> A more inclusive representation is to recognize a spectrum between the non-living and the living—a “grayness” resulting from the protracted evolutionary process that gave rise to life.<p>The meaning of "grayness" would appear to have something to do with the fuzzy line between life and non-life.<p>There is a footnote to the article "The Seven Pillars of Life":<p><a href="https://www.pps.net/cms/lib/OR01913224/Centricity/Domain/3337/SevenPillarsofLife.pdf" rel="nofollow">https://www.pps.net/cms/lib/OR01913224/Centricity/Domain/333...</a><p>But it doesn't mention grayness at all.<p>This gets cleared up a little a few paragraphs in:<p>> The ability to clearly distinguish between abiotic and biotic systems is considered by many a prerequisite for effective astrobiology studies. However, since no natural demarcation truly exists, there is a profound difficulty in advancing the field if we rely on a strict dichotomy. ...
A few offshoots from this line of thinking…<p><i>Where do viruses sit on this scale of grayness?</i><p>Yes, viruses have organic molecules, information storage systems, and compartmentalization. No, viruses do not have metal catalysis (correct me if I’m wrong) nor do they have energy currencies (they rely on hosts for energy). Viruses appear rather gray indeed.<p><i>Can the grayness framework be modified/extended to describe superorganisms?</i><p>Superorganisms like bee colonies are only mentioned in passing and the authors do not try to apply their grayness framework. Organic molecules and metal catalysis aren’t as relevant beyond the molecular scale, but information storage systems, energy currencies, and compartmentalization apply just as well to superorganisms. Perhaps those are the more generalizable attributes of life.<p>I’m reminded of concepts from Schrödinger’s <i>What Is Life?</i>. Schrödinger describes local reduction of entropy to be a key feature — combining energy currencies with compartmentalization is one way to achieve that. Separately, he discusses the hereditary mechanism and suggests an “aperiodic crystal” could encode heritable information.<p><i>What would be the contents of a sister article titled “The Grayness of the Origin of Consciousness”?</i><p>I would love to see an outline.
So interesting! Some similar work on this area:<p><a href="https://www.nature.com/articles/s41467-021-23258-x" rel="nofollow">https://www.nature.com/articles/s41467-021-23258-x</a><p><a href="https://ui.adsabs.harvard.edu/abs/2020AGUFMP001...01C/abstract" rel="nofollow">https://ui.adsabs.harvard.edu/abs/2020AGUFMP001...01C/abstra...</a>
I find it fascinating that abiotic chemical/physical cycles are considered an integral part of early life (e.g. if your nutrient transport is environmental osmosis/tides/whatever, you're still alive but the larger environment is an integral part of your biochemistry).<p>From that perspective the freshwater cycle is still a major component of biochemistry (bulk ion transport) on Earth, despite arguably being a physical state change and not chemistry per se.<p>The Sun provides photons that most cells need in order to live but Desulforudis audaxviator have decoupled themselves from that source of energy. In theory they could outlast the solar system or hitch a ride on a rogue planet.
I'm personally convinced at this point that most everyday distinctions between living and dead are arbitrary human categorizations. Even a "dead body" is teaming with life. As far as "inanimate matter" is concerned, all matter is ultimately part of a plethora of various different cycles and processes of transformation and recapitulation... even if something temporarily looks like it's static to us and our meager little narrow timeframe of experience, it's not.<p>Just to clarify, I don't mean that these distinctions are meaningless, just that their meaning is inherently embedded in human experience.
A nice article. It seems likely that we will never really know how life started.<p>It is still very interesting to research this subject, because it might help us to learn more about the possibility of life on other planets.
There is also grayness in the question "what is an individual organism?"<p>For example, you can look at a single bacterium as an organism. But you can also look at a colony of bacteria as an organism.