How does philosophy define life? And how does it overlap and contrast with the concepts and nuances of other sciences such as biology, chemistry, physics and mathematics, and how has it been influenced by advancements in these fields?

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    The problem is my colleagues biologists don't seem too "thrilled" about it either and the most frequent (I know from personal experience) answer I get is-"This is problem of philosophy, because definitions are philosophical, not scientific problem." There it stops! Any further investigation is up to this point. Then philosophers say, well, it really depends on what biologists have in mind when talking about cells, bacteria, viruses and so on and here you go............mery go round between the department of philosophy and the department of biology! The story of my life! Mar 16, 2017 at 18:38
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    Of course, take the "classical" work of Cleland and Chyba on the subject- link.springer.com/article/10.1023/A:1020503324273 .It should be a good "introduction"as to why we can't define life. Then, see the work of Lazcano, Morange and Tirard here-ncbi.nlm.nih.gov/pubmed/21162680 and there is one more recent good article about the problems various definitions of life have here-quod.lib.umich.edu/p/ptb/6959004.0006.001/… .I hope you can get at least "a glimpse" on the problem from these papers. Mar 16, 2017 at 18:53
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    The problem is in the realm of semantics. The word life has too many meanings. Might you be wondering about conscious life, sentient life, or soul life? Mar 16, 2017 at 19:36
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    One approach I have used for this is to turn the question around using pragmatism. If I were to declare "this thing is alive," or "this thing is not alive," how would that change how you treat that thing? The more you are willing to give up to treat that thing well because it is alive, the more careful you have to be with a definition of life. Once you're comfortable with the coarse grounds provided by pragmatism, then it makes sense to delve into the finer details of philosophy to fine tune that definition.
    – Cort Ammon
    Mar 16, 2017 at 19:37
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    Comments are not for extended discussion; this conversation has been moved to chat.
    – user2953
    Mar 17, 2017 at 6:42

5 Answers 5


This question was put by me with the purpose of finding the answers that is more unanimous between philosopher of philosophy as well as philosophers and scientist of biology, physics, chemistry, maths, etc (if any others). I would say it was an effort to find a specific definition which if existed and made sense would make us all happy and enlightened for a moment. But, the more you answer, more questions do come up. And, it's the virtue of the matters in philosophy to be open ended in nature, no matter how much you fill in there is more to fill.

This answer I am writing is not an answer but an amalgamation of my opinions with other agreeable and non-agreeable phrases, more like a mosaic of thoughts which may connect and contrast. Plus, I am not adding any sources as of now and will make edition to this answer as I progress.

When I asked, "What is a philosophical definition of life?" I was commented by saying "I am not too specific" because SE is a forum which promotes one answer at the end of the day. So, I changed to "What is modern philosophical definition of life?" By, modern I mean what is the contemporary consensus we have reached upon to define life, based on the evidences from science (all fields).

Before, we even find the modern philosophical definition we need to explain what was the classical definition of life?. Would you say the classical definition of life was of all the things God created the supreme thing that was created is life. I think this might be more acceptable in religious context, but I think this definition has failed to gratify more people today than ever before. Or, in the modern context would you say, "life is something that is conscious about it being". And, this doesn't simply apply to human but also to bacteria, because they do respond to several perturbations.

Or even in more modern context would you say, "life is the product emerging out the process of natural selection." And, yes it does apply to every life that is on earth.

Or, mathematically would you say, "life is a very special number which creates another value of it's own kind in that series". But, other field of science can equally contrast it by asking, "Do numbers really exist?"

While the scientific definitions between biology, chemistry, physics and maths may vary. But, science wraps all around life being described as a phenomenon emerging from the ordered and patterned influx and outflux of matter and energy, which can be read using the tools of biology, chemistry, physics, and maths alike. So, is this the modern philosophical definition, I don't' know.

I would finally say, "life is a phenomenon where the entity living it has the voluntary and involuntary knowledge of it's existence".

This is the answer I have settled for today. But, I think there is more to know about the life. What if the evidences we collect from mission on Mars and beyond our solar system totally changes our perspective of life. So, at the end I think there is a need to talk more about this question rather than just settling on one answer that looks too good.

  • If you are looking for a consensus you won't find any, there is no "modern philosophical definition". An influential view of Cleland-Chyba is that it would require a new discovery:"It is possible that in the future we will elaborate a theory of biology that allows us to attain a deep understanding of the nature of life and formulate a precise theoretical identity for life comparable to the statement ‘water is H20.’ In the absence of that theory, however, we are in a position analogous to that faced by someone hoping to understand water before the advent of molecular theory".
    – Conifold
    Mar 22, 2017 at 3:13

Life is the only form of organization of matter where structure univocally determines function and vice versa.

It means a living being is something whose organization (e.g. structure) is build upon the need for this organization to harbor processes whose ultimate goal (hence Life always exhibits a goal-oriented behavior) is to ensure the preservation of that very organization. Unlike machines or memes Life can exist only as a continuous process in the material realm and only that kinds of organizations able to produce structures consistent through time and space by the ability to sustain themselves by the influx of external influences (be it matter to sustain their organization, energy as electromagnetic radiation to "power" themselves or information to direct their behavior) can conform to the definition of living organisms. It means a machine can't be a living organism even if it's capable of reproduction because its structure isn't necessarily dependent on the influx of raw materials to sustain itself. This machine would have to be able to not only reproduce itself but also to has the need of consumption of external materials to mere sustain its own organization, which isn't what the definition of a machine intrinsically includes but this definition of a living organism does. In the same view memes can't be living organisms because they aren't in a material realm, although they do indeed require their constant reproducing in behavior in order to "survive" as entities. Only these structures which are both able to keep their organization by the very processes sustaining the structure and are consistent through space and time as long as the influences their require from the environment to sustain their structure are present can be called alive and constitute a living organization. So, basically Life is a self-organizing machine whose organization is being kept by the very same processes it keeps continuing through its existence.

Thus, we need to synthesize knowledge from various fields to build a true and genuine clear-cut definition of Life and this is how we should proceed to define Life-build upon all of our knowledge of the natural world to define the category, not only just a small fragment of it which is our knowledge of present day biology and the sciences associated with Life as we know it. But this is of course a huge mindset jump for science because it requires an enormous enlargement of the base facts derived from biology has to do to all other areas of research in all other fields and in my mind it's the role of philosophy to fascilitate it because only it can guide science into areas it can't go on its own and bring to it results only its methods can provide even where the scientific knowledge is too small to cope on its own! How about that answer?


The SEP article on life is pretty comprehensive.

How does philosophy define life?

This is an open question, and there's more than one way of defining it. From the article:

There have been three main philosophical approaches to the problem of defining life that remain relevant today: Aristotle's view of life as animation, a fundamental, irreducible property of nature; Descartes's view of life as mechanism; and Kant's view of life as organization, to which we need to add Darwin's concept of variation and evolution through natural selection (Gayon 2010; Morange 2008). In addition we may add the idea of defining life as an emergent property of particular kinds of complex systems (Weber 2010).

For your second question:

And how does it overlap and contrast with the concepts and nuances of other sciences such as biology, chemistry, physics and mathematics, and how has it been influenced by advancements in these fields?

There are several responses to this, again the article covers a lot of territory, but I would like to point out one particular case where the overlap between the philosophical concept and concepts from modern science have had and immense impact on contemporary thinking. Erwin Schrodinger, one of the founding fathers of Quantum Mechanics, wrote a book called "What is life?". In it:

Schrödinger wondered how it could be that there could be sustained order in the molecules responsible for heredity when it was well known that statistical ensembles of molecules quickly became disordered (with increased entropy as predicted by the second law of thermodynamics). The problem of heredity then was reformulated at the molecular level as to how order could give rise to order? The other main topic that concerned Schrödinger was the thermodynamics of living things in general, that is, how could they generate order from disorder through their metabolism? It was through answering these two specific questions from the perspective of a physicist that Schrödinger sought to answer the big question, what is life?

It was the answer to the first question that captured the attention of the founders of the new biology. Schrödinger argued that the molecular material had to be an ‘aperiodic’ solid that had embedded in its structure a ‘miniature code.’ That is, the pattern of constituent atoms comprising the molecule of heredity would not have a simple periodic repetitive order of the same constituents or subunits, but rather would have a higher-level order due to the pattern of its molecular subunits; it was this higher-level but aperiodic order that would contain the coded information of heredity. The elucidation of the structure of DNA and the explosion of our understanding of molecular genetics has eclipsed the other, but to Schrödinger equal, arm of the argument, namely that the most important aspect of metabolism is that it represents the cell's way of dealing with all the entropy that it cannot help but produce as it builds its internal order, what Schrödinger termed ‘negentropy.’

So Schrodinger ideas, and their subsequent confirmation by Watson and Crick, seem to support the Kantian approach to life as organization, but more importantly, has become one of the main arguments in favor of reductionism and even materialism, in the sense that it showed that something as complex as life might be eventually explained in terms of basic physics, and giving strong arguments against dualist and vitalist conceptions of life and of mind.

  • @YordanYordanov: Please refrain from extensive comments. Comments are not for extended discussion; this conversation has been moved to chat.
    – Philip Klöcking
    Oct 14, 2017 at 6:47

I suspect this question is too broad, as philosophically speaking, one could approach the phenomena of 'life' from many different angles, and conclude with many different definitions. In general, though, how you define something depends on the context in which you want to define it.

For instance, in biology we define life (roughly) as material entities with metabolisms and a few other properties. This is a definition aimed at understanding how living things work.

But if we wanted to move over to ecology we could define life in the context of it's relationship with it's natural environment, which would give us a different picture.

Or if we moved to physics, again it would be a totally different definition and perspective.

Similarly, different strands of philosophy (although I'd argue the above are also strands of philosophy), should be able to define life under different frameworks. So if you want a concrete answer, you need to be more specific.

  • I don't think the question is broad. The problem is that a question might seem broad at first, but when you start thinking and discussing about it, you realize there is a specific demand for a specific answer. If you look into the second part of the question, you can see how I am asking the question. Overall, the point is how does a philosophical perspective of life overlaps &/or contrasts with the scientific definitions of different fields. Its obvious that this question leads to an open-end answers and lots of A2A. But, that's the whole point - brain tease and synthesis of a philosophy. Mar 17, 2017 at 17:24
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    "It's obvious that this question leads to open ended answers and lots of A2A" .. that is the exact definition of a question that is 'too broad' for the Stack Exchange format. It's not a bad question in itself, but questions posed on Stack Exchange should have specific, measurable answers. People on the philosophy stack may sometimes not have picked that up, though, as this Stack community tends to be more lax on rules.
    – Cdn_Dev
    Mar 17, 2017 at 17:27
  • I think its the virtue of matters on philosophy to have an open ended answers. Because, in philosophy what matters most is the observation and the explanation of that observation based on human experiences (either personal, or with and of other persons, and/or of the existing phenomenon in the natural world) and imagination which are abstract and both possible and impossible. Most of the time human experiences are common but are also totally different depending upon the culture, upbringing, role models and or the history the person is born in (today vs. 1000 BC, 1400 AD, etc.). Mar 17, 2017 at 17:32
  • I don't disagree with you. There are some questions that are better posed on open ended forums, rather than Stack. In general, a question that's appropriate for Stack should have a single, or a few correct answers. A question which can generate many answers at the whims of people's subjective opinion, is better left to discussion forums.
    – Cdn_Dev
    Mar 17, 2017 at 17:39
  • But, the modern philosophy are highly being tested against the facts and evidence drawn from science. By that nature I think modern philosophy (either old or new ideas) have evolved towards being more scientific in nature. eg. 1) Why did that man steal the food? may be he/she is hungry, needs to feed a his children and didn't get a job. 2) Why are poor people poor? may be they are lazy or are they deprived of opportunities in life, or they were not smart to handle the opportunities they got, etc. I think the modern philosophical thinking can be greatly shaped by scientific facts. Mar 17, 2017 at 17:41

The natural sciences have changed the conception of life by reducing the need for a higher consciousness to explain how something that is alive is different from an inanimate object. Where before, the narrative required a deity to define what it meant for a thing to be alive, now chemistry, physics and genetics play important roles in the search to identify the activity of a living thing.

With that observation, here is my own offering: An entity is alive when it has either the ability or potential ability to reverse entropy locally over some finite period of time.

“Potential”. The entity might be dormant currently, but holds the possibility of acting in the future.

“Entropy”. The tendency of all things to change from a state of order to a state of disorder. Nothing can permanently avoid this eventual progression toward chaos. Discussions of entropy often accompany descriptions of the Second Law of Thermodynamics, which states that "there is a natural tendency of any isolated system to degenerate into a more disordered state." http://www.livescience.com/50941-second-law-thermodynamics.html

“Reverse”. To cause some part of the environment either to stop the progression toward randomness or to become more ordered. Typically, “reversal” means that the entity eats some part of the environment and causes it to become part of the ordered state of the entity itself. The rest of the environment becomes less ordered, but the entity itself does not, at least temporarily.

“Locally”. Within that part of the environment that the entity can control. Typically, “locally” means the area within the entity’s skin, exoskeleton, or other outer covering. This boundary effectively distinguishes the area where entropy is decreasing (inside the entity) from where entropy is increasing (outside the entity).

  • The question has been put on hold. I will wait a day or two to see whether and how the question is edited. Mar 19, 2017 at 6:27
  • I think the question has been changed. But, if I may ask, "What question is a good question? The one that you understand or the one that has not been asked or answered before? The question has the elements to give a direction of specificity but I think there is lack of how people really skim through it before deciding if it's a garbage or something to think about. No arrogance meant, just standing up. Thanks Mar 19, 2017 at 17:54
  • Are sugar crystal alive? When I leave a honey pot on the counter, sugar crystal are formed, reducing the disorder. You seem to misunderstand what is entropy: its not about order/disorder in the way you mean. Living beings cannot break the laws of thermodynamics either...
    – Olivier
    Mar 20, 2017 at 13:17
  • Olivier. You are right about the distinction between entropy and disorder. The crystallization example is interesting. Our colleagues at Physics Stack Exchange have discussed this; see Entropy and Crystal Growth (2013). Still, my understanding is that a living thing decreases entropy for itself; the Second Law balances the books as entropy increases more rapidly in the rest of the environment. Mar 21, 2017 at 3:12

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