Stuart Kauffman, Giuseppe Longo & Maël Montévil: “No Entailing Laws, But Enablement in the Evolution of the Biosphere” (2012) Abstract: “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 in- variant 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’. Life lives in a web of enablement and radical emergence. 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 aim of this article is to demonstrate that the mode of understanding in physics since Newton, namely differential equations, initial and boundary conditions, then integration which constitutes deduction, which in turn constitutes ‘entailment’, fails fundamentally for the evolution of life. No law in the physical sense, we will argue, entails the evolution of life. If we are correct, this spells the end of ‘strong reductionism’, the long held belief that a set of laws ‘down there’ entails all that happens in the universe. More, if no law entails the evolution of life, yet the biosphere is the most complex system we know of in the universe, it has managed to come into existence without an entailing law. Then such law is not necessary for extraordinary complexity to arise and thrive. We need new ways to think about how current life organization can have come into being and persists. Those ways include coming to understand how what we will call organisms as ‘Kantian wholes’ co-create their worlds with one another. “The heart of our considerations are these: 1) In physics, we can prestate the configuration space or phase space, a crucial notion in this paper. Dynamics are geodetics within such prestated phase spaces, which may be very abstract, like in Quantum Mechanics. 2) In biological evolution, the phase space itself changes persistently. More it does so in ways that cannot be prestated. 3) Because we cannot prestate the ever changing phase space of biological evolution, we have no settled relations by which we can write down the ‘equations of motion’ of the ever new biologically ‘relevant observables and parameters’ revealed after the fact by selection acting on Kantian wholes in biological evolution, but that we cannot prestate. More, we cannot prestate the adaptive ‘niche’ as a boundary condition, so could not integrate the equations of motion even were we to have them. 4) If the above is true, no law entails the evolution of the biosphere. 5) If by ‘cause’, we mean what gives a differential effect entailed by law, then we can assign no cause in the ‘diachronic’ evolution of the biosphere. 6) In place of ‘cause’ in this diachronic evolution, we will find ‘enablement’, ie making possible – a key notion in our analysis. 7) Our thesis does not obviate reductive explanations of organisms as synchronic entities, such as an ultimate physical account of the behavior of an existing heart, once evolved. “Our analysis is centered on cells and organisms as Kantian wholes, where the whole exists for and by means of the parts, and the parts for and by means of the whole. Given a Kantian whole, the ‘function’ of a part in sustaining the whole is definable. Other synchronic causal consequences are irrelevant side effects. An essential feature of our analysis is that at levels of complexity above the atom, for example for molecules, the universe is grossly non-ergodic, that is it does not explore all possible paths or configurations. We will not make all possible proteins length 200 amino acids in 10 to the 39th times the lifetime of the universe, even were all 10 to the 80th particles making such proteins on the Planck time scale. Thus, the existence in the universe of a heart, which Darwin tells us is due to its selective advantage in a sequence of descendant, Kantian whole organisms, is physically important: Most complex things will not ever exist. Thus Darwin’s theory is telling us how hearts exist in the universe. Kantian wholes, married to self reproduction and Darwinian evolution, are part of the non-ergodic, historical becoming of the universe, and, we claim, beyond entailing law. A deep aspect of the freedom from entailing law in the evolution of organisms is that the possible ‘uses’ of a given part or process of an organism are, both indefinite and unoderable, in our views, thus, a fortiori, no effective procedure, or algorithm can list them. Thus when selection acts at the level of the whole organism, we cannot have pre-listed the newly relevant functional features of its parts revealed by selection. It follows that we cannot prestate the ever changing relevant observables and variables revealed by selection, so — our main theme — cannot write equations of motion for the evolving biopshere. Nor can we in general prestate the boundary conditions on selection, i.e. the ‘niche’, so we could not integrate the equations of motion that we do not have anyway. In short, no law entails the evolution of the biosphere, nor, more specifically, of an organism phylogenetic trajectory. Moreover, we claim, niches and ecosystems ‘enable’ the formation of life, and causal relations should be seen only in differential effects. “The key argument will be given in reference and contrast to the role of symmetries and conservation laws in physics. We will show that symmetries and the mathematics of invariants and invariant preserving transformations cannot be transferred as such to suitable theoretical frames for biology, in particular to analyses of biological evolution. We will note that the construction of phase spaces for physics has been largely, or even exclusively, based on invariant properties of ‘trajectories’, ie on symmetries. This fails in biological theoretizing, since phylogenetic trajectories may be view as continual symmetry changes. In our perspective, These continual symmetry changes are correlated to unprestatable changes of the state space itself. Of course, the key point, extensively stressed below, is the proposal of the suitable observables in biology. These are dictated by the chosen theory. For us, this is Darwin’s Evolution. “In this theoretical frame, we cannot prestate or list the possible selective biological environments, in view of the provable impossibility to prestate the intended ‘coherence structures’ and their symmetries. As a consequence, the set of objects or processes able to carry out a given use, or Kantian function, is also indefinite and unorderable, so not enumerable. But such ever novel parts and processes as adaptations and Darwinian preadaptations arise all the time, often by quantum indeterminate, acausal, random mutations, and find a use, and often a novel function as parts in the organism in an unprestatable selective environment, so are grafted into the organism, thereby changing the phase space of evolution, we will argue, in an unprestatable, incompressible, way. Concurrently, we note that we can think of a reproducing cell or organism as achieving a ‘task closure’ in some set of tasks, such as mitosis, the behavior of chemosmotic pumps and so on. But this task closure is achieved via the biotic and abiotic environment. But only selection acting at the level of the Kantian wholes, reveals after the fact, the newly relevant features of the organism and the environment that constitute the task closure and the new ‘niche’ of the now surviving organism. In short, the organism and its niche, are co-constituted in a circular way that cannot be prestated. Again, we will argue that no laws of motion, nor boundary condition to integrate such laws were we to have them, can be formulated. No law entails the evolution of the biosphere. “Finally, and stunningly, evolution creates, without selection acting to do so, new ‘adjacent possible empty niches’ which enable new possible directions of evolution. This is radical emergence from life to life. Further, the evolution of a new organism to live in a new ‘adjacent possible empty niche’, often arises due to one or a sequence of quantum events, at the molecular level, which are acausal. Thus the niche does not cause, but ‘enables’ the radical emergence. Not only is life caught in a web of causes, it is part of a co-constituting web of enablement and radical emergence. “If correct, reductionism reaches a terminus at the watershed of life. With Heraclitus we say of life: The world bubbles forth. ... 3 Biology and microphysical descriptions: non-ergodicity and quantum effects. ... “As mentioned in the overview, an easy combinatorial argument shows that even at the TIME scale of the Universe, all possible macromolecules, or even proteins of length 200 amino acids cannot be explored. So, their ‘composition’ in a new organ or organism (thus, in a phenotype) cannot be the result of the ergodicity of physical dynamics3. Because of this non-ergodicity, history enters. More, most complex things will never exist. Later, in discussing Kantian wholes where the parts exist for and by means of the whole and the whole for and by means of the parts, the physical relevance is that in the non-ergodic universe, hearts and humans, via evolution, do exist in the universe. ... “As for biology, evolution is both the result of random events at all levels of organization of life and of constraints that canalize it, in particular by excluding, by selection, incompatible random explorations. So, ergodic explorations are also restricted or prevented both by selection and the history of the organism. For example, the presence and the structure of a membrane, or a nucleus, in a cell canalizes also the whole cellular activities along a restricted form of possible dynamics. “We find it critical that neither quantum mechanics alone, nor classical physics alone, account for evolution. Both seem to work together. Mutations can be random, acausal, indeterminate quantum events. Yet, they may interfere or happen simultaneously to or be amplified by classical dynamics. In this amplification, evolution is also not random, as seen in the stunning similarity of the octopus and vertebrate camera eye, independently evolved. Thus evolution is both indeterminate, random and acausal, and yet non random. It is indeed not sufficiently described by quantum mechanics alone or classical mechanics alone. Life is new. ... “When a (random) quantum event at the molecular level (DNA or RNA-DNA or RNA-protein or protein-protein) has consequences at the level of the phenotype, the somatic consequences may persist if they are compatible with the ecosystem and with the ever changing ‘coherence structure’ of the organism as constructed along its history. In particular, it may allow the formation of a new function, organ or tool or different use of an existing tool, thus to the formation of a new properly relevant biological observable. This new observable has at least the same level of unpredictability as the quantum event, but it does not belong to the quantum phase space: it is subject to Darwinian selection at the level of a population, typically, thus it interacts with the ecosystem as such. This is the pertinent level of observability, the space of phenotypes, where biological randomness and unpredictability is now to be analyzed. “Note also that the effects of the classical/quantum blend may show up at a different level of observability and may retroact. First, a mutation or a random difference in the genome, may contribute to the construction of a new phenotype. Second, this phenotype may retroact downwards, to the molecular (or quantum) level. A molecular activity may be excluded, as appearing in cells (organs/organisms) which turn out to be unfit — selection acts at the level of organisms; methylation and demethylation downwards modify the expression of ‘genes’.... 4 Kantian whole and selection “Before specifying further our approach to biological objects, we have first to challenge the Cartesian and Laplacian view that the fundamental is always elementary and that the elementary is always simple. According to this view, in biology only the molecular analysis would be fundamental. “Galileo and Einstein proposed fundamental theories of gravitation and inertia, with no references to Democritus’ atoms nor quanta composing their falling bodies or planets. Then, Einstein, and still now physicists, struggle for unification, not reduction of the relativistic field to the quantum one. Boltzmann did not reduce thermodynamics to Newton-Laplace trajectories of particles.... ... “Moreover, the proper elementary observable doesn’t need to be simple. ‘Elementary particles’ are not conceptually/mathematically simple, in quantum field theories nor in string theory. In biology, the elementary living component, the cell, is (very) complex, a further anti-Cartesian stand at the core of our proposal: a cell is already a Kantian whole. “As a matter of fact, Kant pointed out that in an ‘organized being’ the parts exist for and by means of the whole, the whole exists for and by means of the parts. The parts perform tasks, typically subsets of their causal consequences, that can be defined only because they are part of a Kantian whole. No reduction to the parts allows understanding of the whole because the relevant degrees of freedom of the parts as associated to the whole are functional (compatibility within the whole and of the whole in the ecosystem) and definable as components of the causal consequences of physical properties of the parts, while the microscopic degrees of freedom of the parts are understood as physical. By this, they include all the causal consequences of the parts. Further, because of the non-ergodicity of the universe above the level of atoms, where most molecules and organs will never exist, a selective account of the function of a part of a Kantian whole that participates in the continued existence of that whole in the non-ergodic universe has concrete physical as well as biological meaning. More, in a sense, ergodicity would prevent selection since since [sic] it would mean that a negatively selected phenotype would ‘come back’ anyway. ... “In biology, we consider observable and parameters that are derived from or pertinent to Darwinian evolution and this is fundamental for our approach. Their very definition depends on the intended Kantian whole and its integration in AND regulation by an ecosystem. Selection, acting at the level of the evolving Kantian whole in its environment, selects on functions (thus on and by organs in an organism) as interacting with an ecosystem.... “Consider for example the crystalline in a vertebrate eye, or the kidney. Both these organs and their functions did not exist before the organisms with crystalline and kidneys were formed. Thus, if we consider the proper biological observable (crystalline, kidney), each phenotypic consequence or set of consequences of a chemical (enzymatic) activity has an a priori indefinite and unorderable, hence algorithmically undefinable set of potential uses, not pre-definable in the language of physics. Similarly, a membrane bound small protein serving a different function, which by Darwinian preadaptation or Gould’s exaptation, may latter become part of the flagellar motor of a bacterium; similarly the double jaws of some vertebrate of 200 million years ago will yield the middle ear bones of today’s vertebrates. There was no mathematical need for the phenotype nor for the function, ‘listening’, in the physical world. In short, for any single or indefinite set of parts and processes, their causal and quantum relations may find some use alone or together, which may allow or increase the capacity of the living being to survive in a new selective environment.... “Organisms withstand the intrinsic unstability/unpredictability of the changing phase space, by their relative autonomy. They have an internal, permanently reconstructed autonomy, in Kant’s sense, or Varela’s autopoiesis, that gives them an ever changing, yet ‘inertial’ structural stability. They achieve a closure in a task space by which they reproduce, and evolve and adapt by processes alone or together out of the indefinite and unorderable set of uses, of finding new uses to sustain this in the ongoing evolution of the biosphere. These uses are indefinite as they constitute, when viable, new biological functions and organs, depending on the context. We will formulate this in a physico-mathematical way in section. They are unorderable, since variability and diversity manifests itself as the ‘branching’ of evolution, where structure and function of the resulting organs and organisms are on different branches and, by this, uncomparable — both notions are, of course, epistemic, as we may ‘ locally’ propose phase spaces and order, whenever this adds to intelligibility of nature. “This situation leads us to introduce the notion of enablement, that we will first define as the role played by a part with respect to the formation of a new observable (mathematically, a new dimension) of the phase space.... ... 5 Examples ... “This leads to both enablement and radical emergence: The swim bladder was probably selected in a population of fish to function as a swim bladder, but the swim bladder itself as a new adjacent possible empty niche was not selected as a niche, as such. Yet it changes the possible directions of evolution as a worm or bacterium may evolve to live in it. But this means that jointly to but beyond selection, the biosphere creates, by variability, recombination and new unpredictable uses, its own possibilities of future evolution, that is radical emergence of life from life. Further, both in the sense that quantum acausal processes of mutation may underlie the evolution of the worm, and the deeper fact that no law entails the evolution of the biosphere, the new adjacent possible empty niche does not ‘cause’, but does ‘enable’ the emergence of a new direction in the evolution of the biosphere. ... 7 Changing symmetries ... “...Even worse, in quantum fields theories, the parts are not really separable from the whole (this would mean to separate an electron from the field it generates) and there is no relevant elementary scale which would allow ONE to get rid of the infinities (and again this would be quite arbitrary, since the objectivity needs the inter-scale relationship)... “In short, even in physics there are situations where the whole is not the sum of the parts because the parts cannot be summed on (this is not specific to quantum fields and is also relevant for classical fields, in principle). “As for criticality in biology, there exists substantial empirical evidence that living organisms undergo critical transitions... These are mostly analyzed as limit situations, either never really reached by an organism or as occasional point-wise transitions. Or also, as researchers nicely claim in specific analysis: a biological system, a cell genetic regulatory networks, brain and brain slices . . . are ‘poised at criticality’... In other words, critical state transitions happen continually. ... “As for evolution, there is no possible equational entailment nor a causal structure of determination derived from such entailment, as in physics. the point is that these are better understood and correlated, since the work of Noether and Weyl in the last century, as symmetries in the intended equations, where they express the underlying invariants and invariant preserving transformations. No theoretical symmetries, no equations, thus no laws and no entailed causes allow the mathematical deduction of biological trajectories in pre-given phase spaces — at least not in the deep and strong sense established by the physico-mathematical theories. Observe that the robust, clear, powerful physico-mathematical sense of entailing law has been permeating all sciences, including societal ones, economics among others. If we are correct, this permeating physico-mathematical sense of entailing law must be given up for unentailed diachronic evolution in biology, in economic evolution, and cultural evolution. “As a fundamental example of symmetry change, observe that mitosis yields different proteome distributions, differences in DNA or DNA expressions, in membranes or organelles: the symmetries are not preserved. In a multi-cellular organism, each mitosis asymmetrically reconstructs a new coherent ‘Kantian whole’, in the sense of the physics of critical transitions: a new tissue matrix, new collagen structure, new cell-to-cell connections . . . . And we undergo millions of mitosis each minute. More, this is not ‘noise’: this is variability, which yields diversity, which is at the core of evolution and even of stability of an organism or an ecosystem. Organisms and ecosystems are structurally stable, also because they are Kantian wholes that permanently and non-identically reconstruct themselves: they do it in an always different, thus adaptive, way. They change the coherence structure, thus its symmetries. This reconstruction is thus random, but also not random, as it heavily depends on constraints, such as the proteins types imposed by the DNA, the relative geometric distribution of cells in embryogenesis, interactions in an organism, in a niche, but also on the opposite of constraints, the autonomy of Kantian wholes. “...And the change of a (major) function induces a change in the global Kantian whole as a coherence structure, that is it changes the internal symmetries: the fish with the new bladder will swim differently, its heart-vascular system will relevantly change . . . . “Organisms transform the ecosystem while transforming themselves and they can stand/do it because they have an internal preserved universe (Bernard’s ‘milieu interior’).... “Consider, say, a microbial ecosystem in a human. It has some 150 different microbial species in the intestinal tract. Each person’s ecosystem is unique, and tends largely to be restored following antibiotic treatment. Each of these microbes is a Kantian whole, and in ways we do not understand yet, the ‘community’ in the intestines co-creates their worlds together, co-creating the niches by which each and all achieve, with the surrounding human tissue, a task closure that is ‘always’ sustained even if it may change by immigration of new microbial species into the community and extinction of old species in the community. With such community membership turnover, or community assembly, the phase space of the system is undergoing continual and open ended changes. Moreover, given the rate of mutation in microbial populations, it is very likely that these microbial communities are also co-evolving with one another on a rapid time scale. Again, the phase space is continually changing as are the symmetries. ... 8 Enablement, causality, and randomness 8.1 The Terminus of a Physics Worldview at the Watershed of Life “The instability of biological theoretical symmetries is not, of course, the end of science, but it is the terminus of the flat transfer of physico-mathematical methods of physics, taught us from Newton onward, to biology. In biological evolution we cannot use the same very rich interaction with mathematics at the core of physical theories. Consequently, our analysis, if correct, puts an end, a fortiori, to any form of reductionism, either to existing physical theories or to the even simpler theories of information, either Shannon or Turing, both embedded in the fragments of current mathematics dealing with discrete structures and data types, whose phase spaces are even more strictly pre-given. Because the ever changing phase space of biological evolution cannot be prestated and its sample space is not statable, one cannot compute ‘the entropy of the Source’, a la Shannon, nor can one define the algorithmic generation of a sequence of prestated symbols, a la Turing. “The scientific answer we propose to this end of the physicalist certitudes, is based on an analysis of the notion of ‘enablement’ in evolution (and ontogenesis, to be discussed elsewhere). In turn the enablement concerns how Kantian wholes co-create their worlds such that they can exist in the non-ergodic universe above the level of atoms. “Our thesis then is that evolution as a ‘diachronic process’ of becoming (but ontogenesis as well) just ‘enables’, but does not cause, the forthcoming state of affairs... Typically, a niche enables the survival of an otherwise incompatible/impossible form of life, it does not cause it.... ... 8.2 Causes and Enablement “Since symmetries are unstable, causality in biology cannot be understood as ‘entailed causality’ as in physics and this will lead us to the proposal that ‘causal relations are only differential causes’. If a bacterium causes pneumonia, or a mutation causes one of the rare monogenetic diseases (anemia falciformis, say), this is a cause and it is differential, i. e. it is a difference with respect to what is fairly considered ‘normal’ and causes an anormality in the phenotype. “A classical mistake is to say: this mutation causes an idiot child (a famous genetic disorder, phenylketonuria), thus . . . the gene affected by the mutation is the gene of intelligence, or: here is the gene that causes/determines the intelligence. In logical terms, it consists in deducing from ‘notA implies notB’, that ‘A implies B’: an amazing mistake. All that we know is a causal correlation of differences. “We then propose to consider things differently. The single observed or induced difference, a mutation with a somatic effect, a stone bumping on someone’s head, or a carcinogen (asbestos) does cause a problem; that is the causal dictionary is suitable to describe a differential cause-effect relation. The differential cause modifies the space of possibilites, that is the compatibility of the organism with the ecosystem. In other terms, it modifies the ‘enablement relations’. In some case, the modified frame may be viable. “In other words, the differential causes modify the coherence structure of an organism, a niche, an ecosystem. So enablement is modified: a niche may be no longer suitable for an organism. Either selection may exclude the modified organism or a change in a niche, due to a differential physical cause (a climate change, say), may negatively select existing organisms or act on them differently, since the enablement relations differ. ... “How do biological niches relate to physical boundary conditions? Consider a billiard table with its four edges which are the boundary condition on the motion of a billiard ball. The boundary conditions play a causal role in the motion of the ball, according to Newton’s third law of motion. Hence integration of the laws of motion in differential equations with initial and boundary conditions do yield the future and past trajectories of the ball. Energy as a conserved observable allows us to mathematically describe the dynamics. Consider then an adjacent possible empty niche, say the swim bladder. Is it a boundary condition? Not in the sense as in physics, since the swim bladder enables the worm or the bacterium to live and evolve, according to un-prestatable enabling relations: the features of the swim bladder to be used by the new organism to achieve task closure in its environment may be radically new.... “In other words, we cannot know ahead of time the co-constituted observables (functions, typically) of the worm and swim bladder that allow the worm to live in the swim bladder.... ... 9 Conclusion ... “In this sense, there are no laws that entail, as in physics, the becoming of the biosphere, and a fortiori, the econosphere, or culture or history, or life in general. In the same sense, geodetic principle mathematically forces physical objects never to go wrong. A falling stone follows exactly the gravitational arrow. A river goes along the shortest path to the sea, it may adjust it by nonlinear well definable interactions as mentioned above, but it will never go wrong. These are all geodetics. Living entities, instead, go wrong most of the time... In short, life goes wrong most of the time, but it ‘adjusts’ to the environment and changes the environment, if possible. It maintains itself, always within an extend critical interval, whose limits are the edge of death, by changing the observables, the phenotypes, that is the very nature of the living object. “If we are right in our conclusion, the strong reductionist dream of a theory that entails the full becoming of the universe is wrong. With life, we reach the end of a physics worldview that has dominated us since Newton. Yet the biosphere is magnificant in its enabled, radically emergent becoming, the most complex system we know of in the universe.... As Darwin said, ‘There is a grandeur in this view of life. . . ‘, now seen to be beyond entailing laws. Then we must ask new scientific questions, for this co-constitution by Kantian wholes as they co-evolve and make their worlds together must be a central part of how the biosphere emerges. We do not begin to understand this co-constitution and enabled radical emergent becoming in which the biosphere, jointly to but beyond selection, creates its own future possibilities of becoming. So too does the evolving econosphere and culture. “Kantian wholes making worlds with one another in the biosphere, our approach, is part of a positive science, beyond entailing laws, for why the biosphere is the most complex system we know of in the universe and works so well. And more, we may be able to analyze the growth of the adjacent possible as the ever new niches enabled by the Kantian wholes living together.... “Two thousand five hundred years ago Heraclitus said, ‘The world bubbles forth’. He may not be correct for physics. But at the watershed of life, we agree: Life bubbles forth.” arxiv.org/pdf/1201.2069.pdf
Posted on: Thu, 30 Oct 2014 13:07:14 +0000
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