3 ms·

>Even if you have a rock that looks exactly like a human being, say one of Phidias' statues, it will decay until it looks like every other rock given enough tim

>Even if you have a rock that looks exactly like a human being, say one of Phidias' statues, it will decay until it looks like every other rock given enough time and exposure to the elements. The same is true of living things. Given enough time, anything living is reduced to a pile of oxides. Some physical processes decrease entropy locally, sometimes by incredible amounts. That's how we have the sun. What we really take from the sun is not energy, but its stored negative entropy; energy is just the medium to move it around.

marginalia_nu 3y ago
Right, but it must be granted that the moment of death is a point where this decay accelerates greatly.
- fluoridation 3y ago
  But qualifying any particular moment as "death" already implies that we've granted the thing in question the quality of being alive at some point, so it's not a useful way to distinguish living from non-living.
  - marginalia_nu 3y ago
    But that is how we talk about living things. A man is alive, has a fatal heart attack, then he is not alive. I don't think anyone would argue he was never alive, or is still alive after having gone cold. Studying this transition from life to non-life, or vice versa should be most informative in distinguishing the two states.
    - fluoridation 3y ago
      Sure, but the question is not about distinguishing living from dead things, but about distinguishing currently and formerly living things from things that were never alive. More specifically, about distinguishing them structurally, not comparatively. If "death" is the point where the decay into entropy of something greatly accelerates then hypothetically we could say a rock "dies" when it's melted, or alternatively we could say that it doesn't "die" because it was never alive. The distinction does not lie on the thing itself, but on which things we assign the property of being able to "die".
      - marginalia_nu 3y ago
        The argument has never been that this is a sufficient criterion for life, but rather that it is necessary and not merely accidental the same way you can be alive and not have legs. There does not to my knowledge exist things that are considered living that don't have this property of locally decreasing entropy.
        fluoridation 3y ago
        Fair enough. It is indeed true that living things seek to maintain their entropy low.
grive 3y ago
For the majority of life existence as we know it (meaning, a proton gradient separated by a membrane), living systems were immortal. Some external circumstances could change reducing them to a pile of oxides, but the systems themselves were perfectly self-perpetuating -- i.e. time-independent, or put another way 'given enough time' is not sufficient. Of course, before the heat-death of the universe entropy-reducing systems will break down, but that's not an interesting observation. > Some physical processes decrease entropy locally, sometimes by incredible amounts. I think that's the more interesting observation. How to qualify life beyond only 'local entropy reduction systems'. My uninformed opinion is that it is both 'entropy-reducing' and 'context-dependent' systems that should be considered 'alive' (not sure though that this is sufficient). Dependence on their context means that those systems will have a feedback-loop with their environment, allowing for example non-linear causality and thus complexity to emerge. A star radiating away their stored negative entropy is an all give and no take, no dependency, full autonomy system. Of course they can still be impacted by external effects, but sustaining their own internal processes does not require such inputs, they are incidental to them emitting away their stored energy. Once started, their schedule (when they will deplete themselves, collapse, etc) is known and predictable, thus not alive.
- fluoridation 3y ago
  > Of course, before the heat-death of the universe entropy-reducing systems will break down, but that's not an interesting observation. Excuse the snark, but it's exactly as interesting as saying that some living systems are immortal until they're no longer immortal. If a protocell or a virus stops being alive (if we grant that it's alive) when it falls into a fire then it's not immortal just because it has no metabolism. >Once started, their schedule (when they will deplete themselves, collapse, etc) is known and predictable, thus not alive. Actually, no. For example, a star could hypothetically fall into another much larger than it and prolong its life, if we were to say that it lives. The only reason it's predictable is because a star can't move on its own to hunt weaker stars, and because (at least at this time in the history of the universe) stars are far enough apart that they rarely fall into each other. If that was a common occurrence it would be much more difficult to predict how long until a star burns out.

marginalia_nu 3y ago

Right, but it must be granted that the moment of death is a point where this decay accelerates greatly.

fluoridation 3y ago
But qualifying any particular moment as "death" already implies that we've granted the thing in question the quality of being alive at some point, so it's not a useful way to distinguish living from non-living.
- marginalia_nu 3y ago
  But that is how we talk about living things. A man is alive, has a fatal heart attack, then he is not alive. I don't think anyone would argue he was never alive, or is still alive after having gone cold. Studying this transition from life to non-life, or vice versa should be most informative in distinguishing the two states.
  - fluoridation 3y ago
    Sure, but the question is not about distinguishing living from dead things, but about distinguishing currently and formerly living things from things that were never alive. More specifically, about distinguishing them structurally, not comparatively. If "death" is the point where the decay into entropy of something greatly accelerates then hypothetically we could say a rock "dies" when it's melted, or alternatively we could say that it doesn't "die" because it was never alive. The distinction does not lie on the thing itself, but on which things we assign the property of being able to "die".
    - marginalia_nu 3y ago
      The argument has never been that this is a sufficient criterion for life, but rather that it is necessary and not merely accidental the same way you can be alive and not have legs. There does not to my knowledge exist things that are considered living that don't have this property of locally decreasing entropy.
      - fluoridation 3y ago
        Fair enough. It is indeed true that living things seek to maintain their entropy low.

grive 3y ago

For the majority of life existence as we know it (meaning, a proton gradient separated by a membrane), living systems were immortal. Some external circumstances could change reducing them to a pile of oxides, but the systems themselves were perfectly self-perpetuating -- i.e. time-independent, or put another way 'given enough time' is not sufficient. Of course, before the heat-death of the universe entropy-reducing systems will break down, but that's not an interesting observation. > Some physical processes decrease entropy locally, sometimes by incredible amounts. I think that's the more interesting observation. How to qualify life beyond only 'local entropy reduction systems'. My uninformed opinion is that it is both 'entropy-reducing' and 'context-dependent' systems that should be considered 'alive' (not sure though that this is sufficient). Dependence on their context means that those systems will have a feedback-loop with their environment, allowing for example non-linear causality and thus complexity to emerge. A star radiating away their stored negative entropy is an all give and no take, no dependency, full autonomy system. Of course they can still be impacted by external effects, but sustaining their own internal processes does not require such inputs, they are incidental to them emitting away their stored energy. Once started, their schedule (when they will deplete themselves, collapse, etc) is known and predictable, thus not alive.

fluoridation 3y ago
> Of course, before the heat-death of the universe entropy-reducing systems will break down, but that's not an interesting observation. Excuse the snark, but it's exactly as interesting as saying that some living systems are immortal until they're no longer immortal. If a protocell or a virus stops being alive (if we grant that it's alive) when it falls into a fire then it's not immortal just because it has no metabolism. >Once started, their schedule (when they will deplete themselves, collapse, etc) is known and predictable, thus not alive. Actually, no. For example, a star could hypothetically fall into another much larger than it and prolong its life, if we were to say that it lives. The only reason it's predictable is because a star can't move on its own to hunt weaker stars, and because (at least at this time in the history of the universe) stars are far enough apart that they rarely fall into each other. If that was a common occurrence it would be much more difficult to predict how long until a star burns out.