PHILOSOPHY OF ORIGINS · SELECTION AND EXPLANATION

Before heredity:
what can selection explain?

Selection can preserve and improve certain systems once the relevant conditions exist. Explaining how those conditions arose is a further causal task.

This essay develops the challenge raised in Otangelo Grasso’s library thread, There was no prebiotic selection to get life originating. Its central concern is that appeals to natural selection can assume the organized reproduction they are meant to explain. The argument deserves a precise formulation: ordinary chemical discrimination, competition, and heritable selection are different processes, with different explanatory powers. ¹

The objection: do not assume the outcome

Modern organisms inherit structures and sequences that contribute to their reproduction. An explanation of the first such system cannot begin by granting a complete genome, translation apparatus, membrane-maintenance network and reliable copying machinery, then invoke selection to explain their arrival. What is supplied at the start must be stated and independently justified.

The library’s strongest challenge is therefore a problem of explanatory circularity. If a proposed beneficial molecule can be retained only by a mechanism that already requires that molecule’s function, the account needs an earlier, simpler arrangement or a different causal route. Naming a future advantage does not make it available to a system that cannot yet produce, retain or transmit the relevant feature. ¹

This does not establish that no physical sorting occurred before life. Nor does the word “selection” imply a conscious chooser whenever it is used in chemistry or biology. The question is what causal process actually sorts, propagates or preserves the material—and whether that process can support the historical transition being claimed.

Four meanings that must be kept separate

Process	What happens	What it does not establish alone
Chemical sorting	Different reaction rates, solubilities, surface affinities or stabilities change a mixture.	Inheritance of useful functions or cumulative adaptation.
Differential persistence	Some molecules or assemblies remain longer under specified conditions.	That the more persistent material is better at creating a heritable functional system.
Amplification and competition	Products accumulate at different rates or competing assemblies acquire resources unequally.	A durable link between an advantage and descendants across repeated cycles.
Selection with heredity	Transmitted differences affect propagation, so variants change in representation over generations.	The origin of every prerequisite for that propagation, or unlimited capacity for innovation.

Sorting can enrich useful material, unhelpful material, or both. Persistence may preserve a promising intermediate, but can also favor an inert end product. Fast amplification can favor a short parasite rather than a catalyst beneficial to a larger network. The direction of change must be demonstrated; “the fittest survives” is empty unless fitness is defined through a measurable process.

A nonliving mixture need not be chemically indiscriminate. However, differential abundance is a weaker result than the establishment of a lineage in which functional differences remain associated with their consequences. That distinction preserves the substance of the library’s objection without denying ordinary physical chemistry.

What must exist for cumulative selection?

A proposed selectable system needs identifiable variants, a route of propagation, transmission of relevant differences, and a connection between those differences and differential success. These requirements do not demand a modern bacterial cell. They do demand a physical implementation. A copying RNA, a compositionally inherited network and a dividing compartment are different candidates, each with distinct failure modes. ²

Consider a catalyst that improves resource production inside a compartment. Its product must benefit that compartment for long enough to affect growth or division. The catalyst, or the capacity to remake it, must reach descendants. If the product leaks away immediately, the advantage may be shared with competitors. If the catalyst is diluted out, the benefit can disappear after one generation. A one-cycle advantage and sustained cumulative improvement are different achievements.

Heredity can initially be imperfect, but must be sufficient for the target process. Excessive copying errors can erase useful sequence information. Conversely, a system that copies accurately but has no route to useful variation or resource renewal may be unable to expand its functions. A credible account must examine these coupled conditions under compatible circumstances, rather than solve each in a different environment without connecting them.

What experiments and models actually show

Competition without demonstrated heredity

Adamala and Szostak’s 2013 study linked a catalyst inside fatty-acid vesicles to production of a membrane-associated peptide and enhanced competitive growth. This demonstrated a physical connection between internal chemistry and compartment growth. The authors explicitly noted that their catalyst was not heritable and the system could not yet evolve. It is evidence for a component of a proposed transition, not a reconstruction of that entire transition. ³

A replicating RNA system in the laboratory

Lincoln and Joyce’s 2009 work demonstrated cross-replicating RNA enzymes assembled from supplied RNA fragments, with amplification and competition. It shows that replication and selectable differences can occur in a molecular system without a modern cell. Its prepared catalysts, substrates and maintained conditions are important starting provisions; the experiment does not demonstrate their spontaneous availability on early Earth. ⁴

A 2026 model of growth and information

Nunes Palmeira and colleagues modeled how growth and informational functions could improve together in protocells. Their starting system includes rudimentary metabolism, dividing compartments and RNA that can be copied and loosely translated into peptides. The results identify conditions favoring growth functions before improved information propagation within that model. They do not derive every starting capability from unorganized feedstocks or experimentally reconstruct the modeled chemistry. ⁵

The correct questions are the same in each case: Which step was achieved? Which functions were supplied? What intervention maintained the system? Which proposed environmental process could replace that intervention? A prepared experiment can establish a mechanism; additional evidence is needed to establish its prebiotic accessibility. A model can expose a possible dependency or constraint; its assumptions are not themselves experimental findings.

The explanatory work that remains

A pathway from prebiotic chemistry to heritable function must connect several kinds of achievement. Relevant questions include the availability and concentration of starting materials; activation and replenishment of substrates; selectivity against competing reactions; polymer formation and degradation; copying, strand separation and repeat cycles; compartment compatibility; and transmission of useful activity. These are linked questions, not independent probabilities to multiply without a justified model. Reviews of protocell research explicitly examine compatibility and replication challenges. ^{2, 6}

The retention problem. How does an improvement persist long enough to contribute to the next step? A useful reaction occurring once is insufficient if its products disappear or cannot be regenerated.

The association problem. How does a benefit remain linked to the entity responsible for it? Compartments can localize benefits, but their growth, permeability, division and inheritance must operate together.

The direction problem. Why should the immediate advantage lead toward the later system? Selection has no foresight. A step cannot be credited with a benefit that becomes available only after absent downstream machinery appears.

The continuity problem. Can successive stages work under conditions connected by plausible changes in location or environment? Successful reactions in separate laboratory settings do not automatically constitute a continuous historical route.

These questions specify research targets. Their unresolved status in a particular proposal is a limitation of that proposal. Demonstrating that all natural routes are impossible would require a much broader argument than identifying a gap in one route.

Hallmarks, agency and abductive assessment

The design-relevant observation emphasized by the atlas is the coordination of inherited specification, functional production, energy use and maintenance. In bacteria, these capacities are realized in concrete molecular interactions; the ribosome account examines one major dependency network. Grasso’s framework interprets coordinated specification and implementation as suggestive of agency. The relevant information hallmarks and heredity and quality-control hallmarks identify what should be investigated.

The positive argument is that known agents can select components with future functional requirements in view and arrange cooperating processes. Its limit is that similarity to engineered organization does not identify the historical cause of every biological feature. A design hypothesis also needs constraints and discriminating expectations. Missing heredity in a natural scenario cannot, by itself, establish an intelligent intervention.

A cautious inference. The author regards the convergence of specification, construction and reliable transmission as grounds for considering coordinated design. The prebiotic-selection objection strengthens the demand that alternatives explain the origin of their selectable systems. It does not establish that all prebiotic discrimination is absent or that natural mechanisms could never cross the heredity threshold. Comparative confidence must track demonstrated pathways, justified starting conditions and independent evidence for agency. The abductive framework explains how to state that assessment without assigning unsupported numerical odds.

What would resolve the disagreement?

A strong natural demonstration would connect credible feedstocks and conditions to a system that repeatedly propagates, transmits functional differences and retains improvements without the investigator supplying the decisive missing step. The exact target must be specified: demonstrating primitive heredity would answer a narrower question than constructing a fully autonomous bacterium.

A strong design case would offer evidence that distinguishes intentional coordination from realistic alternatives, beyond a general appeal to present complexity. Conversely, reproducible intermediate systems that remove a claimed dependency barrier would weaken that particular design argument. Partial achievements should change assessments in proportion to what they actually establish.

The defensible conclusion is that cumulative selection cannot be invoked without explaining its physical prerequisites. Chemical sorting and partial molecular selection are real phenomena, but their reach must be demonstrated. The origin of a heritable, integrated system is the explanatory target; the word “selection” is the beginning of a mechanistic question, not its answer.

References and further reading

The library thread supplies the motivating argument. Research papers and reviews support the experimental and modeling descriptions; the philosophical synthesis is developed here.

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Before heredity:what can selection explain?