Whispers from Aristotle:Whispers from Aristotle:Emergentism from Physics to Emergentism from Physics to

BiologyBiology

James BarhamJames BarhamUniversity of Notre Dame andUniversity of Notre Dame and

Institute for the Study of NatureInstitute for the Study of NatureJune 11, 2008June 11, 2008

I. What Is Meant byI. What Is Meant by“Ontological Emergence”?“Ontological Emergence”?

►Ontological emergence is the claim Ontological emergence is the claim that the universe has an objective that the universe has an objective hierarchical structure, and that some hierarchical structure, and that some higher-level phenomena have real higher-level phenomena have real existence and real properties that are existence and real properties that are (partly) causally autonomous from the (partly) causally autonomous from the lower-level physical phenomena that lower-level physical phenomena that (partly) constitute them(partly) constitute them

Two Traditional ExamplesTwo Traditional Examples

►Mind:Mind: Do minds have real existence and real Do minds have real existence and real

properties that are (partly) causally properties that are (partly) causally autonomous from brains? (“mind/body autonomous from brains? (“mind/body problem”)problem”)

►Life:Life: Do living organisms have real existence Do living organisms have real existence

and real properties that are (partly) and real properties that are (partly) causally autonomous from their material causally autonomous from their material constituents? (“life/body problem”)constituents? (“life/body problem”)

II. Why Care about Ontological II. Why Care about Ontological Emergence?Emergence?

► Isn’t it just common sense?Isn’t it just common sense? If we can see that ontological emergence If we can see that ontological emergence

mustmust be true, then why worry about it? be true, then why worry about it?

►Three reasons for caring:Three reasons for caring: PhilosophicalPhilosophical Cultural/PoliticalCultural/Political ScientificScientific

III. The Strangeness of Life, from III. The Strangeness of Life, from a Physical Point of Viewa Physical Point of View

►Let us begin by considering some of Let us begin by considering some of the basic physical characteristics of the basic physical characteristics of living systemsliving systems

A. Life Is Not Just MatterA. Life Is Not Just Matter

►Constant turnover of matterConstant turnover of matter►Dead organism is materially identical Dead organism is materially identical

to living oneto living one► It is the It is the organizationorganization of matter of matter

((material formmaterial form) that is invariant with ) that is invariant with respect to time (i.e., is respect to time (i.e., is stablestable))

B. Life Is ProcessB. Life Is Process

►Stability of material form requires a Stability of material form requires a complex processcomplex process

►For material form to be stable, the For material form to be stable, the complex process supporting it must complex process supporting it must itself be stableitself be stable

►Life is a Life is a dynamically stable complex dynamically stable complex processprocess

C. The Essence of Life Is C. The Essence of Life Is MetabolismMetabolism

►Two aspects of stability of form:Two aspects of stability of form: Metabolism (stability of individual)Metabolism (stability of individual) Reproduction (stability of type)Reproduction (stability of type)

►Logical priority of metabolismLogical priority of metabolism►Empirical priority of metabolismEmpirical priority of metabolism►Metabolism, too, is a dynamically stable Metabolism, too, is a dynamically stable

complex processcomplex process►The essence of life is metabolism The essence of life is metabolism (Boden (Boden

1999)1999)

D. The Functional Stability of D. The Functional Stability of Metabolism (Life)Metabolism (Life)

► A minimal requirement for metabolism is a A minimal requirement for metabolism is a work cyclework cycle (Kauffman 2004)(Kauffman 2004)

►Metabolism arises through the Metabolism arises through the directedness directedness of the forces on, and displacements of, of the forces on, and displacements of, matter matter towardtoward the stability of material and the stability of material and dynamical formdynamical form

►Metabolism is an essentially goal-directed, Metabolism is an essentially goal-directed, that is, that is, functionalfunctional, activity, activity

► The dynamical stability of metabolism (life) The dynamical stability of metabolism (life) is a is a functional stabilityfunctional stability

E. Life Is Not Pure Process, E. Life Is Not Pure Process, EitherEither

►The phenomenon of The phenomenon of cryptobiosiscryptobiosis (Clegg (Clegg

2001) 2001) shows that life is not just pure, shows that life is not just pure, ongoing processongoing process

►Capacity for life is Capacity for life is inherentinherent in a in a particular state of matter (“the living particular state of matter (“the living state”)state”)

►Vital activity is Vital activity is spontaneousspontaneous

F. Summary and Definition of F. Summary and Definition of LifeLife

► Life is a dynamically stable complex processLife is a dynamically stable complex process► Life does work directed toward the stability Life does work directed toward the stability

of its own material and dynamical formof its own material and dynamical form► The stability of life is functional stabilityThe stability of life is functional stability► Life is a capacity for spontaneous activity Life is a capacity for spontaneous activity

inherent in a particular kind of matterinherent in a particular kind of matter►DefinitionDefinition: : Life is the inherent capacity Life is the inherent capacity

of a particular kind of material system of a particular kind of material system for spontaneous activity resulting in for spontaneous activity resulting in the functional stability of the systemthe functional stability of the system

G. Life Is StrangeG. Life Is Strange

► Fantastic complexity of cellFantastic complexity of cell►On the order of magnitude of tens of On the order of magnitude of tens of

thousands of different thousands of different typestypes of of macromolecules, with as many as a million macromolecules, with as many as a million exemplars of some types at a given time—exemplars of some types at a given time—all tightly functionally choreographed all tightly functionally choreographed Life defies the spirit of the 2Life defies the spirit of the 2ndnd Law of Law of

Thermodynamics (though not the letter)Thermodynamics (though not the letter)

► The very concept of function is utterly The very concept of function is utterly foreign to physics and chemistryforeign to physics and chemistry

H. Two Problems: Origin and H. Two Problems: Origin and StabilityStability

►Origin of life is not the only problemOrigin of life is not the only problem►Functional stability of life is also an Functional stability of life is also an

important problemimportant problem►Emergentism is important because it Emergentism is important because it

may throw light on may throw light on bothboth problems problems

IV. Some Basic DistinctionsIV. Some Basic Distinctions

►To help us get a fix on some of the To help us get a fix on some of the issues involved in the claims of issues involved in the claims of emergentismemergentism

A. Reality and ExplanationA. Reality and Explanation

►Ontological claims have to do with what Ontological claims have to do with what exists: what is realexists: what is real

►Epistemological claims have to do with Epistemological claims have to do with the way in which we come to believe the way in which we come to believe ontological claims: how we explain ontological claims: how we explain thingsthings

►Ontological emergence is a claim about Ontological emergence is a claim about what is real, not about how we explain what is real, not about how we explain thingsthings

B. Two Senses of “Realism”B. Two Senses of “Realism”

► The ontological emergentist is realistThe ontological emergentist is realist► A realist about A realist about XX believes that believes that X X objectively objectively

existsexists► Two senses of “realism”:Two senses of “realism”:

Weak realism: Objective = intersubjective agreement Weak realism: Objective = intersubjective agreement Strong realism: Objective = independent of any Strong realism: Objective = independent of any

human observerhuman observer

►Ontological emergence requires strong realismOntological emergence requires strong realism► Functional facts are objective in strong-realist Functional facts are objective in strong-realist

sensesense

C. Two Senses of C. Two Senses of “Naturalism”“Naturalism”

►The ontological emergentist is naturalist, The ontological emergentist is naturalist, but only in a qualified sensebut only in a qualified sense

►Two senses of “naturalism”: Two senses of “naturalism”: Weak naturalism: assumes integrity of Weak naturalism: assumes integrity of

nature (contrast: supernatural)nature (contrast: supernatural) Strong naturalism: assumes primacy of Strong naturalism: assumes primacy of

physics (contrast: human, normative, physics (contrast: human, normative, teleological)teleological)

►Ontological emergence requires weak Ontological emergence requires weak naturalism, but rejects strong naturalismnaturalism, but rejects strong naturalism

D. Scientific Explanations and D. Scientific Explanations and RealityReality

►What is the ontological significance of What is the ontological significance of scientific explanations?scientific explanations?

► Three models:Three models: Elimination – what we mistakenly thought was Elimination – what we mistakenly thought was XX

is reallyis reallyYY; no such thing as ; no such thing as XX Reduction – Reduction – XX exists, but it has no properties exists, but it has no properties

other than those attributable to other than those attributable to YY; ; XX is “nothing is “nothing but” but” YY..

Emergence – Emergence – XX is (partly) constituted by is (partly) constituted byYY, but , but XX exists in its own right, with its own distinctive exists in its own right, with its own distinctive properties over and above those attributable to properties over and above those attributable to YY

E. Instability of ReductionismE. Instability of Reductionism

► If we say “If we say “XX is nothing but is nothing but YY,” what do we ,” what do we mean?mean?

► Either Either XX exists, or it doesn’t exists, or it doesn’t If it doesn’t, then reduction reduces to eliminationIf it doesn’t, then reduction reduces to elimination If it does, then reduction is hard to distinguish from If it does, then reduction is hard to distinguish from

emergenceemergence► The doctrine of reductionism seems The doctrine of reductionism seems

inherently unstableinherently unstable► Nevertheless, reductionism is considered the Nevertheless, reductionism is considered the

default positiondefault position► Burden of proof is on emergentismBurden of proof is on emergentism

F. Reasonableness of F. Reasonableness of EmergentismEmergentism

►Physics is usually considered the area Physics is usually considered the area where reduction is best demonstratedwhere reduction is best demonstrated

►Our strategy will be to show that Our strategy will be to show that emergence is the more reasonable emergence is the more reasonable doctrine, even for physics itselfdoctrine, even for physics itself

►Then, Then, a fortioria fortiori emergence will be emergence will be more reasonable for biologymore reasonable for biology

V. The Concept of Emergence in V. The Concept of Emergence in Condensed-Matter PhysicsCondensed-Matter Physics

►Elementary-particle physicists may be Elementary-particle physicists may be resolutely reductionist resolutely reductionist (Weinberg 1992),(Weinberg 1992), but the same is not true of condensed-but the same is not true of condensed-matter physicists matter physicists (Anderson 1972; Laughlin (Anderson 1972; Laughlin 2000)2000)

►Morrison Morrison (2006)(2006) gives us a good entrée gives us a good entrée into the scientific and philosophical into the scientific and philosophical issues surrounding this debateissues surrounding this debate

A. Morrison’s Two Basic A. Morrison’s Two Basic PointsPoints

►Morrison makes two basic points:Morrison makes two basic points: Claim of reduction of higher levels (e.g., Claim of reduction of higher levels (e.g.,

condensed matter) to lowest level condensed matter) to lowest level (elementary particles) is not warranted(elementary particles) is not warranted

Nevertheless, a kind of theoretical unity is Nevertheless, a kind of theoretical unity is preserved in the form of scale-preserved in the form of scale-transcendent “theoretical principles” transcendent “theoretical principles” (e.g., symmetry breaking, critical (e.g., symmetry breaking, critical phenomena, renormalization)phenomena, renormalization)

B. The Reality of Higher LevelsB. The Reality of Higher Levels

►Example of crystal lattice:Example of crystal lattice: Phonons are realPhonons are real Citation 1: Morrison 2006, p. 883Citation 1: Morrison 2006, p. 883

►ExcursusExcursus: Manipulability (“kickability”) as a : Manipulability (“kickability”) as a criterion of reality (Auyang 1995; Hacking criterion of reality (Auyang 1995; Hacking 1983)1983)

Phonons exist only at the higher levelPhonons exist only at the higher level Citation 2: Morrison 2006, p. 883Citation 2: Morrison 2006, p. 883

C. The Autonomy of Higher C. The Autonomy of Higher LevelsLevels

► The existence and properties of higher-level The existence and properties of higher-level entities (such as phonons) cannot be derived entities (such as phonons) cannot be derived from fundamental, elementary-particle theoryfrom fundamental, elementary-particle theory

► Furthermore, higher levels are stable because Furthermore, higher levels are stable because the physics at the higher level (“effective the physics at the higher level (“effective theory”) is insensitive to details of theory”) is insensitive to details of fundamental theoryfundamental theory

► Levels are “protectorates,” mainly a function Levels are “protectorates,” mainly a function of energy and scaleof energy and scale

► Levels explained by scale-transcendent Levels explained by scale-transcendent theoretical principles like symmetry breaking theoretical principles like symmetry breaking and renormalizationand renormalization

D. Isn’t This Just an D. Isn’t This Just an Epistemological Point?Epistemological Point?

► The reductionist may say: “Granted we cannot derive The reductionist may say: “Granted we cannot derive the existence of phonons from first principles in the existence of phonons from first principles in practice; but this is only due to our limited knowledge. practice; but this is only due to our limited knowledge. In theory (if we were omniscient) we could”In theory (if we were omniscient) we could”

► But ontological claims should be backed by empirical But ontological claims should be backed by empirical or theoretical warrant, and here is nothing in present-or theoretical warrant, and here is nothing in present-day scientific practice to warrant the reductionist’s in-day scientific practice to warrant the reductionist’s in-principle claimprinciple claim

► All the real science requires input of empirically All the real science requires input of empirically derived parameters (“effective theories”)derived parameters (“effective theories”)

► So, the emergentist may respond: What is the So, the emergentist may respond: What is the scientific warrant for reductionism as the default scientific warrant for reductionism as the default position?position?

E. But This Does Not Mean E. But This Does Not Mean “Disunity of Science”“Disunity of Science”

►Some anti-reductionist philosophers Some anti-reductionist philosophers espouse the “disunity of science” espouse the “disunity of science” (e.g., (e.g., DuprDupré 1993)é 1993)

►But realism requires postulate of unity But realism requires postulate of unity of nature; all explanation strives of nature; all explanation strives toward unitytoward unity

►Therefore, the disunity thesis is Therefore, the disunity thesis is inherently unsatisfying, and ought to inherently unsatisfying, and ought to be rejectedbe rejected

F. Two Senses of UnityF. Two Senses of Unity

►What is the alternative?What is the alternative?►Two sense of unity of science:Two sense of unity of science:

Reduction to fundamental levelReduction to fundamental level Integration of levelsIntegration of levels

►Thus, rejecting reductionism does not Thus, rejecting reductionism does not require embracing the disunity thesisrequire embracing the disunity thesis

G. Unity as IntegrationG. Unity as Integration

►Goal of unity of science can be Goal of unity of science can be realized by means of integration of all realized by means of integration of all levels of reality, instead of by means levels of reality, instead of by means of reductionof reduction

►Scale-transcendent theoretical Scale-transcendent theoretical principles are one of the ways in which principles are one of the ways in which levels are bound togetherlevels are bound together

►So, emergence not just a “brute fact”So, emergence not just a “brute fact”

H. But Is the Emergence of Life H. But Is the Emergence of Life Physically Plausible?Physically Plausible?

► Even if emergentism can be justified in Even if emergentism can be justified in relation to condensed-matter physics, that relation to condensed-matter physics, that still leaves us very far from being able to still leaves us very far from being able to give a satisfying emergentist account of life give a satisfying emergentist account of life or mindor mind

► All we have done is sketch out a promising All we have done is sketch out a promising metaphysical framework for understanding metaphysical framework for understanding emergence, in general; much work remains emergence, in general; much work remains to be done to understand the peculiar to be done to understand the peculiar functional stability of life, in particularfunctional stability of life, in particular

► To be continued . . .To be continued . . .

ReferencesReferences► Anderson, P.W. (1972) “More Is Different,” Anderson, P.W. (1972) “More Is Different,” ScienceScience 177177: 393–396.: 393–396.► Auyang, S.Y. (1995) Auyang, S.Y. (1995) How Is Quantum Field Theory Possible? How Is Quantum Field Theory Possible? New York: Oxford New York: Oxford

University Press.University Press.► Boden, M.A. (1999) “Is Metabolism Necessary?,” Boden, M.A. (1999) “Is Metabolism Necessary?,” British Journal for the British Journal for the

Philosophy of SciencePhilosophy of Science 5050: 231–248.: 231–248.► Clegg, James S. (2001), "Cryptobiosis—A Peculiar State of Biological Clegg, James S. (2001), "Cryptobiosis—A Peculiar State of Biological

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Press.Press.► Hacking, I. (1983) Hacking, I. (1983) Representing and InterveningRepresenting and Intervening. Cambridge: Cambridge . Cambridge: Cambridge

Universit.y Press.Universit.y Press.► Kauffman, S.A. (2004) “Autonomous Agents,” in J.D. Barrow, P.C.W. Davies, Kauffman, S.A. (2004) “Autonomous Agents,” in J.D. Barrow, P.C.W. Davies,

and C.L. Harper, Jr., eds., and C.L. Harper, Jr., eds., Science and Ultimate Reality.Science and Ultimate Reality. Cambridge: Cambridge: Cambridge University Press, pp. 654–666.Cambridge University Press, pp. 654–666.

► Laughlin, R.B., et al. (2000) “The Middle Way,” Laughlin, R.B., et al. (2000) “The Middle Way,” Proceedings of the National Proceedings of the National Academy of Sciences Academy of Sciences 9797: 32–37.: 32–37.

► Morrison, M. (2006) “Emergence, Reduction, and Theoretical Principles: Morrison, M. (2006) “Emergence, Reduction, and Theoretical Principles: Rethinking Fundamentalism,” Rethinking Fundamentalism,” Philosophy of SciencePhilosophy of Science 7373: 876–887.: 876–887.

► Weinberg, Steven (1992) Weinberg, Steven (1992) Dreams of a Final Theory.Dreams of a Final Theory. New York: Pantheon. New York: Pantheon.