Emergence in History

7/23/2019 Emergence in History

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EMERGENCE IN HISTORYThe origin of the modern concept of emergence can be traced to the middleof the nineteenth century when realist philosophers rst began pondering thedeep dissimilarities between causality in the elds of physics and chemistry.

The classical example of causality in physics is a collision between twomolecules or other rigid objects. Even in the case of several colliding

molecules the overall eect is a simple addition. If, for example, onemolecule is hit by a second one in one direction and by a third one in adierent direction the composite eect will be the same as the sum of thetwo separate eects the rst molecule will end up in the same nal positionif the other two hit it simultaneously or if one collision happens before theother. In short, in these causal interactions there are no surprises, nothing isproduced over and above what is already there. !ut when two moleculesinteract chemically an entirely new entity may emerge, as when hydrogenand oxygen interact to form water. "ater has properties that are notpossessed by its component parts oxygen and hydrogen are gases at roomtemperature while water is li#uid. $nd water has capacities distinct fromthose of its parts adding oxygen or hydrogen to a re fuels it while adding

water extinguishes it.The fact that novel properties and capacities emerge from a causalinteraction was believed to have important philosophical implications for thenature of scientic explanation. In particular, the absence of novelty inphysical interactions meant that explaining their eects could be reduced todeduction from general principles or laws. !ecause deductive logic simplytransfers truth from general sentences to particular ones without addinganything new it seemed li%e an ideal way of modeling the explanation ofsituations li%e those involving rigid collisions. !ut the synthesis of water doesproduce something new, not new in the absolute sense of something that hasnever existed before but only in the relative sense that something emergesthat was not in the interacting entities acting as causes. This led somephilosophers to the erroneous conclusion that emergent eects could not beexplained, or what amounts to the same thing, that an eect is emergentonly for as long as a law from which it can be deduced has not yet beenfound. This line of thought went on to become a full &edged philosophy inthe early twentieth century, a philosophy based on the idea that emergencewas intrinsically unexplainable. This rst wave of 'emergentist( philosopherswere not mystical thin%ers but #uite the opposite they wanted to use theconcept of emergence to eliminate from biology mystifying entities li%e a 'lifeforce( or the ')lan vital(. !ut their position towards explanation gave theirviews an inevitable mystical tone emergent properties, they said, must beaccepted with an attitude of intellectual resignation, that is, they must betreated as brute facts towards which the only honest stance is one of naturalpiety.Expressions li%e these were bound to ma%e the concept of emergencesuspect to future generations of philosophers. It was only the passage of timeand the fact that mathematical laws li%e those of classical physics were notfound in chemistry or biology * or for that matter, in the more historical eldsof physics, li%e geology or climatology * that would rescue the concept fromintellectual oblivion. "ithout simple laws acting as self+evident truthsaxioms- from which all causal eects could be deduced as theorems the


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axiomatic dream eventually withered away. Today a scientic explanation isidentied not with some logical operation but with the more creativeendeavor of elucidating the mechanisms that produce a given eect. Theearly emergentists dismissed this idea because they could not imagineanything more complex than a linear cloc%wor% mechanism. !ut there aremany other physical mechanisms that are nonlinear. Even in the realm of

human technology we have a plurality of exemplars to guide our imaginationsteam engines, thermostats, transistors. $nd outside technology the diversityis even greater as illustrated by all the dierent mechanisms that have beendiscovered in chemistry and biology. $rmed with a richer concept ofmechanism the emergent properties of a whole can now be explained as aneect of the causal interactions between its component parts. $ large portionof this boo% will be dedicated to describe the wide variety of mechanisms ofemergence that have been elucidated in the decades since the originalemergentists rst wrote.

Thus, what is dierent today from the early twentieth century views is theepistemological status of emergence it does not have to be accepted as abrute fact but can be explained without fearing that it will be explained away.

"hat has remained the same is the ontological status of emergence it stillrefers to something that is objectively irreducible. !ut what %inds of entitiesdisplay this ontological irreducibility The original examples of irreduciblewholes were entities li%e '/ife(, '0ind(, or even '1eity(. !ut these entitiescannot be considered legitimate inhabitants of objective reality because theyare nothing but reied generalities. $nd even if one does not have a problemwith an ontological commitment to entities li%e these it is hard to see how wecould specify mechanisms of emergence for life or mind in general, asopposed to accounting for the emergent properties and capacities of concretewholes li%e a metabolic circuit or an assembly of neurons. The only problemwith focusing on concrete wholes is that this would seem to ma%ephilosophers redundant since they do not play any role in the elucidation ofthe series of events that produce emergent eects. This fear of redundancymay explain the attachment of philosophers to vague entities as a way ofcarving out a niche for themselves in this enterprise. !ut realist philosophersneed not fear irrelevance because they have plenty of wor% creating anontology free of reied generalities within which the concept of emergencecan be correctly deployed."hat %inds of concrete emergent wholes can we legitimately believe in"holes the identity of which is determined historically by the processes thatinitiated and sustain the interactions between their parts. The historicallycontingent identity of these wholes is dened by their emergent properties,capacities, and tendencies. /et2s illustrate the distinction between propertiesand capacities with a simple example. $ %itchen %nife may be either sharp ornot, sharpness being an actual property of the %nife. "e can identify thisproperty with the shape of the cross section of the %nife2s blade if this crosssection has a triangular shape then the %nife is sharp else it is blunt. Thisshape is emergent because the metallic atoms ma%ing up the %nife must bearranged in a very particular way for it to be triangular. There is, on the otherhand, the capacity of the %nife to cut things. This is a very dierent thingbecause unli%e the property of sharpness which is always actual the capacityto cut may never be actual if the %nife is never used. In other words, a


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capacity may remain only potential if it is never actually exercised. Thisalready points to a very dierent ontological status between properties andcapacities. In addition, when the capacity does become actual it is not as astate, li%e the state of being sharp, but as an event, an event that is alwaysdouble to cut+to be cut. The reason for this is that the %nife2s capacity toaect is contingent on the existence of other things, cuttable things, that

have the capacity to be aected by it. Thus, while properties can be speciedwithout reference to anything else capacities to aect must always bethought in relation to capacities to be aected. 3inally, the ontologicalrelation between properties and capacities displays a complex symmetry. 4none hand, capacities depend on properties a %nife must be sharp to be ableto cut. 4n the other, the properties of a whole emerge from interactionsbetween its component parts, interactions in which the parts must exercisetheir own capacities without metallic atoms exercising their capacity to bondwith one another the %nife2s sharpness would not exist.$ similar distinction can be made between emergent properties andtendencies. To stic% to the same example a %nife has the property of solidity,a property that is stable within a wide range of temperatures. 5evertheless,

there are always environments that exceed that range, environments inwhich the temperature becomes so intense that the %nife is forced tomanifest the tendency to li#uify. $t even greater intensities the molten metalmay gasify. These tendencies are as emergent as the shape of a %nife2sblade a single metallic atom cannot be said to be solid, li#uid, or gas6 weneed a large enough population of interacting atoms for the tendency to be inany of these states to emerge. Tendencies are similar to capacities in theirontological status, that is, they need not be actual to be real, and when theydo become actual is as events to melt or to solidify. The main dierencebetween tendencies and capacities is that while the former are typically nitethe latter need not be. "e can enumerate, for example, the possible states inwhich a material entity will tend to be solid, li#uid, gas, plasma- or thepossible ways in which it may tend to &ow uniformly, periodically,turbulently-. !ut capacities to aect need not be nite because they dependon the capacities to be aected of innumerable other entities a %nife has thecapacity to cut when it interacts with something that has the capacity to becut6 but it also has the capacity to %ill if it interacts with large organisms withdierentiated organs, that is, with entities that have the capacity to be %illed.7ince neither tendencies nor capacities must be actual to be real it would betempting to give them the status of possibilities. !ut the concept of apossible event is philosophically suspect because it is almostindistinguishable from that of a real event, the only dierence being theformer2s lac% of reality. 8ather, what is needed is a way of specifying thestructure of the space of possibilities that is dened by an entity2s tendenciesand capacities. $ philosopher2s ontological commitment should be to theobjective existence of this structure and not to the possibilities themselvessince the latter exist only when entertained by a mind. 7ome possibilityspaces are continuous having a well dened spatial structure that can beinvestigated mathematically, while others are discrete, possessing noinherent spatial order but being nevertheless capable of being studiedthrough the imposition of a certain arrangement. The space of possibleregimes of &ow uniform, periodic, turbulent- is an example of a continuous


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possibility space in which the only discontinuities are the critical pointsseparating the dierent tendencies. The space of possible genes, on theother hand, is an example of a discrete space that must be studied byimposing an order on it, such as an arrangement in which every gene has asneighbors other genes diering from it by a single mutation. $s we will see inthe dierent chapters of this boo% the structure of possibility spaces plays as

great a role in the explanation of emergence as do mechanisms.The chapters are deliberately arranged in a way that departs from the ideasof the original emergentists. These philosophers believed that entities li%e'7pace+Time(, '/ife(, '0ind(, and '1eity( not 'god( but the sense of thesacred that emerges in some minds- formed a pyramid of progressivelyascending grades. $lthough the levels of this pyramid were not supposed toimply any teleology it is hard not to view each level as leading to the nextfollowing a necessary se#uence. To eliminate this possible interpretation anentirely dierent image is used here, that of a contingent accumulation oflayers or strata that may dier in complexity but that coexist and interactwith each other in no particular order a biological entity may interact with asubatomic one, as when neurons manipulate concentrations of metallic ions,

or a psychological entity interact with a chemical one, as when subjectiveexperience is modied by a drug. The boo% begins with purely physicalentities, thunderstorms, that are already complex enough to avoid the ideathat their behavior can be deduced from a general law. It then moves on toexplore the prebiotic soup, bacterial ecosystems, insect intelligence,mammalian memory, primate social strategies, and the emergence of trade,language, and institutional organi9ations in human communities. Each ofthese layers will be discussed in terms of the mechanisms of emergenceinvolved, drawing ideas and insights from the relevant elds of science, aswell as in terms of the structure of their possibility spaces, using the resultsof both mathematical analysis and the outcomes of computer simulations.7imulations are partly responsible for the restoration of the legitimacy of theconcept of emergence because they can stage interactions between virtualentities from which properties, tendencies, and capacities actually emerge.7ince this emergence is reproducible in many computers it can be probed andstudied by dierent scientists as if it were a laboratory phenomenon. In otherwords, simulations can play the role of laboratory experiments in the study ofemergence complementing the role of mathematics in deciphering thestructure of possibility spaces. $nd philosophy can be the mechanismthrough which these insights can be synthesi9ed into an emergent materialistworld view that nally does justice to the creative powers of matter andenergy.MANUEL DELANDA

:5ote The following essay is the Introduction to a new boo% by 0anuel1e/anda, easily the most important philosopher of the present day,concerning topics and concepts of particular relevance, I believe, forcontemporary and future architects. It is considerably longer than my usualposts, but the clarity of 1e/anda2s writing ma%es it a compelling read. It ispublished here under rights of 3air ;se in international copyrights law,meaning for educational and research purposes only. The boo%, entitled


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Philosophy and Simulation Th! Em!"#!n$! o% Synth!ti$ R!ason, willbe published by ?@@. /"A

Emergence in History

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