The Mystery of Life Complexities
— How an investigation of life complexities intersects with Aristotelian concept of First Cause and Immaterial Soul—
When I was a child, my beloved cat came back home with his naked skin exposed in one side of his body. An angry heartless person poured a hot water onto him until he lost some of his beautiful black and white fur. I was devastated. Seeing his naked skin was so disturbing. It was like seeing a beautiful painting with a crack in the middle.
After a few days, with some medication, my cat was getting better. I noticed that small furs started to grow on the pinkish skin. Since then, I routinely checked his condition until one day, the furs finally covered all the scars. His recovery excited me! But what was more exciting was his coat pattern had come back. The new furs painted the same lines, dots, and colors in precise location that my cat had before. It was such an amazing thing to see. Who gave orders to all the cells inside my cat?
Scientists today would say that who painted back the furs of my poor cat were his genes that are responsible for fur-making. DNA encodes instructions for fur making, a specific code for specific colors and location coordinates. The RNA messenger would then go to the ribosome in cell, a place where tRNA to translate it into sequence of amino acids, which would then build the fur materials. This seems like a satisfying answer. But why is it the way it is? How did the genetic code originate? When and how did life materials emerge?
Origins Science
The field of origins science — an interdisciplinary field that investigates the origins of life — uses materialistic approach to answer this. Based on the very foundation of science, — that all atoms and molecules in a living system behave under the natural laws, — the field is crafting a new narrative on the nature of living things and its origins. In the molecular world, a strand of amino acids fold because its chemical features. Just like the phospholipid cell membranes that behave in a way that the hydrophobic part folded inside and the hydrophilic outside, allowing ions and molecules to come and go. Polymerization also occurs because there is a source of energy, an electron bouncing from a metabolism nearby, allowing monomers to chain up and fold.
A famous experiment by Stanley Miller and Urey shows that more than 25 amino acids could be produced in a condition that is similar with early earth condition. But they are not all used in living cells. Histidine, arginine, and lysine, are thought to be produced specifically in a living cell (biotic) . [13]Departing from NASA’s life definition, scientists also experimented on RNA to test its origin and reproducibility. A number of studies showed that a pair of RNA strands could act either as catalyst and information system, a crucial point to start the Darwinian evolution.[14] No need for a soul, let alone the First Cause.
But prebiotic and biochemistry are only parts of the story. Other disciplines, such as astrophysics, evolutionary biology, and geology, are also working to put the missing puzzles of life origins in scientific narrative. Too often, there are disagreements between the field. For example, astrophysicists’ model of star evolution shows that our Sun luminosity wasn’t enough to support life to flourish in the Archaean era (3.5 billion years ago), [15]but geologists found the existence of liquid water and methanogenic archaean in that era. [16]
In the cellular level, things get complicated. For a single cell to exist, a set of complex system need to be in place: RNA, enzymes, membranes, metabolism, and the genetic code. Scientists are still debating which one comes first and how each of them co-evolved and merged. As for the origin of genetic code alone, Russian-American biologist Eugene Koonin, says it is “a universal enigma” as “[it] was asked 50 years ago at the dawn of molecular biology, and might remain pertinent in another 50 years,”[17]
It seems that we need to be patient to hear the complete story or maybe we will never will?
The Improbable Life and its Causality
Statistics also plays a crucial role in scrutinizing the philosophy of life origins. [18][19]“Prebiotic chemical space is sparse,” says Greg Fournier at MIT. There were countless chemical reactions happening in early earth conditions where free metals like Fe2+, Mg2+, with the energy from lightning and UV light, could react with available molecules like H2S, H20, and HCN. But somehow life selects certain molecules that can be found on life as we know it today. Out of more than 100 amino acids available in the universe, life selects 20 “fine-tuned” amino acids. These are those whose chemical properties allow protein-folding to happen, a crucial feature of living system.
As for the self-replicating RNA to happen, according to Bernhardt (2012), it needs 100,000,000,000,000–1000,000,000,000,000 RNA molecules as a starting point to isolate one that could replicate 95-nucleotide long RNA (although some experiments show much shorter RNA could have catalysis feature too)[20]. In 2020, Tomonori Totani, at the University of Tokyo, says “the formation of such a long polymer having a correct nucleotide sequence by random reactions seems statistically unlikely,”. [21]But he then links this unlikelihood to the sparseness of an inflationary universe that includes more than 10100 stars.
“If life can emerge at least once in such a large volume, it is not in contradiction with our observations of life on Earth, even if the expected number of abiogenesis events is negligibly small within the observable universe that contains only 1022 stars,” says Totani.
While it demonstrates life’s improbability, Fournier thinks this logic is a “watchmaker” fallacy. “The probability of this molecule arising by chance is extremely low, but the probability of smaller molecules that are its constituents arising based on selection schemas may be much higher,” he says. Prebiotic chemistry and molecular biology works in a series of causality.
Robert Hazen, a mineralogist at Carnegie Institute of Sciences who works on Origins science for decades, suggest the billions of years of chemical processes to achieve life was not random, instead there is a selection for certain functions that make certain chemicals persist in creating life as we know it. Lee cronin, a chemist from University of Glasgow, offer similar reasoning called the “Assembly Theory,” a theory that states a living molecules has its own “history” of its origin. In biology, there is also a concept of path-dependence, where certain life features (such as the selection of amino acids and the origins of genetic code) happened not because of random chance, but rather, it is constrained with previous chemical reactions.
Current bottom-up lab experiments in the origins of life seems to see the origins of life as a stochastic event. This is reasonable given this is the only way we could do to verify our hypothesis. But this only provide a piece of a possible missing puzzle. For example, an experiment that shows glycolysis (a metabolic pathway that breakdown sugar) could happen in a condition similar to prebiotic ocean. It shows this mechanism was possible but that doesn’t mean it precedes the origins of another life features.
Then, if all the chemical processes involved in the origins of life was constrained with previous chemical reactions, does it mean that certain life development milestone is a necessary condition caused by previous actions? Is the chain of cause and effect the main feature of life origins? And does this chain imply an intention or purpose?
Marcelo Gleiser, a physicist at Dartmouth College, says, “Like the origins of the universe, the origins of life also suffers from First Cause problem, given that at this point, we don’t know how to frame the enigmatic passage from non-life to life in causal term,”.
Gleiser refers to Aristotle’s philosophy of biology. The Greek philosopher argued there is something immaterial behind all the matters that construct an organism. He called it vegetative soul for plants, sensitive soul for animals, and the rational soul for human beings. All these souls are immaterial as it cannot be divided and extended, and its existence is independent of the matters constructing the living thing itself. In his book De Anima, Aristotle stated, “It is a fact of observation that plants and certain insects go on living when divided into segments; this means that each of the segments has a soul in it identical in species,”
Aristotle would think that my cat’s soul was in charge for its amazing fur recovery. And that soul is emanated from the First Cause, the very beginning of the chain of causality in the entire universe. It seems like a comfortable answer for me, and for anyone growing up with religious background.
Aristotle’s concept of soul is close to the idea of soul offered by religions and belief systems today. This is not surprising because history documents its close connection with the development of philosophical thoughts within the world’s major religions. In the medieval time, Aristotelian philosophy was adopted by a group of Islamic philosophers who synthesized the ideas with Islamic philosophical and theological discourses (falsafa). Al Farabi (950 AD) used Aristotle’s idea of First Cause as the basis of his work on ethics and politics, “The Perfect City”. Thomas Aquinas in the Chatolic Church (1225), adopted the Aristotelian-Islamic philosophers’ interaction to compose his book on Christian theology, Summa Theologica.
Given this open-ended discussion of First Cause problem in science, does it mean there is still room to believe in an immaterial soul emanated from it? An immaterial thing or a vital force that animates every living thing, or in the whole life processes since the age of prebiotic-chemistry — RNA — single cell — complex multicellular — intelligent life that we know today?.
It’s a debatable question that stays for millennia across human history. Avicenna, the famous Muslim philosophers that laid foundation on modern medicines, argues there should be a Necessary Being who was the prime cause of the very long (or even infinite) chain of cause and effect. [4]But yet, some scientists are uncomfortable to talk about this. “I am interested in the origins of life, but I steer cleared of talking about science and religion,” John Sutherland, a chemist from Cambridge University, told me.
At least, I think scientists would agree on an independent idea coming from both sides of the debate: the uniqueness of life on earth that we have to preserve. Back to my cat, his coat pattern shows that he was precious. Whether one believing in his immaterial soul or holding materialistic view of life, one must have a moral obligation of protecting it. As Andrew Knoll, a geobiologist at Harvard says, “we might disagree of our past, but I think we could agree on how we build our future,”
[1] “The Internet Classics Archive | On the Soul by Aristotle.”
[2] Gildea, “On the Immateriality of the Rational Soul.”
[3] “The Internet Classics Archive | On the Soul by Aristotle.”
[4] Reisman, “Al-Fāarābī and the Philosophical Curriculum.”
[5] Douglas Giles, “Thomas Aquinas and the Great Synthesis.”
[6] “Katherine Marshall. Frogs in the History of Science. Blogspawn | Royal Society.”
[7] Coulter, Snider, and Neil, “Vitalism–A Worldview Revisited.”
[8] Masi, “Vitalism and Cognition in a Conscious Universe.”
[9] Benner, “Defining Life.”
[10] Cleland, “Life Without Definitions.”
[11] Machery, “Why I Stopped Worrying about the Definition of Life… and Why You Should as Well.”
[12] Benner, “Defining Life.”
[13] Raggi, Bada, and Lazcano, “On the Lack of Evolutionary Continuity between Prebiotic Peptides and Extant Enzymes.”
[14] Joyce, “Evolution in an RNA World.”
[15] Feulner, “The Faint Young Sun Problem.”
[16] Ueno et al., “Evidence from Fluid Inclusions for Microbial Methanogenesis in the Early Archaean Era.”
[17] Koonin and Novozhilov, “Origin and Evolution of the Genetic Code.”
[18] Kipping, “An Objective Bayesian Analysis of Life’s Early Start and Our Late Arrival.”
[19] Spiegel and Turner, “Bayesian Analysis of the Astrobiological Implications of Life’s Early Emergence on Earth.”
[20] Bernhardt, “The RNA World Hypothesis.”
[21] Totani, “Emergence of Life in an Inflationary Universe.”
[22] Wong et al., “On the Roles of Function and Selection in Evolving Systems.”
[23] Sharma et al., “Assembly Theory Explains and Quantifies Selection and Evolution.”
[24] Keller, Turchyn, and Ralser, “Non-Enzymatic Glycolysis and Pentose Phosphate Pathway-like Reactions in a Plausible Archean Ocean.”
[25] “Davidson, H. ‘Proofs For Eternity Creation and Existence of God’, 1987 PDF | PDF.”