Can anyone please help with definition of living and non-living. what is that dividing line that divides livings from non-livings.

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    What kind of answer are you expecting to hear? As you ask here, I guess it's not something like "they have living processes like..." So, how about "They have a telos"? Would that be an answer? Maybe your question is, as it stand, too broad and unclear. – iphigenie Jan 14 '15 at 22:22
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    This question appears to be off-topic because it is about the meaning of a word used in biological sciences. – Rex Kerr Jan 14 '15 at 23:20
  • This question is the basis of a body of philosophical literature in philosophy of biology. – ChristopherE Jan 15 '15 at 1:27
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    I disagree - analytical philosophy has a lot to say about it. – iphigenie Jan 15 '15 at 1:27
  • i remember being taught this is like year 2 of primary school lol, they gave us seven qualities to remember :) – user6917 Jan 15 '15 at 2:26

The answer is that there is no dividing line.

The definition of living vs. non-living is one which is very important to us, and yet nobody has a fully agreed upon line in the sand. Even science, which has entire categorizations for living things, openly admits that all it has is a list of things living things tend to have; it lacks a checklist you can do to test whether something is alive or not.

This is actually a big deal on the edge case: death. Because science doesn't have a solid definition of life, it also does not have a solid definition of death. There are cases we all agree upon (a putrefying corpse is dead), but there are cases we aren't certain about (heartbeat but no brain function, or brain function with no heartbeat).

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  • This is not entirely accurate. For example, in The Principles of Life, Tibor Ganti does lay out a coherent list of criteria for living, dead, and non-living systems. I am not a biologist, so I can't comment on how well accepted those ideas are in the biology community. – BKE Feb 21 '18 at 22:54
  • @BKE It would be interesting to see what those criteria are. I do know that I have seen many lists, and each of them has quirks. Given a particular list, I could look into the fuzzy boundaries or undesirable categorizations, but I'd need to see what the list is. I also know the question of "is this body alive" is a tremendously important question for doctors when dealing with patients that are in a coma. If the dividing line was clear, I think there's a lot of doctors that would greatly appreciate being notified. – Cort Ammon Feb 21 '18 at 23:01
  • mitpressjournals.org/doi/abs/10.1162/… Ganti characterises a unit of life as a unit with metabolism, stability, and control. Units also form hierarchies which can be in different states in different levels. Ganti was particularly interested in minimal life, the minimal possible unit that can be called living. I would also like to point out that your criteria of practical applicability in medicine is not a fair one. Valid and valuable theoretical groundwork can be laid, without providing all answers in practice. – BKE Feb 21 '18 at 23:31
  • @BKE True. If one is willing to accept an inconsistent, incomplete, or inaccurate definition, then definitions are easy to acquire. – Cort Ammon Feb 21 '18 at 23:33
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    @BKE Such a review could be an interesting artifact. You might be able to phrase a question which won't get closed that could capture that list. I know of at least a half dozen off the top of my head. I bet it could get to 2 dozen with proper research. – Cort Ammon Feb 22 '18 at 0:20

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