From Digg:
Will we recognize alien life when we see it?
However, one of his most interesting works is a slim book from 1944, based on a set of lectures Schrödinger gave in Dublin. It poses a single question: What is life?
Good question. As it happens, we noted earlier,
The definition of life has reached the point where science historian George Dyson tells us, “Life is whatever you define it to be.” Richard Dawkins has suggested it is “anything highly statistically improbable, but in a particular direction.” And at a year 2000 international “What is life?” conference, no two definitions were the same. Biochemist Edward Trifonov noted that there are 123 definitions available and, undeterred, promptly proposed his own: Life is self-reproduction with variations. Which was just as promptly contested. In a 2012 issue of philosophy journal Synthèse, Edouard Machery concluded that “scientists, philosophers, and ethicists should discard the project of defining life.” More.
Back to Digg:
The book is significant for predicting some important properties of DNA before they were discovered. Nearly a decade before the famous double-helix structure of DNA was uncovered, Schrödinger correctly recognized the key to how organisms evolve and pass information between generations as an “aperiodic crystal”: a chain of atoms that never precisely repeats itself. Even though each link in the chain contains the same atoms (carbon, nitrogen, oxygen, hydrogen and phosphorus), their combination allows an enormous amount of information to be encoded.
…
The hardest part of finding life elsewhere in the cosmos may be recognizing it when we see it. … Paradoxical as it may sound, there might be inorganic life, too: “organic” doesn’t mean “living.” The silicon-based life that inhabits the popular sci-fi universes of Star Trek and Terry Pratchett’s Discworld is the result of that kind of thinking. Silicon sits in the same column on the periodic table as carbon, so it is chemically similar. Ultimately the bonds it makes aren’t quite right, so we don’t see it forming the same kinds of molecules.
We see these life forms at the films all the time, produced by carbon-based life forms.
One researcher makes the case for threose, a sugar, as a precursor for RNA and DNA, but the problem is, as we also noted earlier ,
TNA has also not been found in life forms today, which is why the media release reads “ if TNA truly existed as a transitional molecule capable of sharing information with more familiar nucleic acids that would eventually come to dominate life …”
Why is the clincher evidence always disappearing, replaced by clouds of Darwinsmoke such as waft through the Digg piece? As in: You be the judge.
All life on Earth is related, with a common ancestor deep in the geologic past. But perhaps life as we know it once coexisted with other biochemistries. If that’s true, over time our distant ancestors were more successful than organisms based on alternative molecular structures, using and shaping the environment until the other forms of life became extinct. That thought is sobering: the death not of a species, but of an entire avenue that might have grown to dominate the planet if history had taken another path.More.
So, after all this commendably fine writing from Digg, where are we?
First, we don’t know that all life on Earth is related, and respected scientists such as Carl Woese, discoverer of the Archaea, doubted that, as does Craig Venter.
We know of no alternative biochemistries at the level proposed either. If the theory is that current biochemistries drove them to extinction, via Darwinian evolution, it must be labelled a speculation. The proposed threose “TNA world” may have been utterly extinguished. Alternatively, it may never have existed.
And Data is on the set filming just now.
More generally, there is also a fundamental problem with using Darwinism and common ancestry to buttress origin of life claims today :
Darwinism (natural selection acting on random mutation generates huge levels of information, not noise): The more we learn about the history of life on earth, the less evolution is theory and the more it is history. It is less like Epicureanism and more like World War II. That cannot be good for Darwinian thinking, which fills in large gaps in history by the exercise of theory. Things that “must have” happened if the theory is correct are assumed to have happened.
But history is not like that. Consider, for example, Pearl Harbor, when the Japanese crippled the U.S. Pacific fleet in a surprise attack, though the United States was not at war with Japan. Assume that the account broke off there. Maybe a theory can fill in the blanks for us and tell us what “had to” happen.
But then, what if we later discover more and more evidence for what actually happened? It will be bad news Tuesday for some theories developed in the absence of evidence — maybe for quite a few theories.
That’s a key reason that the hegemony of Darwin is weakening. So much that we now know either doesn’t fit the theory or could get on just fine without it. More.
Common ancestry was at one time mainly a religious dispute. Everyone thinks they know what happened at the iconic Scopes “Monkey” Trial (they don’t, actually).
But now, since genome mapping became routine, the unthinkable has happened: Actual genomes do not demonstrate the Tree of Life in the neat and orderly way that underlies Darwinian accounts of evolution. They could hardly be expected to do so, given the creativity many life forms exhibit with their own genes via natural genetic engineering, horizontal gene transfer, epigenetics, and a crowd of other mechanisms. The Tree of Life has become a bush or a circle of life. More.
It’s a real question now whether Darwinism and common ancestry are just padding, claiming to fill in stuff we don’t really know, to which they may be irrelevant.
But will that be admitted? Not till a lot of Darwin tenure bores retire.
See also: What we know and don’t, about the origin of life
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