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No entailing laws, but enablement in the evolution of the biosphere
Giuseppe Longo, Maël Montévil, Stuart Kauffman
TL;DR
The paper argues that physics-style entailing laws cannot account for biological evolution because evolution changes its own relevant possibilities and contexts. By contrasting biological histories with physical symmetries and conservation laws, it develops enablement as a framework for understanding evolution's indeterminacy, emergence, and non-conservation.
Problem
Physics-style laws, differential equations, and boundary conditions do not entail the evolution of life because biological niches and the evolutionary phase space are continually changing and unprestatable.
Method
The paper contrasts physical phase spaces, symmetries, and conservation laws with biological symmetry changes, historical dependence, molecular non-ergodicity, and mutation-selection dynamics.
Results
The paper concludes that no physical-style law entails the biosphere's evolution, which combines indeterminate random events with non-random historical outcomes beyond quantum or classical physics alone.
Takeaways & Limitations
Biological evolution requires a theoretical framework centered on changing possibilities, historical symmetry changes, and enablement rather than conserved trajectories and entailing laws.
Takeaways & Limitations
Causal claims are restricted to correlations of differences, so a mutation associated with a disorder does not identify a gene as determining intelligence.
Abstract
from arXiv · showhide
Biological evolution is a complex blend of ever changing structural stability, variability and emergence of new phenotypes, niches, ecosystems. We wish to argue that the evolution of life marks the end of a physics world view of law entailed dynamics. Our considerations depend upon discussing the variability of the very "contexts of life": the interactions between organisms, biological niches and ecosystems. These are ever changing, intrinsically indeterminate and even unprestatable: we do not know ahead of time the "niches" which constitute the boundary conditions on selection. More generally, by the mathematical unprestatability of the "phase space" (space of possibilities), no laws of motion can be formulated for evolution. We call this radical emergence, from life to life. The purpose of this paper is the integration of variation and diversity in a sound conceptual frame and situate unpredictability at a novel theoretical level, that of the very phase space. Our argument will be carried on in close comparisons with physics and the mathematical constructions of phase spaces in that discipline. The role of (theoretical) symmetries as invariant preserving transformations will allow us to understand the nature of physical phase spaces and to stress the differences required for a sound biological theoretizing. In this frame, we discuss the novel notion of "enablement". This will restrict causal analyses to differential cases (a difference that causes a difference). Mutations or other causal differences will allow us to stress that "non conservation principles" are at the core of evolution, in contrast to physical dynamics, largely based on conservation principles as symmetries. Critical transitions, the main locus of symmetry changes in physics, will be discussed, and lead to "extended criticality" as a conceptual frame for a better understanding of the living state of matter.
1 Overview
The paper argues that biological evolution cannot be understood through physical laws that entail dynamics within a prestated phase space, because evolution continually changes and creates unprestatable possibilities. It replaces diachronic causation with enablement while retaining reductive explanations for existing organisms.
- Overview: Biological evolution persistently changes its phase space in ways that cannot be prestated, preventing formulation of fixed equations of motion.The relevant observables, parameters, and adaptive niches emerge only after selection.
- Overview: Enablement replaces diachronic causation as the key relation, describing how contexts make new biological possibilities possible.The analysis restricts causal claims to differential effects while treating niches and ecosystems as enabling conditions.
- Overview: Organisms are analyzed as Kantian wholes whose parts and wholes sustain one another, while molecular reduction remains applicable to synchronic properties of existing organisms.The paper presents this as compatible with, rather than eliminating, reductive accounts of an already evolved heart.
- Overview: The paper contrasts physical conservation-based symmetries with biological trajectories marked by continual symmetry changes.These changes are associated with unprestatable changes in the state space itself.
- Overview: Because evolutionary phase spaces and selective niches are unprestatable, no physical law entails the evolution of the biosphere.The paper also argues that boundary conditions could not be specified for integrating such equations.
2 Physical phase spaces.
Physical theories construct prestated phase spaces from pertinent observables and parameters, then determine trajectories within them. The paper presents these spaces as mathematical frameworks built around invariant properties and contrasts them with biology’s changing phase space.
- Physical phase spaces: In physics, a phase space is a mathematical space defined by pertinent observables and parameters in which trajectories are determined.Examples include position and momentum, energy and time, and Hilbert spaces for quantum states.
- Physical phase spaces: Newtonian and quantum theories use prestated spaces and equations to determine trajectories or probability-density dynamics.In quantum mechanics, measurement introduces indeterminism through projection of the state vector.
- Physical phase spaces: Physics advances by inventing pertinent phase spaces, as illustrated by Newton’s Cartesian framework, Poincaré sections, and thermodynamic observables.These constructions select variables suited to the theoretical description rather than necessarily reducing phenomena to elementary particles.
- Physical phase spaces: Physical phase spaces are organized around invariant properties and symmetry-preserving descriptions, even when nonlinear dynamics limit analytic predictability.The two-body problem can have determined trajectories without generally admitting analytic solutions.
- Physical phase spaces: The paper argues that pre-given phase-space constructions do not apply directly to biology because evolution produces continual, unprestatable changes in the relevant spaces.It develops this contrast through microscopic descriptions, evolution, and symmetry or conservation properties.
3 Biology and microphysical descriptions: non-ergodicity and quantum effects.
The paper argues that biological evolution combines non-ergodic historical constraints with classical and quantum variability, producing phenotypes and observables that cannot be understood from either physics alone. Selection and organismal history restrict possible explorations while new biological levels emerge.
- Non-ergodicity and quantum effects: The finite history of evolution prevents exhaustive exploration of molecular possibilities, so most complex biological forms never exist.The paper uses the enormous combinatorial space of macromolecules and proteins to motivate this claim.
- Non-ergodicity and quantum effects: Biological molecular dynamics are non-ergodic: relevant symmetries depend on history rather than remaining fixed as in statistical mechanics.This makes temporal considerations necessary even for molecular aspects of biological systems.
- Non-ergodicity and quantum effects: The argument is limited to showing that molecular-phase-space ergodicity does not help explain biological dynamics, even if infinite-time ergodicity is allowed.The paper treats this irrelevance as a biological principle rather than denying all possible molecular ergodicity.
- Non-ergodicity and quantum effects: Selection and organismal history restrict possible explorations, with structures such as membranes and nuclei canalizing cellular dynamics.Evolution combines random events with constraints that exclude incompatible explorations.
- Non-ergodicity and quantum effects: Quantum mutations can be amplified by classical dynamics, yielding evolution that is both indeterminate and non-random.The independently evolved similarity of octopus and vertebrate camera eyes is given as an example.
- Non-ergodicity and quantum effects: Random molecular events can generate new phenotypic observables that persist when compatible with an organism’s ecosystem and changing coherence structure.These observables become subject to Darwinian selection at the population level.
4 Kantian whole and selection
The paper treats cells and organisms as Kantian wholes whose functions arise through relations among parts, wholes, and ecosystems rather than through elementary components alone. Selection reveals new functions and co-constitutes the organism’s niche, making the relevant biological phase space continually unprestatable.
- Kantian whole and selection: The paper rejects the assumption that biology’s fundamental objects must be molecular, emphasizing that cells are already complex Kantian wholes.It also notes that physics itself does not always equate fundamental explanation with elementary reduction.
- Kantian whole and selection: In a Kantian whole, parts perform functions defined by their roles in sustaining the whole, while the whole exists through relations among its parts.The relevant functional degrees of freedom cannot be understood through the parts alone.
- Kantian whole and selection: Because newly relevant observables and parameters arise in the evolving biosphere, equations of motion cannot be written for them as they can in predefined physical phase spaces.This supports the paper’s central distinction between biological evolution and physical entailment.
- Kantian whole and selection: The paper defines enablement as the role of a part in forming a new observable, or mathematically, a new dimension of the phase space.The notion is introduced to describe how biological possibilities become available without being entailed by prior laws.
- Kantian whole and selection: Selection acts on the whole organism in its environment and reveals novel functions and ecosystem interactions only after they succeed.The resulting task closure is co-constituted by the organism and its niche.
- Kantian whole and selection: The biological phase space consists of observables and parameters pertinent to Darwinian evolution, including functions that emerge through selection.These components are continually new and cannot be prestated in advance.
5 Examples
The examples illustrate Darwinian preadaptation: existing structures acquire new functions in newly encountered environments, while the resulting niches open further evolutionary possibilities that cannot be listed in advance.
- Darwinian preadaptation: Darwinian preadaptations arise when existing organismal features become compatible with a new selective environment and are thereby enabled.The paper distinguishes this enablement from an entailing physical law.
- Swim-bladder example: A swim bladder evolved from lung-fish lungs after water entered some lungs, producing the new function of neutral buoyancy.The example presents a prior structure as poised to acquire a different use.
- Unprestatable possibilities: The possible preadaptations and selective environments of future evolution cannot be completely named or prestated.The paper uses human evolution over the next three million years as an illustration.
- Adjacent possible: Once a swim bladder exists, it creates an empty adjacent possible niche that can enable organisms such as worms or bacteria to evolve into it.The new niche changes future boundary conditions without itself being selected as a niche.
- Additional example: The middle ears of vertebrates are presented as another preadaptation, arising from bones of the double jaw and acquiring the function of hearing.This is described as a bricolage of old structures into a new function.
6 Symmetry
The paper presents physical phase spaces as constructed from observables associated with invariants and symmetries, making trajectories mathematically describable within a defined background space.
- Phase-space construction: Physics constructs phase spaces from pertinent observables and parameters that specify trajectories.Examples include momentum with position and energy with time.
- Phase-space construction: Physical theory identifies key observables as relative invariants and uses them to construct the intended phase space.The section summarizes this development as first extracting observables, then building the space from them.
- Theoretical status: Physical spaces are effective theoretical inventions rather than absolute spaces already existing beneath phenomena.The paper contrasts this construction with a biological phase space that cannot be treated in the same way.
- Symmetry: Symmetries are invariant properties and invariant-preserving transformations that support mathematical descriptions of physical spaces.This role allows even infinite-dimensional spaces to be handled synthetically.
- Scientific objectivity: The construction of scientific observables requires specifying a reference system or phase space and a metric for measurement.The paper uses this point to motivate its later treatment of phenotypes as biological observables.
7 Changing symmetries
The paper argues that biological evolution continually changes its symmetries, observables, and phase space, so physics’ pre-given mathematical framework cannot simply be transferred to biology.
- Motivation: The authors frame their analysis as a response to physicalist approaches that transfer theories of inert matter to living systems.They develop the comparison with physics while moving toward a biological account.
- Critical transitions: Critical transitions change the symmetries of a system, with some symmetries broken and others newly obtained after the transition.The section treats critical transitions as the paradigmatic setting for symmetry change.
- Changing symmetries: Evolutionary trajectories are described as cascades of critical transitions involving continual symmetry changes.Because the relevant phase space cannot be formally pre-defined, scientific analysis must use different terms.
- Biological niches: Niches are historically co-constructed and may require new names and meanings for newly unprestatable functions.The paper therefore treats complete descriptions of actual and potential niches as potentially incompressible.
- Conclusion: The authors conclude that physics’ methods for pre-defining phase spaces from observables and invariants do not apply to biology.This conclusion concerns the transfer of the physical framework, not the possibility of scientific analysis itself.
- Changing observables: In biology, interactions and boundary conditions can co-define new observables, making phase-space construction circular at a metatheoretical level.The issue is which observables and variables should enter the equations in the first place.
8 Enablement, causality, and randomness
The paper replaces physical entailment with enablement and restricted differential causation, arguing that evolving organisms and niches co-constitute biological possibilities beyond conservation-based prediction.
- Physics worldview: The paper argues that changing biological symmetries terminate the flat transfer of physico-mathematical methods from physics to biology.It links this claim to the unprestatable phase space and sample space of evolution.
- Enablement: Enablement describes how Kantian wholes co-create their worlds so they can exist in the non-ergodic universe above the atomic level.This is offered as the paper’s scientific response to the limits of physicalist certitudes.
- Enablement: Evolution enables forthcoming states rather than causing them in the sense of entailed physical trajectories.The paper proposes replacing entailed causal relations with enablement relations in evolutionary biology.
- Causality: A niche can enable survival of an otherwise incompatible form, while a mutation may serve as the differential cause of the phenotypic variation.This distinguishes enabling conditions from a causal difference that changes the phenotype.
- Causal scope: The paper warns that a mutation associated with a disorder does not establish that the affected gene determines a broad trait such as intelligence.The authors characterize this inference as incorrectly reversing a one-way causal correlation of differences.
- Randomness and conservation: Biological evolution is said to involve non-conservation principles, while physical conservation or optimality properties cannot generally determine an organism’s evolutionary trajectory.Physical forces may shape some organs locally where matter or energy exchange dominates.
- Biological comparison: Different phenotypes can answer the same physical context in incomparable ways, so biological functions cannot generally be ranked by a real-valued optimum.The paper connects this incomparability to the partial independence and co-constitution of niches.
9 Conclusion
The conclusion argues that biological evolution cannot be entailed by physical laws because its phase space, symmetries, and niches change unpredictably. It proposes enablement and co-constitution as a framework for understanding the biosphere’s radically emergent becoming.
- 9 Conclusion: Biological evolution lacks a finite, prestated phase space because possibilities arise through unpredictable sequences of symmetry breakings within changing ecosystems.This contrasts with physical trajectories characterized by invariant or conserved properties.
- 9 Conclusion: Living systems do not follow fixed geodetic trajectories; they maintain themselves within an extended critical interval by changing their phenotypes and observables.The interval is bounded by the edge of death, while organisms adjust to and sometimes change their environments.
- 9 Conclusion: The biosphere’s becoming is enabled through Kantian wholes that co-constitute organisms, niches, and environments, generating new future possibilities beyond selection alone.Enablement describes a web in which living systems co-create conditions for their existence in a non-ergodic universe.
- 9 Conclusion: The paper presents Kantian wholes making worlds together as a positive scientific approach beyond entailing laws for analyzing the biosphere’s complexity and organization.It connects this approach to studying the growth of the adjacent possible through ever-new niches.
- 9 Conclusion: At the watershed of life, the authors conclude that the world “bubbles forth,” rather than unfolding entirely through laws that entail its becoming.This conclusion is framed as the endpoint of the physics worldview of entailing dynamics.