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Maybe you should expand your definition of life to not require proteins. From Wikipedia: > From a physics perspective, living beings are thermodynamic systems
by 21 9y ago
Maybe you should expand your definition of life to not require proteins.
From Wikipedia:
> From a physics perspective, living beings are thermodynamic systems with an organized molecular structure that can reproduce itself and evolve as survival dictates. ... A major strength of this definition is that it distinguishes life by the evolutionary process rather than its chemical composition.
- alextheparrot 9y agoIs a sterile human not alive by this definition? I find that life needing to reproduce is a questionable condition. If we say reproduction is not requisite, then neither is evolution as evolution requires generations. "Evolve as survival dictates" is a bit pointless, as if you don't change to survive (Assuming the change is requisite) you do not survive. Survival is defined as still being alive, so if you don't survive you are no longer alive and thus not living. We've then defined a state where a living being must continue living to be living, well sure - I agree.
- 21 9y agoIf you remove reproduction, remove evolution, what else is left? Evolution doesn't necessarily involve reproduction. A sufficiently advanced human (or computer) could enhance itself technologically, continuously replace it's organs (Ghost in the Shell), even change it's form and this would count in my book as a form of (non-biological) evolution. You could say the same thing about culture. I think that definition is more for lower level life forms, where is not clear (see viruses). Higher forms of life could be defined differently - agency, ability to sustain/repair itself, opposition towards environment. But then you might encounter difficulties with classifying a self repairing (non-sentient) robot as "alive".
- Koshkin 9y ago> Evolution doesn't necessarily involve reproduction. According to Darwin, it does. A giraffe got its long neck not by stretching it but by dying if the neck was not long enough to survive and letting the ones with (accidentally) better genes to live on and - importantly - reproduce.
- alextheparrot 9y agoMy apologies, I was being a bit pedantic - Evolution is formally traits changing over generations, while adaption is changing traits over an organism's lifetime, though I believe you are using them interchangeably as "something changing". I don't know what is left, but I have a hard time using such an embattled definition.
- Koshkin 9y agoWell, your sterile human appears to be a strawman. Obviously, a person may be sterile, but the organism cannot stay alive if the continual process of reproduction (of cells, their organelles, and molecules) inside it ever stops. A multi-cell organism is an emergent phenomenon that helps protein-based molecular structures to do their thing ("life").
- alextheparrot 9y agoNo, it isn't. Imagine a hypothetical sterile human that was single celled - suddenly we've reached the same conclusion without the sub-organism reproduction issue. Making reproduction a core premise of being alive really drives to the idea of mortality, as reproduction is a way of overcoming our mortal coils. Yet, it is truly reasonable to classify reproduction as the only way? It also assumes a lineage, which is not required for synthetically created organisms. I've said this elsewhere, but proteins are not required, in any regard, for life. They are an emergent phenomenon of the Earth's chemistry, not a rule for life. I mean, what is a cell even - "A fluid filled, membrane enclosed thing"? The reason cells are structured as they are is because of water, so a non-water based organisms would likely look much, much different.
- Koshkin 9y agoSomehow I am having hard time imagining a single-celled, synthetically created, non-water-based, sterile human being... I am not sure I understand the drive to redefine life beyond the life as we know it (i.e. what it actually is, as a fact), the drive that leaves one in what can only be seen as the domain of fiction at best (and pseudo-science at worst).
- Koshkin 9y agoThere are a few things that are wrong with Wikipedia's (re)definition of life; one thing I would like to mention is that what is missing from it is that a "living being" cannot exist outside of a pretty rich (and sufficiently dense) material environment, which 'space' as such is not. Incidentally, a galaxy-size dense environment (and the creature itself) would collapse into a bunch of stars and black holes "in no time".
- seszett 9y ago> a "living being" cannot exist outside of a pretty rich (and sufficiently dense) material environment What makes you say that, though? I don't see any reason for it. Some ethereal galaxy-scale lifeform might be thinking as well that "life cannot exist in the extremely hot, hyperdense environment of a planet" for example. This is pure speculation from your part.
- Koshkin 9y agoYou may be right about ethereal lifeforms, but real ones need to eat, breathe, etc.; they are also subject to the laws of thermodynamics: they need energy, and also in order to maintain low entropy inside they must increase the entropy of the environment - which would be hard if there was no environment to speak of.