We have such a limited understanding of life that calling it “just” anything, at least with any degree of confidence, seems unfounded.
Our definitions are somewhat inadequate and full of edge cases and blurred lines. It doesn’t mean we should dismiss them out of hand, especially since the circumstances of life’s origin are so mistifying.
It s not mistifying that much if you look at the chemical timescale. Give me 2 bn years and see where I go. Try to imagine what that amount of time for random permutation can give in the entire space of the universe and you're bound to have a self reproducing machine popping up once.
This is a total non sequitur. The smallest organism we know of capable of independent self replication and Darwinian evolution has billions of atoms. The complexity gap from Miller-Urey style experiments to that is enormous, vastly overwhelming mere billions of years. Maybe there's some trick that evades this gap, but if so we don't know what it is, or how likely Origin of Life would be even with the trick.
Well this seems extremely specious. To presume the entire history of life must remain in existence on a heavily life-colonized world is bizarre reasoning. Any "simple self-replicator" would have long since been exterminated by it's more sophisticated next generation species, not to mention the multiple ages of radically different environmental pressures (i.e. the oxygen apocalypse) in the Earth's history.
You're essentially arguing that the absence today of simple replicating amino-acid organisms somehow implies that they must spontaneously form far far more complex systems to do so: yet the evidence says otherwise - we know for a fact and can observe the existence of purely RNA-based enzymatic systems (https://en.wikipedia.org/wiki/RNA_world) which are curiously involved in things like protein synthesis in our cells today.
You are now committing the other Origin of Life non sequitur that annoys the hell out of me: confusing the statement "the evidence does not require one to believe X" with the statement "the evidence requires on to believe not-X".
I'm not arguing that life must be rare. I'm not arguing that the smallest Darwinian replicator must have billions of atoms. I'm arguing against the PRESUMPTION that there must be a small replicator, and the inference (from that presumption) that life must be common. There is no evidence for such a small replicator (the RNA world work does not provide it). And understand that even if the smallest replicator were much smaller than this billions-of-atoms thing, it could still present a super-astronomical complexity gap.
The evidence for small replicators is that we now have large replicators. Whatever the absolute probabilities are, the relative probability of spontaneous emergence of small replicators is much, much larger than large replicators. Therefore, large replicators most likely evolved from small replicators.
Put another way: the most likely ancestor of all replicators was probably close to the smallest molecule that works.
Ah, this is the inference "we are here, therefore life must be common".
This is bogus, because it ignores Observer Selection. We are not at a randomly chosen planet in the universe (or in a larger multiverse), we are at a planet where there exists observers who could observe life exists. The more uncommon observers are, the more biased our position would be.
Ask yourself: if OoL were exponentially unlikely, requiring super-astronomical numbers of tries to get it to occur, far beyond the number of stars (or even atoms) in our visible universe, what exactly would we see that's different from what we do see? If there is no such thing, how could current evidence rule out that possibility?
I will totally agree that the mechanism by which life arose should be among the easiest routes to life. But this doesn't mean that process was likely in any absolute sense, just that it was among the least unlikely.
I'm not claiming life must be common. The strong anthropic theory explains why we can be having this conversation despite the probability of life emerging being arbitrarily low, so there's no reason to assume the probability of life must be high.
But no matter what that probability is, when there are 2 alternative pathways for a step, we should assume the more likely one. I merely claim that
inorganics -> small replicators -> large replicators
With people as insistently contrarian as you seem to be, I really wonder what alternatives, of how life came about, you are proposing?
Is it really just pure agnostic nihilism along the lines of "We know nothing!"? Or do you know of more reasonable alternative explanations, not investigated in experiments like this?
This is false (to some degree), if my memory is correct, life on earth emerged as soon as condition where favorable ~400m years after earth was formed, I am not saying it's aliens, aliens?
Another explanation for that would be that the conditions under which life could arise were only temporary: it had to arise then, or it wouldn't arise at all. For example, possibly life arose in one of a very large number of wet planetesimals that were still warm enough (due to decay of short lived isotopes like 26Al) for the water to be liquid. Or perhaps phosphides in infalling meteorites were necessary to provide some necessary form of chemical energy.
Such a fascinating point that I did not think about, it seems this is related to competing theories what world was first; RNA world vs Protein World (may be even both).
Another possibility would be that panspermia could be possible in densely packed newly forming star clusters, like the one our solar system was born in.
These clusters can be very dense (10,000 stars per cubic parsec, perhaps). With such closely spaced stars, and with residual gas around the stars, it might be much easier for material ejected from one system to be captured in another.
So, IF life arose very early in one such system, it might spread to all the others. The statistical weight of "early OoL" events would be amplified, vs. OoL events that occurred later after the cluster had spread out and dissipated. Observers would tend to derive from these prolific spreading events, just because they'd seed so many systems.
This is a nice scenario for science fiction, since it would allow thousands of life bearing systems in our galaxy (with compatible biosystems!), while evading much of the bite of the Fermi argument. In this scenario, SETI should look for stars with compositions very similar to the Sun, spread on an arc ahead/behind our system on its orbit around the center of the galaxy (the stars would have spread to about 180 degrees along this orbit since their formation).
Self-replicating machines already happened once, in many varieties. It's far from an assumption unless you want to appeal to the idea that they were intentionally created, but that really only pushes the problem further down the stack.
The philosophical name for this concept is panpsychism.
Personally, I’m a panentropist (my own creation) - I hold that the spectrum of life/consciousness varies depending on the level of entropy. So a flame has a higher level of consciousness than a piece of paper and oxygen molecules. But when you combine them they increase their level. It’s weird but it might be correct - doesn’t address issues of the hard problem of consciousness however
> The more possible states a system has, the more room for consciousness
That is one of the postulates of Integrated Information Theory, which aims to give an account of how consciousness can arise from physical substrates. (The idea seems closely related to the concept of entropy.)
That still doesn't rectify the conflict. The living being is reducing local entropy -- meaning it's less conscious than if it maximized local entropy per gp comment. Or put in real terms, lighting yourself on fire likely does not make you more alive/conscious even though it definitely increases your entropy.
If anything, it seems like the reversal of entropy would be a better description of life. To make paper and oxygen from fire would have higher consciousness than a fire itself
I didn't say it wasn't useful. My comment is in terms of physics rather than biology or chemistry. i.e. in physics, there is little difference but complexity between a rock and a human.
I don't think that many physicists would agree. There's this whole idea if entropy in physics, which is basically a valuation of information in a system, and humans would be much more complex when looking at that than a rock. There's also a lot more interesting stuff going on inside a human body than there is for a rock.
This is also, best strategy to search of extra terrestrial life, the concept of entropy for living systems deeply fascinates me, because how simple everything becomes (conceptually); life is entropy maximization systems in universe, looking at human kind it most efficient too.
What does complexity mean, exactly? How does it demark the line between living and not, is there a threshold, and what is the threshold?
There’s also a lot more interesting stuff going on inside a car, a computer, or the planet earth that is made of rocks, than there is for an individual rock. Our solar system is extremely complex, yet is not alive. So complexity doesn’t seem to mark the line between living and non-living things at all.
Saying life is “complexity” seems reductionist and almost information-free, it doesn’t really explain or even shed any useful light on the difference between living things and non-living things, since there are plenty of examples of high complexity, low-entropy inorganic objects & systems. We can synthesize complexity all day, but we don’t know how to synthesize life yet.
Since the beginning of time, things merge. Subatomic "particles" into atoms into molecules into bigger molecules, all directed by physics. Biochemistry, is just chemistry, is just physics.
That ignores emergent features, and that it's impossible for us to describe chemistry or biology only in terms of physics. Reproduction is one of the emergent features of biology.
That doesn't sound right to me[1]. Surely physics + enough detail is biology? Maybe it's not a level of detail we actually understand with contemporary science -- hence the addition of higher level abstractions like biology which are derived "top down" rather than "bottom up" (i.e., empirically) -- but "emergent systems" != "magic".
We should distinguish the field of physics, which is a human study, from the world, which it attempts to map or model on a fundamental level. We can say biology and chemistry are made up of the fundamental stuff of the world which physics seeks to understand, but that's different from saying chemistry and biology are just the science of physics. We have different domains for a reason. How that cashes out in the world itself are metaphysical questions of ontology, emergence, reductionism, mereology and Platonism/universals. Also the status of causality and laws of nature.
But then again, philosophy is also a domain of human inquiry. The world is just whatever it is, however we think it best to describe. Problem is that our different domains of descriptions and questions don't always fit easily with one another. So to say it's all just the domain of physics is to mistake one map for the territory.
From one perspective, mathematics is the study of the methods of reasoning on abstract concepts. Theorems follow from any set of axioms that do not lead to any contradiction. In physics, one is usually only interested in results relating to the current universe we live in. In that sense, mathematics can be viewed as more general.
The commenter is likely referring to complexity from simplicity, best shown in Stephen Wolfram's Rule 30. I'll be talking about this topic, and its implications, at length in an upcoming video on https://recursion.is/youtube.
That's a really profound sounding way of saying that life is complex and we don't understand it. Or are you saying that we do understand it? If so I'm sure you're in high demand right now.
