I don't exactly know how to phrase the question, but it seems like most forces in the universe are governed by physical processes where entropy is constantly increasing.

Then you have Earth, where we have living organisms that expend energy to (locally) combat the forces of entropy, i.e. matter binds with itself to create structures. Although on Earth, living organisms are also subject to entropy and die and decay into smaller, more primitive constituents.

On Earth, we also have robots and technology that combat these same forces, but the work can ultimately be traced back to a life-form that initiated the process. And technically, the sun would be considered the source from whence the life-forms obtained the energy to perform the work.

I am having an extremely difficult time imagining a type of process where work is performed to create structures combatting the forces of entropy on a local scale. The obvious exception is life as it is on Earth, and it seems like the necessary antecedent.

Would all instances of processes that combat entropy in this type of scenario be considered life?

Edit: I want to tag this as entropy and universe, but I have insufficient points.

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    The definition of life is not trivial and not resolved yet. If you have the opportunity, I recommend watching lecture 14 (actually, the whole series is great) of "Mysteries of Modern Physics: Time" by Sean Carroll. In it he deals with the themes of entropy, complexity and life. His book "From Eternity to Here" also seems to touch the same subject on Chapter 9, but I haven't read it yet.
    – Koeng
    Commented Jan 3, 2013 at 6:39
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    If you allow refrigerators and other entropy-combatting devices to us in order to source it to "life", why stop there? Why not trace ourselves, not to mention our evolution, to some even more grandiose and god-like entropy-combatting force? And then trace that god's existence to some yet greater non-entropic process? What motivates any particular point for curtailing the infinite regress? Commented Jan 3, 2013 at 12:06
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    Well, I just wondered what makes 'life' a special thing to try to single out as a cause of non-entropic processes. This is precisely what you are trying to do, but it is not clear to me why one should. So it is related to your question, if only to ask why you would ask. Commented Jan 3, 2013 at 14:21
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    Personally, I think you've made a very interesting definition of life. The immune system is precisely where I see the curtailment (historically, evolutionarily) of entropy. Even if we don't know it, our consciousness forms the adaptive immune system that continues this process (it's subtle because most things we've already found solutions to and truly novel entropic forces rarely surface).
    – Marxos
    Commented Jan 4, 2013 at 5:20

6 Answers 6


Chemistry is anti-entropic.

Whether a reaction will occur or not depends on what is called Gibbs Free Energy. The fundamental equation is

∆G = ∆H - T∆S

where H is the stored energy and S is the entropy. Any reaction where ∆G is negative will proceed--which could occur because entropy goes up, or could because energy is released (heating up the surroundings). If there is no way to vent the heat, then overall entropy will go up (because of the temperature term T increasing, which will also increase S; the direct dependence of S on T is not shown in this equation which assumes T is held constant), but any system that can lose heat to the outside--and that's basically any chemical reaction--can power its way to lower entropy by expending enough energy.

A canonical example of an exothermic (∆H > 0) entropy-reducing reaction is crystallization. Solids essentially always have lower entropy than liquids. (This goes for phase changes from gas to liquid and liquid to solid, also.) But there are plenty of other examples; any reaction which reduces the number of molecules also tends to be entropy-reducing (even burning hydrogen: 2H2 + O2 -> 2H2O converts three molecules to two).

Bottom line: local reduction in entropy is not in the least exclusive to life; it is a general property of chemical systems which do not trap all heat that they produce.

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    You have answered my question entirely. But it just opened more up! So, living organisms employ metabolic processes where ∆G<0 to generate Gibbs free energy and then apply the work to non-spontaneous processes that are vital to life, where ∆G>0. Right? Commented Jan 4, 2013 at 22:54
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    @CayetanoGonçalves - All chemical reactions that move forward have ∆G<0. But in a sense, yes, living organisms have found ways to couple processes where ∆G>0 to ones with ∆G<0 so that the overall free energy decreases (this is much of the point of metabolism--sugar wants to burn, but organisms make sure that it only can when something else useful happens at the same time). Living organisms are also special in having quite a few different reactions where ∆S<0 (burning energy and dumping waste heat to the outside). It's no secret that life exploits chemistry to survive!
    – Rex Kerr
    Commented Jan 4, 2013 at 23:00
  • "Chemistry is anti-entropic"... that's absurd, what about astronomy? First, entropy only applies to systems which are subject to change (and therefore follow an entropical behavior), not to mental knowledge. Second, any systemic interaction (chemical, astronomical, or any other) can produce entropy (energy dispersion) or energy concentration. Chemical interactions are not necessarily "anti-entropic". Third, in order to point a "living force", the term "life" should be precised. There is no precise definition of life. According to multiple definitions, rocks are living entities.
    – RodolfoAP
    Commented Feb 7, 2021 at 4:22
  • @RodolfoAP - Rex Kerr's argument wasn't that chemical processes are "necessarily" anti-entropic, only that some heat-releasing reactions are. And even in this case, if you consider both the reacting chemicals and their external environment, the total entropy of both does increase even if the entropy of the reacting chemicals goes down (the heat added to the environment increases its entropy by more than the decrease in entropy of the reacting chemicals).
    – Hypnosifl
    Commented Feb 7, 2021 at 6:09
  • Thanks for the down to earth answer, recentering entropy as a thermodynamic concept, not a great mumbo jumbo about disorder and what have you. I have a question: how about exothermic nuclear reactions (fusion and fission alike)? Can they be seen as entropy reducing as well?
    – armand
    Commented Feb 7, 2021 at 6:26

The canonical counterexample is a hurricane. Like a living organism, it increases the entropy of its environment (in this case by transporting heat from the warm ocean surface to the cold upper atmosphere) in order to maintain its own, localised low-entropy structure. This structure is low-entropy in part because it involves highly correlated motions of air molecules, i.e. wind.

The similarities between hurricanes and organisms do not stop there. Another important property of organisms is that their identity remains despite the continual replacement of all the atoms that make them up. Hurricanes also have this property.

Like organisms, hurricanes are subject to an analogue of death - they dissipate when they pass over land. Although the primary cause of a hurricane's motion is the prevailing wind, there is some evidence that when the prevailing wind is subtracted, hurricanes tend to move toward regions of warmer surface water, where the conditions are better for their "survival". Hurricanes thus have a rudimentary form of behaviour.

Hurricanes also possess something analogous to an organism's anatomy: the eyewall, the fast winds near the surface, and the drier air spiralling out at the top, must all be in place in order for the hurricane to persist - yet they are all generated by the processes that comprise the hurricane itself. (The anatomy of a hurricane is actually considerably more complex than how I've described it here.)

Hurricanes are not the only example. When you start looking, you realise that although they're not everywhere, they're relatively common. Sand dunes, fire and ocean waves could all be described the same way, although they're not as nicely localised as a hurricane.

If you want, you could consider all these things to be alive. Personally, I prefer not to, but it's just a question of definitions. Still, as a scientist, the existence of these counterexamples makes me happy. It means we can learn more about life by studying these simpler, yet related phenomena. This is, essentially, what I do for a living.

  • I think this is brilliant Commented Jan 23, 2013 at 20:34
  • From the POV of Lovelock's Gaia, these are not living things, but do constitute the parts of a living thing. They are mechanisms that support an overall agenda of homeostasis. They are not themselves living because they do not adapt so as to maintain themselves. Future sand dunes will not be better at being sand dunes due to the incorporation of information from past sand dunes. He imagines that ecosystems do so, and the planetary ecosystem therefore must.
    – user9166
    Commented Sep 24, 2016 at 5:17

Would all anti-entropic forces be considered living?
I am having an extremely difficult time imagining a type of process where work is performed to create structures combatting the forces of entropy on a local scale. The obvious exception is life as it is on Earth, and it seems like the necessary antecedent. Would all instances of processes that combat entropy in this type of scenario be considered life?

No. Refrigerators cannot be considered life.
Some people think that life, contrary to the general tendency dictated by the Second law of thermodynamics, decreases or maintains its entropy by feeding on negative entropy. But the principle that entropy can only increase or remain constant applies only to a closed system which is adiabatically isolated, meaning no heat can enter or leave. Whenever a system can exchange either heat or matter with its environment, an entropy decrease of that system is entirely compatible with the second law. Like the refrigerators. Living organisms preserve their internal order by taking from their surroundings energy, in the form of nutrients or sunlight, and returning to their surroundings an equal amount of energy as heat and entropy. The apparent paradox between the second law of thermodynamics and the high degree of order and complexity produced by living systems has its resolution in the energy that enters the biosphere from outside sources. Entropy reduction is a general characteristic of life.

Recent discoveries in chemical systems show that, under certain autocatalytic reactions, non-living molecules (such as RNA) compete for resources chemical (nucleotides). Small differences in the configuration of these molecules may result in higher or lower reaction efficiency. Since resources are finite, the variant leads to less reactive to extinction. The process of Darwinian selection begins even before the emergence of life. In fact, this type of system, unlike the more common chemical reactions, is only stable when it reaches a stage of continuous changes. This is the dynamic kinetic stability, or DKS. Since the system receive power, the second law of thermodynamics is not violated, and biology becomes a particular case of chemistry. ( See What is Life?: How Chemistry becomes Biology, Addy Pross )

  • Great answer! So, are the only structures in the universe where an apparent negentropy can be observed considered life-like (RNA, virus, spider) or a consequence of life (spiderweb, laser, refrigerator)? Because to battle entropy, structures would have to be built from the microscopic level to deal with even the smallest entropy. Commented Jan 3, 2013 at 16:29
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    @CayetanoGonçalves - No, not even close. Crystal growth reduces the entropy of the molecules in the crystal. Freezing water reduces the entropy in the water molecules. Draw your boundaries right and entropy goes up and down all over the place.
    – Rex Kerr
    Commented Jan 4, 2013 at 16:20

In fact, you are proposing a definition of life.

Entropy is not disorder. Entropy is moreover energy dispersal [1]. Any systemic interaction (e.g. two containers with substances at different temperatures, or two magnets approaching) can produce negative or positive entropy. Consider that systems are not only thermodynamic, but of a variety of species: informatic, biological, emotional, etc. Entropy equivalent interpretations can be found for many of such domains.

The idea that the universe tends to a disorder, or that the entropy of the universe will get to a maximum value at the end of time is naive. Such idea is equivalent to predicting the final state of a house, when it is in the process of construction, just by observing how the hammer works. Some phenomena, like that of thermodynamic systems, usually ends up in thermical dispersal, or entropy increase. But not in all cases. There are no pure thermodynamic systems. All systems are affected by multiple types of behaviors. Benard cells might appear when a liquid enters into ebullition. Free magnets in space tend to align. Human beings are formed from dust. Etc. All such examples are the equivalent of energy concentration.

Considering that the term life has not a precise definition, you are suggesting that any interaction that produces the opposite effect of entropy (energy concentration, which usually implies organization, although not always) would be classified as life.

In such case, the existence of animals and plants would be life. But also the existence of the sun, stars, every rock in every planet, every atom, etc., would be life. At least, that would be more precise than the current definitions of life.

[1] The second law of entropy states that the total amount of change of the ratio heat over temperature is always positive or zero. In simple words, this tells that the spontaneous internal energy changes of a system tend to dispersal, not to concentration, and this can be observed just by allowing systems of different temperatures to interact exchanging temperature and assessing the final result: thermic energy flows from hot to cold, until equilibrium; in such case, the entropy change value is positive. Boltzmann provides a generalization of such principle, which can be applied to any system, although the notion is not so intuitive and might be problematic from the philosophical perspective, because it assumes everything is a particle, an object. Although atomic or even molecular entities are not precisely particles, the artifice still works.


Well, personally doubt what you already think about entropy. For a while we were told in schools and universities that the second law of thermodynamics is among the most fundamental laws of Nature. I even saw a book titled "arrow of time" which was trying to define the arrow of time by entropy increasing (or negentropy decreasing) processes toward a maximum entropy content of the whole universe: negative entropy gradient depicts the arrow of time, in the sense that a negative pressure gradient locally depicts the forward flow of a fluid, and a negative voltage gradient guarantees an electrical current and etc. But more that I read and thought about it the more I doubt about the whole issue (in the sense it is usually put forward) and finally I found out that entropy is just a measure of OUR lack of knowledge about the reality, the true order. Increasing entropy is a statistical observation (coarse graining, see here for example), not a real happening. A good question can be to ask how our epistemic knowledge can be such closely related to the real laws of Nature, so that the processes USUALLY happen in a way to reduce our knowledge about the instantaneous phase of a system? That "USUALLY" can then explain why it is not always the case and you can (though not always obviously) find a good number of events that at least locally contradict with this USUAL conclusion. Now you are asking about if local contradictions can be viewed as a definition of "life" (consciousness?) and the other guys have already answered you.



For those that believe in a Creator or God what always has been and will be the only explanation for such a creature is that it is non-entropic and that everything in the Universe is a result of the "thinking" or wish-fulfillment of this being. If the original state of the multi-verse was just pure "thought" (the elusive dark-matter we will never find) and this "thought" realized its own existence and started questioning, contemplating and desiring anything and everything beyond itself thought would do whatever it had to to "become" reality. The basic structure of anything would have matter on one side and anti-matter on the other joined and forever separated by the "thought-line" that would run through and connect everything. The Ultimate String Theory and like the old "ether" formula would satisfy a Grand Unification Theory. The reason why this hasn't been talked about or "exposed" is that while proving the existence of "God" it would also prove that "God" not only has no control or direct influence on anything once created but that in fact everything has a life of its own and creatures capable of thinking are indeed "God-like" as they can and do create their own reality as well.

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    Welcome to Philosophy.SE. Your answer seems to wind about a number of ideas very rapidly, with minimal explication or scaffolding structure. Do you think you might be able to elaborate the argument you're presenting?
    – commando
    Commented Sep 24, 2016 at 3:00

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