Observable Chemistry Does Not Logically Apply to the Origin of Life

Origin-of-life researchers assume that intelligently-designed experiments in the lab can inform them about the emergence of life without design – in short, that design proves non-design.

Life uses chemistry; that’s not controversial.  What’s at issue is whether abiotic reactions on a primitive earth led to life without design.  Observing chemistry in the lab cannot speak to that question logically.  Astrobiologists assume that experiments they design for small portions of their story can be strung together into “scenarios” about life’s origin without design.  It doesn’t follow.  No one stage logically leads to another.  If each step is improbable, the improbabilities grow with each added step, becoming vanishingly small quickly.  Maintaining the story requires ample insertion of imagination —the very thing the scientific method was intended to overcome.  (Anyone can imagine that a scenario “could” happen.  Science seeks demonstrable proof.)

Moreoever, astrobiologists never entertain serious criticisms from those outside their field; i.e., from experts who do not believe life could have emerged naturally.  All their squabbles are internal.  It creates a self-reinforcing belief in naturalism, with disagreement only in the details.  Naturalism itself becomes immune to falsification. In addition, astrobiology literature is rife with oversimplification and extrapolation, seasoned with hedging words about what “could” happen or “might” happen.  A few recent examples showcase these logical fallacies.

Kick-starting life:  The leading controversy in origin-of-life theories these days concerns whether metabolism came first or genetics came first (see the two falsify each other in our 1/26/08 entry).  The metabolism-first view of Michael Russell at JPL is getting good press these days (see 12/03/04 and 2/15/08).  He claims that chemical reactions at hydrothermal vents started chain reactions that life later co-opted for metabolism.  Using a kick-starting metaphor, Astrobiology Magazine claims that “Three new papers strengthen the case the life on Earth first began at alkaline hydrothermal vents at the bottom of the oceans.”  Russell co-authored all three of these papers, so it’s no wonder they strengthen the case for his belief.  He claims his theory is testable, but the only thing he is testing is his intelligently-designed apparatus.  The observable present-day chemistry of vents, or the formation of acetate, does not logically concern the origin of life.  Imagination replaces demonstration with the use of the “could” word:

Once this early chemical pathway was forged, acetate could become the basis of other biological molecules. They also describe how two kinds of “nano-engines” that create organic carbon and polymers — energy currency of the first cells — could have been assembled from inorganic minerals.

The question is, who is the kicker?  In evolutionary theory, there is no mind or goal.  If acetate formed at a hydrothermal vent, nobody was guiding it toward bigger and better things.

Giving vent to imagination:  In a PNAS commentary, Rogier Braakman of the Santa Fe Institute attempted to support the metabolism-first scenarios at hydrothermal, again with ample use of the “could” word:

• In particular, much remains unknown about what forms of prebiotic organic chemistry could have been possible at vents, and whether they could have produced abundant biological precursors.
• Several authors have argued (5–8 [including Russell]) that on the early Earth, this would have created a global network of geochemical reactors that could have seeded life by generating and trapping organic substrates from simple inorganic inputs.
• While providing an attractive conceptual framework, the strength of such arguments will ultimately depend on experiments that confirm that prebiotic chemistry at hydrothermal vents could have indeed produced analogs of pathways seen in modern metabolism.
• Studies of this sort can thus help improve our understanding of the variability of prebiotic chemistry within and across hydrothermal vents while also making it possible to consider how the parallel activation of different (sub)networks at different vent locations could have allowed access to pathways not possible under single environmental conditions.
• Mass concentration within abiotic networks was likely important, because if matter was distributed over too many different pathways it could have significantly decreased the likelihood of more complex structures and functions emerging.
• Thus, even if total abundances of such organic inputs were high, scenarios depending on them require plausible mechanisms to explain how only small subsets of compounds could have been selected out of highly distributed sets to become part of living systems.
• If instead metabolism emerged directly from geochemical networks with inorganic inputs, and studies indicate that the number of significantly contributing pathways at hydrothermal vents was likely somewhat limited, then the sparseness of metabolism could in part be a reflection of the sparseness of hydrothermal geochemistry.

Before he died in 2007, Leslie Orgel (veteran origin-of-life researcher with Stanley Miller of spark-discharge fame) gave at least 15 reasons why metabolism-first scenarios will not work (1/26/08).  None of them were addressed in this new article.  The prior year, James Shapiro gave equally potent reasons why genetics-first scenarios will not work (2/15/07).

Flowery rhetoric is not enough:  PhysOrg gave ample space to another believer in metabolism-first scenarios, Elbert Branscomb from the University of Illinois, an admirer of Russell’s vent hypothesis.  “Cracking how life arose on Earth may help clarify where else it might exist,” the headline reads, using three hedging words in one sentence.  The grinning face of Branscomb, and his colorful prose (“The answer should help us discover what is truly necessary to spark the fateful transition from the lifeless to the living, and thereby, under what conditions and with what likelihood it might happen elsewhere”) cannot compensate for his illogic.  In a single bound, Branscome leaps from the thermodynamics of hydrothermal vents to the intricate machinery of life that produces ATP, as if that is how “life got launched,” given “a free gift of geochemistry on a wet, rocky, and tectonically-active planet.”  From there, Branscomb launched himself into an egregious display of personification:

“It’s only later when life set out to take its act on the road that it had to figure out how to make its own membranes, pump protons uphill across these new membranes, tap into other sources of energy to do the pumping, etc.,” Branscomb said. “But once hooked on the free stuff, the trans-membrane proton gradient in particular, life never broke the habit. And here we are, every living thing, still frantically pumping protons as if just staying alive depends on it—which it does.”