1. Abiogenesis explains the origin of life
Summary:
Life arose from non-living matter, first through chemical reactions that led to organic molecules, then to molecules capable of reproducing themselves, then enzymes, then eventually to single-celled life. While the moment of going from organic molecules to life has not been empirically proven, evidence points to its possibility.
Sun Kwok & Yong Zhang, PhDs, Chinese astronomer & molecular biologist
“Researchers from Hong Kong report that organic compounds of unexpected complexity exist throughout the Universe. They indicate that an organic substance commonly found throughout the Universe contains a mixture of aromatic and aliphatic components. The results suggest that complex organic compounds are not the sole domain of life but can be made naturally by stars.”
―Sun Kwok & Yong Zhang, “Mixed aromatic–aliphatic organic nanoparticles as carriers of unidentified infrared emission features,” Nature, 479, p80, 2011
“Researchers from Hong Kong report that organic compounds of unexpected complexity exist throughout the Universe. They indicate that an organic substance commonly found throughout the Universe contains a mixture of aromatic and aliphatic components. The results suggest that complex organic compounds are not the sole domain of life but can be made naturally by stars.”
―Sun Kwok & Yong Zhang, “Mixed aromatic–aliphatic organic nanoparticles as carriers of unidentified infrared emission features,” Nature, 479, p80, 2011
Caleb Scharf, British astrophysicist
Equation: The average number of origin-of-life events for a given planet = (number of building blocks on planet) × 1/(average [mean] number of building blocks needed per “organism”) × (availability of building blocks during time t) × (probability of assembly in a given time) × time. Credit: Caleb Scharf and Lee Cronin
“If the value of Pa is very low, it’s extremely unlikely that life will form even when the ingredients are there—potentially explaining why humans haven’t yet happened to create life in the lab, even if scientists have used the right ingredients, Scharf said. But a planet-wide ‘lab’ would increase the odds that life-creating events will occur.
“We might have to wait 100 million years for it to fall into place just in a test tube,” Scharf said. ’Whereas on a planet scale, you’ve got a trillion test tubes—probably even more than that. It’s conceivable that, using this equation, playing these games, is hinting at a possible explanation for why we haven’t seen life miraculously appearing in our laboratories, that...there’s some subtle thing that has to happen that really doesn’t happen often.’”
―Caleb Scharf (quoted by Sarah Lewin Frasier), “New Equation Tallies Odds of Life Beginning,” Scientific American, July 11, 2016
2. Mathematical Evidence for the Spontaneous Origin of Life
Summary:
Various mathematical principles can explain patterns of self-organization that would make life tend to arise on its own wherever possible.
Paul Davies, PhD, English physicist & professor, 1946-
“...Imagine, for example, a checkerboard with checkers set out in some arrangement. One can then consider definite rules for how the pattern might be rearranged. Here is an example: Each square on the board has eight adjacent squares (including the diagonal neighbors). The state of any given square remains unchanged (i.e., with or without checker) if precisely two of the neighboring squares are occupied by checkers. If an occupied square has three occupied neighbors, it remains occupied. In all other cases the square becomes or remains empty. Some initial distribution of checkers is chosen, and the rule is applied to every square on the checkerboard. A slightly different pattern from the initial one is thereby obtained. The rule is then applied again, and further changes occur. The rule is then repeated and repeated, and the evolution of the pattern observed.
“The particular rules given above were invented by John Conway in 1970, and he was instantly startled by the richness of the structures that resulted. Patterns appeared and disappeared, evolved, moved about, fragmented, merged. Conway was struck by the resemblance of these patterns to living forms, so he called the game ‘Life.’ Computer buffs the world over soon became addicted to it...
“One can consider the space occupied by the dot patterns as a model universe, with Conway’s rules substituting for the laws of physics, and time advancing in discrete steps. Everything that happens in the Life universe is strictly deterministic: the pattern at each step is completely determined by the pattern at the preceding step. The initial pattern thus fixes everything to come, ad infinitum. In this respect the Life universe resembles the Newtonian clockwork universe. Indeed, the mechanistic character of such games has earned them the name ‘cellular automata,’ the cells being the squares or pixels.
“Among the infinite variety of Life forms are some that retain their identity as they move about. These include the so-called gliders, consisting of five dots, and various larger ‘spaceships.’ Collisions between these objects can produce all sorts of structures and debris, depending on the details. Gliders can be produced by a ‘glider gun,’ which emits them at regular intervals in a stream. Interestingly, glider guns can be made from thirteen-glider collisions, so that gliders beget gliders. Other common objects are ‘blocks,’ stationary squares of four dots that tend to destroy objects that collide with them. Then there are the more destructive ‘eaters,’ which break up and annihilate passing objects, and then repair the damage to themselves occasioned by the encounter. Conway and his colleagues have discovered Life patterns of immense richness and complexity, sometimes by chance, sometimes using great skill and insight...
“The Life universe is obviously only a pale shadow of reality, the lifelike nature of its simpler inhabitants constituting merely a cartoon of real living things. Yet buried within its logical structure Life has the capacity to generate unlimited complexity, in principle as complex as genuine biological organisms. Indeed, [John] von Neumann’s original interest in cellular automata was closely connected with the mystery of living organisms. He was fascinated to know whether a machine could in principle be built that is capable of reproducing itself, and if so what its structure and organization might be. If such a von Neumann machine is possible, then we would be able to understand the principles that enable biological organisms to reproduce themselves.”
— Paul Davies, The Mind of God, Touchstone, 1992 p110-112
“Self-reference and self-reproduction are closely related, and once the existence of universal Life computers had been established, the way was open for Conway to prove the existence of universal constructors and hence genuine self-reproducing Life patterns. Again, no such pattern has actually been constructed, for it would be truly vast. But Conway reasons that, in an infinite Life universe randomly populated by dots, self-reproducing patterns would inevitably form somewhere just by chance. Although the odds against the spontaneous formation of such a complex and highly orchestrated pattern are astronomical, in a truly infinite universe anything that can happen will happen. One can even envisage Darwinian evolution leading to the appearance of ever more complex self-reproducing patterns.
“Some Life enthusiasts assert that such self-reproducing Life patterns really would be alive, because they would possess all the attributes that define living organisms in our universe. If the essence of life is regarded simply as energy organized above a certain threshold of complexity, then they are right. In fact, there is now a distinct branch of science called ‘artificial life’ which is devoted to studying self-organizing, adaptive, computer-generated patterns...”
— Paul Davies, The Mind of God, Touchstone, 1992 p115
“The basis of [John] von Neumann’s analysis was the concept of a ‘universal constructor’ analogous to a universal computer. This would be a machine that could be programmed to produce anything, much as a Turing machine can be programmed to execute any computable mathematical operation. von Neumann considered what would happen if the universal constructor were programmed to make itself. Of course, to qualify for genuine self-reproduction a machine has to produce not only a copy of itself, but also a copy of the program of how to copy itself; otherwise the daughter machine will be ‘sterile.’...
“...After a lot of work, von Neumann and his colleagues were able to show that self-reproduction is indeed possible for systems that exceed a certain threshold of complexity. To do this required the investigation of a cellular automaton with rules considerably more complicated than those of [Conway’s] Life game. Rather than allowing each cell to be in only one of two states – empty or occupied – von Neumann’s automaton permitted no fewer than twenty-nine alternative states... Shortly after this mathematical investigation was completed came the flowering of molecular biology, with the discovery of the double-helix structure of DNA, the unraveling of the genetic code, and the elucidation of the basic organization of molecular replication. It was soon realized that nature employs the same logical principles discovered by von Neumann. Indeed, biologists have identified the actual molecules within living cells that correspond to the components of a von Neumann machine.”
— Paul Davies, The Mind of God, Touchstone, 1992 p112-113
“...Imagine, for example, a checkerboard with checkers set out in some arrangement. One can then consider definite rules for how the pattern might be rearranged. Here is an example: Each square on the board has eight adjacent squares (including the diagonal neighbors). The state of any given square remains unchanged (i.e., with or without checker) if precisely two of the neighboring squares are occupied by checkers. If an occupied square has three occupied neighbors, it remains occupied. In all other cases the square becomes or remains empty. Some initial distribution of checkers is chosen, and the rule is applied to every square on the checkerboard. A slightly different pattern from the initial one is thereby obtained. The rule is then applied again, and further changes occur. The rule is then repeated and repeated, and the evolution of the pattern observed.
“The particular rules given above were invented by John Conway in 1970, and he was instantly startled by the richness of the structures that resulted. Patterns appeared and disappeared, evolved, moved about, fragmented, merged. Conway was struck by the resemblance of these patterns to living forms, so he called the game ‘Life.’ Computer buffs the world over soon became addicted to it...
“One can consider the space occupied by the dot patterns as a model universe, with Conway’s rules substituting for the laws of physics, and time advancing in discrete steps. Everything that happens in the Life universe is strictly deterministic: the pattern at each step is completely determined by the pattern at the preceding step. The initial pattern thus fixes everything to come, ad infinitum. In this respect the Life universe resembles the Newtonian clockwork universe. Indeed, the mechanistic character of such games has earned them the name ‘cellular automata,’ the cells being the squares or pixels.
“Among the infinite variety of Life forms are some that retain their identity as they move about. These include the so-called gliders, consisting of five dots, and various larger ‘spaceships.’ Collisions between these objects can produce all sorts of structures and debris, depending on the details. Gliders can be produced by a ‘glider gun,’ which emits them at regular intervals in a stream. Interestingly, glider guns can be made from thirteen-glider collisions, so that gliders beget gliders. Other common objects are ‘blocks,’ stationary squares of four dots that tend to destroy objects that collide with them. Then there are the more destructive ‘eaters,’ which break up and annihilate passing objects, and then repair the damage to themselves occasioned by the encounter. Conway and his colleagues have discovered Life patterns of immense richness and complexity, sometimes by chance, sometimes using great skill and insight...
“The Life universe is obviously only a pale shadow of reality, the lifelike nature of its simpler inhabitants constituting merely a cartoon of real living things. Yet buried within its logical structure Life has the capacity to generate unlimited complexity, in principle as complex as genuine biological organisms. Indeed, [John] von Neumann’s original interest in cellular automata was closely connected with the mystery of living organisms. He was fascinated to know whether a machine could in principle be built that is capable of reproducing itself, and if so what its structure and organization might be. If such a von Neumann machine is possible, then we would be able to understand the principles that enable biological organisms to reproduce themselves.”
— Paul Davies, The Mind of God, Touchstone, 1992 p110-112
“Self-reference and self-reproduction are closely related, and once the existence of universal Life computers had been established, the way was open for Conway to prove the existence of universal constructors and hence genuine self-reproducing Life patterns. Again, no such pattern has actually been constructed, for it would be truly vast. But Conway reasons that, in an infinite Life universe randomly populated by dots, self-reproducing patterns would inevitably form somewhere just by chance. Although the odds against the spontaneous formation of such a complex and highly orchestrated pattern are astronomical, in a truly infinite universe anything that can happen will happen. One can even envisage Darwinian evolution leading to the appearance of ever more complex self-reproducing patterns.
“Some Life enthusiasts assert that such self-reproducing Life patterns really would be alive, because they would possess all the attributes that define living organisms in our universe. If the essence of life is regarded simply as energy organized above a certain threshold of complexity, then they are right. In fact, there is now a distinct branch of science called ‘artificial life’ which is devoted to studying self-organizing, adaptive, computer-generated patterns...”
— Paul Davies, The Mind of God, Touchstone, 1992 p115
“The basis of [John] von Neumann’s analysis was the concept of a ‘universal constructor’ analogous to a universal computer. This would be a machine that could be programmed to produce anything, much as a Turing machine can be programmed to execute any computable mathematical operation. von Neumann considered what would happen if the universal constructor were programmed to make itself. Of course, to qualify for genuine self-reproduction a machine has to produce not only a copy of itself, but also a copy of the program of how to copy itself; otherwise the daughter machine will be ‘sterile.’...
“...After a lot of work, von Neumann and his colleagues were able to show that self-reproduction is indeed possible for systems that exceed a certain threshold of complexity. To do this required the investigation of a cellular automaton with rules considerably more complicated than those of [Conway’s] Life game. Rather than allowing each cell to be in only one of two states – empty or occupied – von Neumann’s automaton permitted no fewer than twenty-nine alternative states... Shortly after this mathematical investigation was completed came the flowering of molecular biology, with the discovery of the double-helix structure of DNA, the unraveling of the genetic code, and the elucidation of the basic organization of molecular replication. It was soon realized that nature employs the same logical principles discovered by von Neumann. Indeed, biologists have identified the actual molecules within living cells that correspond to the components of a von Neumann machine.”
— Paul Davies, The Mind of God, Touchstone, 1992 p112-113