The Origin of Life has become the focus of those who want a scientific argument for the existence of an Intelligent Designer – God or some other substitute – and the argument linking the Origin with God is more or less the same. Spontaneous assembly is the usual strawman target of the argument – that a living cell formed de novo out of precursor chemicals in one giant leap. This Design Argument has a long pedigree, as it features in Plato’s “Timaeus”, Cicero’s “On the Nature of the Gods” and various early Christian writings. The formation of a living cell is likened to the assembly of a complex machine, like an old-style mechanical pocket watch or a Jumbo Jet. The process of chemical assembly is then likened to a tornado or some other energetic event sweeping in and then departing, leaving a working cell behind. Like all strawman arguments, this makes the proposition (spontaneous assembly) seem absurd, and leaves the inference of a Designer for the reader to come to.
Of course, as many people have pointed out, the Designer requires some explanation since they’re presumably even more complex than the Life they’ve produced “from nothing” (ex nihilo). No process of origin is proposed for the Designer, thus the offered ‘explanation’ – that Life was made – isn’t really an explanation. Merely a dogma to be believed. While that suits belief, it doesn’t really make for a scientific explanation.
Thus the Puzzle remains unsolved – Life came from non-Life. Within the Universe’s causal horizon there’s some ~10^80 atoms, with time enough since the Big Bang to have performed ~10^122 computations, if the Universe were a vast singular Computer. Imagine a long chain molecule, composed of similar subunits. Each sub-unit is bonded to its neighbour by a covalent bond, and can flex around into 10 different possible positions. Imagine computing all the possible configurations of given strings of sub-units. Each sub-unit can be in 10 positions thus the possible combinations are 10 x 10 x 10 x 10… a ten-fold increase for each additional sub-unit. Our entire Universe, operating as a computer, could only explore all the configurations for a string merely 122 sub units long.
Origin of Life researcher Eugene Koonin, in a sub-section of his tome “The Logic of Chance”, focuses on the mystery of the transcription process – DNA to RNA to amino acids to proteins. He then describes a minimal RNA-based organism with a simplified transcription system, much simpler than the simplest known bacterium or archeon, and computes the improbability of its spontaneous formation to be 10^(1018) to 1 against. The exact figure is vastly beyond the random computing capabilities of our causally connected Universe. Koonin thus invokes the vastly greater resources of the Inflationary Multiverse – something most biologists only vaguely know about and might confuse with the Everettian Multiverse of Quantum Mechanics. The two are distinct. The Inflationary Multiverse is a product of so-called Eternal Inflation, which is the random creation of sub-Universes (like our own) out of a much bigger universe-creating inflaton field. In a sense, this is about as close to theology as modern Cosmology gets, but aspects of the theory can be tested scientifically, rather than merely known by faith.
Is it really necessary to make Life an event that is so utterly improbable and the resulting Observers a feature of an immensely tiny fraction of all possible worlds? On this basis more than one atheist (eg. philosopher Anthony Flew) has looked to an Eternal Being – a Creator – as an answer. But that’s merely pushing a Mystery into the infinite past. An Eternal Being always IS, has no Origin, yet to invoke it as an explanation seems like explanatory over-kill. Not unlike the eternal Inflaton field.
Yet the origin of Life’s complexity seems like it should have an answer, since the simplest living things quite adeptly turn non-living chemicals directly into living matter.
There are other natural processes that occur all the time in every living thing which, until we looked closely, seemingly exhaust the computational capacity of the Universe too, yet most commentators would be reluctant to invoke the need for a Designer. Protein folding is one such process. Proteins are, as I described more generally above, molecular chains composed of sub-units – in the case of living things a particular set of amino acids – that can exist in several possible positions.
In the late 1960s Guy Levinthal first posed the puzzle – how do proteins fold so quickly, if there’s so many possible positions? A 100 amino-acid long protein string would need to explore ~10^100 possible positions, yet such proteins find their ‘correct’ form within seconds to minutes. No Eternal Guiding Hand seems to be involved in the process, which occurs millions of times per second in every living body.
Of course, proteins don’t always fold into one position every time – there are such things as ‘prions’, which are transmissible alternative configurations for a given protein that can be disease causing, but can also allow a given amino-acid sequence to perform multiple functions. Yet even prions fold into their alternative form without ‘getting lost’ on the way.
The problem has been attacked and solved from two different directions. On the one hand, the configurations, thanks to the force-field nature of covalent bonds, can be described as minima in an energy potential ‘landscape’. The final form of the folding protein is thus the point of lowest energy and so it naturally ‘rolls downhill’ into that form. This description has been verified by computations of the fields themselves from basic molecular physics, which simplifies the business of finding and exploring new kinds of proteins, without the need for laborious chemical experiments in the laboratory.
On the other hand, the possible configurations themselves have physical constraints – for example, possible configurations that cause the chain to pass-through itself obviously can’t exist. Thus the number of possible configurations that a folding protein must oscillate through to find its minima as it is ‘rolling down’ the energy hill are constrained to be far fewer than a naive ‘all possible configurations’ calculation implies. As one researcher puts it, instead of ~10^(2N) possible forms (N being the number of amino acids in the string), there’s something more like 10^(N/15) possible forms. At least for short proteins. This is also borne out by experimental data.
In light of protein-folding, my intuition is that ‘random chemicals reacting randomly’ to make a living cell is an utterly inadequate straw-man parody. Those chemicals take up a vast variety of forms via spontaneous self-organisation, yet not “all possible forms”, and then that sub-set of possible forms themselves then build up into higher levels of complexity that simultaneously constrains the configuration space that must then be explored by biomolecules that are ‘feeling their way’ towards life. I say that way advisedly, because no biomolecule is an inert chunk like a LEGO piece, to be fitted into a structure. They’re composed of molecules held together via forces fields, constantly agitated and oscillating and attracting and repelling other molecules around them.
How else do the molecular pieces of quasi-organisms like viruses put themselves together inside living cells? How else do proteins fold themselves after their amino acids are strung together? How else do self-replicating ribozymes copy themselves inside a laboratory test-tube? What matter *isn’t* is ‘lifeless’, ‘mindless’ or ‘merely random’.
Even Eugene Koonin, who knows better than most, hasn’t written off the possibility of an elegant molecular pathway from random ribozymes to a living transcription system being found by our combined laboratory and theoretical fumblings. He mentions ‘Eternal Inflation’ as a naturalistic default option – a challenge for Origin of Life researchers to try harder than merely invoking brute force random origins or ineffable Eternal Beings.