the point was to show you that voluminous literature on the subject exists and is readily available, so you don't need to start from scratch. I even gave you some specific pointers. But that was because I mistakenly assumed that you may be interested in learning and discussing ideas.

So, let's see if you can do better... — Sir Philo Sophia

Ah, no, thanks. You are not worth my time.

Having a store of potential energy is the same thing as there being an energy gradient to exploit. — Pfhorrest

I don't think so. There is no energy gradient towards the potential energy of matter. For example, where is the energy gradient towards the potential energy stored by an apple?

I think you are mixing up entropy gradients, which everyone talks about as needed to do work, and energy gradients. The two are largely unrelated.

For example if your store of potential energy is a hot or high-pressure volume of gas, that you can use to do work by releasing it into the environment, it is the temperature or pressure differential between the volume and the environment that enables the release of that potential energy; if the environment was just as hot and high-pressure as the inside of the volume of gas, it would not be usable potential energy, relative to that environment. — Pfhorrest

again, you confound your entropy gradients and energy gradients, which has you getting stuck into a single line of reasoning. Entropy math and principles only applies to statistical mechanics ensembles of particles operating near equilibrium, like gasses, not few body mechanical systems like a rock about to fall of the edge of a cliff.

Similarly, lifting water above the surrounding ground is what lets you get work out of it when it flows back down; if the ground was all the same level as the water, the elevation of the water would be useless. Unless, of course, you then dug out the ground below the level of the water, in which case there would then be a difference, and you could let the water flow down into the hole you dug, and use that to do work. — Pfhorrest

per my above, entropy does not apply to few body mechanical systems like this example, as the water molecules are all bounded in a container that limits their microstates and are in equilibrium, so cannot do work; hence, adding KE to lift them up a potential gradient did not change their entropy, nor did it change any entropy of the closed system. All you are doing there is converting KE into PE, minus dissipative/frictional losses dissipated as heat.

The absence of such a differential is the same thing as the presence of entropy, so "increasing its store of potential energy" is the same thing as "reducing its local entropy". — Pfhorrest

I don't see this a true, per my above. Your consideration of my above apple stored potential energy example will hopefully clarify that. There is no energy gradient to exploit for work to power you towards the apple, and you cannot exploit any potential energy stored by an apple b/c it is stored as potential chemical energy so requires you poses chemical means to release and use it for your own work. Same idea as nuclear potential energy locked up into all matter, you generally need nuclear forces acting means to release and use it for your own work, as in a nuclear bomb chain reaction. Otherwise, that matter w/ stored PE is not useful for work. This is where living beings get there advantage to exploit far more energy than the universe otherwise allows PLA access to, and the more intelligence the living being has the more effective it will be at finding and accessing stored, and locked up, PE, which requires paying much higher upfront KE costs to avoid PLA to get the massive locked up, PE gain. Now, local entropy gradients do help bootstrap that process when the living being has little/no intelligence or means/access to locally stored PE; however, entropy, or even energy, gradients is by far not the most important part of the life story, IMHO.

My definition hinges on the physics concept of a "machine", which is any physical system that transforms energy from one form to another, which is to say it does "work" in the language of physics.

I propose the definition of a property of such physical work, called "productivity", which is the property of reducing the entropy of the system upon which the work is done. — Pfhorrest

BTW, I should point out another major problem with your proposed definition is that it defines the whole universe as living. That is, the physical rules of the universe by default produces stars and planetary systems, which your definition would define as living b/c they were produced by the universal "machine". A star is a machine that "that transforms energy from one form to another, which is to say it does "work" " in producing radiation and new types of atoms. Likewise, a planet "uses a flow of energy to do productive work upon itself, which is to say, to reduce its own internal entropy (necessarily at the expense of increasing the overall entropy of the environment it is a part of. Mars was doing this for millions of years before its dynamic core ran out of energy and the planet "died". Earth is still doing this today, and even if all life never existed still would do it b/c the Earth has a huge and active dynamic core of energy and the planet must use and dissipate that energy to build new and ever more complex chaotic & dynamic structures to dissipate that entropy/energy, and this keeps the Earth far away from thermal equilibrium with the space it 'lives' within. That is what mountain formation, ocean currents, weathering, Hurricanes, tornados, Jet streams, planetary magnetic shields, etc., all are doing. So, stars + planets systems have all the functions/behavior of a living cell systems under your and apokrisis' definition approach. Maybe you can refine your definition approach to avoid this undesirable problems? That said, I believe my PLA/PE approach is the most fundamental and should avoid all known problems.

cheers!

Ah, no, thanks. You are not worth my time. — SophistiCat

likewise. To get more constructive outcomes, hopefully, you learn how to be more constructive in offering useful critiques. bye bye...

Having a store of potential energy is the same thing as there being an energy gradient to exploit. For example if your store of potential energy is a hot or high-pressure volume of gas, that you can use to do work by releasing it into the environment, it is the temperature or pressure differential between the volume and the environment that enables the release of that potential energy — Pfhorrest

I should also point out another argument I have against calling work potential of any statistical mechanics ensembles of particles as "potential energy", as I pointed out above PE is real and physical reality b/c E=mc^2 tells us exactly how much the objects mass has increased when it gains the PE. So, I would argue that if the mass of the particles did not decrease then they lost no energy, incl. no PE, as their entropy naturally increases toward maximum (thermal equilibrium) per 2nd law.

There is nothing about 2nd law entropy that implies that the net energy (e.g., the macro-state of temperature) of the particle ensemble system has to change for the entropy of particle ensemble system to increase or not change. Thus, any entropic gradient can always be reduced to zero (thermal equilibrium) without changing the net energy of the system and, indeed, without doing any work on matter outside of the particle ensemble system. Hence, there is no change of potential energy involved.
It is properly called 'free energy' or 'negenergy', or "work potential", but not "potential energy". To get any useful work out of any entropic gradient you have to redirect and capture the net KE of the particle ensemble system as they move towards max entropy, and redirect it towards useful work instead of just the work/heat of randomly spreading the particle ensemble to explore all their available microstates.

So, I would argue that if the mass of the particles did not decrease then they lost no energy, incl. no PE, as their entropy naturally increases toward maximum (thermal equilibrium) per 2nd law. — Sir Philo Sophia

A hot volume of gas does actually weigh more than a cold one per E=mc^2. Mass is not just in elementary particles but in the interactions between them; in fact most of the mass if ordinary matter lies in the chemical bonds between atoms, electrostatic bonds between electrons and nuclei, and nuclear bonds between nucleons and between the quarks inside them. The remainder comes from interaction with rhe Higgs field.

A hot volume of gas does actually weigh more than a cold one per E=mc^2. — Pfhorrest

sure, but that completely does not address what I said about:
"There is nothing about 2nd law entropy that implies that the net energy (e.g., the macro-state of temperature) of the particle ensemble system has to change for the entropy of particle ensemble system to increase or not change. Thus, any entropic gradient can always be reduced to zero (thermal equilibrium) without changing the net energy of the system and, indeed, without doing any work on matter outside of the particle ensemble system."

So, your response seems to be off point.

See here for details on entropy and work done in Isothermal processes:
https://en.wikipedia.org/wiki/Isothermal_process#Entropy_changes

notice how T of the gas (thus it's mass) is constant but work was done and entropy changed. Thus, PE of the gas particle ensemble is not defined by or dependent on its work done or its entropy. In fact, any work done by the gas only requires adding heat to the gas to keep its T constant, and we know that added heat only goes to maintain the KE of the gas molecules, b/c only gas molecular KE motion defines temperature, not any PE. So, that is another way to argue that no change of PE is involved.

Please reframe your example "store of potential energy in a hot or high-pressure volume of gas, that you can use to do work by releasing it into the environment" to make sense in the above context.