The term emergence refers to the appearance of a new property in an evolving system or entity. As the system changes over time, a new property that was not present before comes to be associated with it, often through an increase in complexity. Emergent phenomena are not fully reducible (in a causal, explanatory, or ontological sense) to the lower-level phenomena from which they arise. Emergence thus represents the hypothesis that the whole story (in science, and perhaps in religion) can only be told by multiple causal stories at multiple levels.
In the religion-science discussion, uses of the term emergence fall roughly into three broad categories: (1) Scientific emergence concentrates on individual instances and patterns of emergence in the natural world. Many emergent phenomena can be categorized and analyzed in a purely scientific manner without needing to raise broader questions about their philosophical or theological significance. (2) Philosophical emergence theories look for broader patterns or similarities between emergent phenomena and attempt to formulate general criteria for classifying a phenomenon as emergent. (3) Metaphysical or theological emergence theories presuppose that the natural world is hierarchically structured and that it is a fundamental feature of reality that new emergent levels are produced in the course of cosmic history. At the metaphysical level, emergence theories attempt to describe and account for the broad pattern of emergence over time. In theological theories, the ladder of emergence is associated with the nature and action of God. Both presuppose the fundamental nature of change or development and emphasize creativity or novelty as a basic feature of ultimate reality.
Critics of emergence complain that it is either trivial, untestable, or false. Trivial because it seems obvious that, as systems increase in complexity, they will express new properties not manifest at earlier stages. Thus the critic might complain that emergence just restates the concept of complexity—and in a less clear, more obscure fashion. Untestable because how could one ever test whether there is a broad pattern of emergence in natural history? And false if emergentists are claiming that mysterious new things emerge in cosmic history that cannot be understood at all in terms of more basic levels. After all, critics complain, the success that physics has enjoyed is simply success at explaining "new things" in terms of more fundamental laws.
Some classical theists have criticized emergence theories by responding that the basic nature of the world was set by the last day of creation. Humanity may move toward or away from God, but human nature as such does not change—and certainly God does not change or emerge over time, as both Augustine of Hippo (354–430) and Thomas Aquinas (c. 1225–1274) maintained. Process thinkers have argued that emergence is not as metaphysically satisfactory as, for example, Alfred North Whitehead's (1861–1947) thought, since in place of the unified framework of actual occasions (panexperientialism), emergence offers only a confusing variety of fundamental entities arising within natural history.
Instances of emergence in the natural world
The first cases of emergence arise already in quantum mechanics. (Indeed, one could speculate that spontaneous symmetry breaking constitutes the earliest instance of emergence.) In the fractional quantum Hall effect, electrons act together in strong magnetic fields to form new types of "particles." Likewise, atomic structures and the properties of bulk matter are the emergent and relatively stable results of increasing complexity in physical systems.
Thermodynamics is inherently concerned with emergence, since it relates exchanges of heat to macroscopic phenomena such as temperature, pressure, and volume. Ilya Prigogine studied the thermodynamics of irreversible processes, developing laws for the emergence of order (anentropy) in specified systems ("order through fluctuations"). To take an example from fluid turbulence, heating a fluid from below results in the Bénard phenomenon, in which the convecting fluid spontaneously forms complex hexagonal "cells." Using similar physical principles, meteorologists study emergent patterns in the weather, which demonstrate very sensitive dependence on small changes in initial conditions (e.g., Edward Lorenz's Butterfly Effect). In such systems "matter displays its potential to be self-organizing and thereby to bring into existence new forms . . . under the constraints and with the potentialities afforded by their being incorporated into systems the properties of which, as a whole, now have to be taken into account" (Peacocke, 1986, p. 53).
The emergence of life depends on emergent properties in chemistry, such as the folding properties of proteins, which in turn are products of their underlying physical structure. Likewise, auto-catalytic (self-catalyzed) processes in chemistry play a key role in increasing complexity to the level required for life. Such processes allow for the role of feedback mechanisms, which can foster an iterative, self-correcting process that leads to the formation of new structures.
Eventually, ordered dissipative structures emerged. Life requires only that they have the potential to replicate and to incorporate environment-induced changes into their physical structure. At this point biological evolution begins, in which differential survival rates depend on reproductive success in a given environment. Emergence connotes both the unbroken chain of development backward through time and the continual emergence of new forms: bio-molecules, cells (including neurons), organelles, organs, and "autonomous agents," which Stuart Kauffman defines as systems that are able to reproduce and also able to carry out at least one thermodynamic work cycle.
Emergence may involve the evolution of new structures according to as many as six metrics:
- evolution temporally or spatially;
- evolution in the progression from simple to complex;
- evolution in levels of inner organization, feedback loops, and self-catalyzing autopoiesis (Niels Gregersen);
- evolution in increasing levels of information-processing;
- evolution in the development of "subjectivity" (e.g., perception, awareness, self-awareness, self-consciousness, spiritual intuition);
- evolution in the ladder of emergence of new properties (e.g., physiological, psychological, sociological; or physical, biological, psychological, spiritual).
Philosophical analysis and implications
Understood as a philosophical position, emergence theory is derived from the details of cosmic evolution as revealed through the various natural and social sciences. Philosophical emergence generally includes some combination of the following eight theses:
- Emergentist monism : There is one natural world composed of matter and energy (Peacocke and Clayton in Russell, 2000).
- Hierarchy : This world is hierarchically structured; more complex units are formed out of more simple parts, and they in turn become the "parts" out of which yet more complex entities are formed.
- Temporal ontology : This process of hierarchical structuring takes place over time; cosmic evolution moves from the simple to the more complex, and new structures and entities emerge in the process.
- Emergentist pluralism : The manner of the emergence of one level from another, the qualities of the emergent level, the degree to which the "lower" controls the "higher," and many other features vary depending on which instance of emergence is being studied (e.g., the biophysicist Harold Morowitz has identified at least twenty-eight different levels). Emergence should thus be viewed as a family resemblance term.
- Logical features : The various instances of emergence in natural history do tend to share certain features. For any two levels, L 1 and L 2, where L 2 emerges from L 1, (a) L 1 is prior in natural history; (b) L 2 depends on L 1, such that if the states in L 1 did not exist, the qualities in L 2 would not exist; (c) L 2 is the result of a sufficient degree of complexity in L 1; (d) one might be able to predict the emergence of some new or emergent qualities on the basis of what one knew about L 1. But one would not be able to predict the precise nature of these qualities, the rules that govern their interaction (or their phenomenological patterns), or the sorts of emergent levels that they may in due course give rise to; (e) L 2 is not reducible to L 1 in any of the standard senses of "reduction" in the philosophy of science literature (causal, explanatory, metaphysical, or ontological reduction).
- Downward causation : In some cases, phenomena at L 2 exercise a causal effect on L 1, which is not reducible to an L 1 causal history. This causal nonreducibility is not just epistemic, in the sense that humans cannot tell the L 1 causal story but an omnipotent being could. It is ontological: The world is such that it produces systems whose emergent properties exercise their own distinct causal forces among each other and on (at least) the next lower level in the hierarchy.
- Against dualism : Although the emergence of consciousness in the brain is significant to humans, it is not the defining moment of emergence. Emergence theory refers to the process of emergence as a whole, not merely to a single instance of emergence.
- Against dual aspect monism : Traditionally, as in Baruch Spinoza (1632–1677), dual aspect monism implies that there is no causal interaction between mental and physical properties, whereas emergence theories maintain that there is a dependence of the mental upon the physical and two-way causal influence between them.
Metaphysical or theological emergence
Emergentist theologies take several different forms, some focusing on emergence within the world, and some on emergence and the nature of God. Regarding the former, three forms are possible, here listed in order of increasing strength of divine involvement.
- The process of emergence might represent a basic feature of the natural world. Fundamental laws and constants and the nature of matter and energy are such that increasingly complex entities and states of affairs are formed, and more complex systems naturally give rise to new emergent properties. The emphasis is on the lawlike nature of the process: Once such basic features are set, emergence will occur naturally. It may have no broader significance outside itself.
- The same view of emergence being presupposed, a teleological dimension might be added. God established these features with the intention that the world would produce ever more complex entities and properties, such as complex biochemical molecules, living organisms, and the brains of the higher primates, as well as culture, art, philosophy, and perhaps religious understanding. In all cases, the pattern of complexification, once the preconditions are given, requires no divine intervention to be carried out.
- God might be more directly involved in bringing about emergent levels of reality. This might involve a general "lure," a constant introduction of creativity into the natural process, as argued by Whitehead and most process thinkers; it might involve the claim that in nature emergent levels (life, experience, self-consciousness) would not have occurred except for the role of God; or, the theist may assert, the entire process reflects God's providential role in history, working the divine will in to mold reality to God's image, for example, bringing about humankind in the image of God (imago Dei ) through God's constant creative or redemptive activity.
It is important to note that one can advocate an emergence theory of the natural world without maintaining any emergence within God. Thus one might hold an Augustinian view of God, such that God is completely immutable and dwells in a timeless eternal realm, yet through an act or series of acts preordained before creation God brings about its emergent history (its levels of emergence). On this view, emergence is divinely caused and entails a temporal process in the world, but it does not entail any change in God (Ernan McMullin).
Various forms of dipolar theism allow emergence within God, without asserting that "God comes into being" along with the process of emergence of the cosmos. So, for example, the essential or "antecedent" nature of God might be eternal and unchanging through the cosmic process, whereas the "consequent" nature of God—the side of God that interacts with and responds to the world—grows, develops, and even changes over the course of cosmic history. There is emergence within God at least in the sense that the divine experience becomes richer, containing experiences and responses that were not there ab initio, even though the essential nature of God remains constant.
Finally, the strongest forms of "emergentist theism" maintain that God comes to be along with the process of history. The world and the divine are inextricably wed: Where there is no world, there is no God. The world and God then come into being together, and perhaps the process will culminate in a deification of the world through this identity or association.
See also Autopoiesis; Complexity; Supervenience
holland, john. emergence: from chaos to order. reading, mass.: addison-wesley, 1998.
kauffman, stuart. investigations. new york: oxford university press, 2000.
peacocke, arthur. god and the new biology. london: dent; san francisco: harper, 1986.
peacocke, arthur. theology for a scientific age: being and becoming—natural, divine, and human. minneapolis, minn.: fortress, 1993.
prigogine, ilya. from being to becoming: time and complexity in the physical sciences. san francisco: w. h. freeman, 1980.
russell, robert john; murphy, nancey; and meyering, theo c., eds. neuroscience and the person: scientific perspectives on divine action. vatican city state: vatican observatory; berkeley, calif.: center for theology and the natural sciences, 1999.
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Emergence is, broadly speaking, the fact that there are features of the world—objects, properties, laws, perhaps other things—that are manifested as a result of the existence of other, usually more basic, entities but that cannot be completely reduced to those other entities. Theories of emergence tend to fall into two basic types: ontological emergence and epistemological emergence—with conceptual emergence serving as a subcategory of the latter. Advocates of ontological emergence consider emergent phenomena to be objective features of the world, their emergent status being independent of human existence and knowledge; advocates of epistemological emergence consider emergent features to be a result of the limited abilities of people to predict, to calculate, to observe, and to explain; and advocates of conceptual emergence consider emergent features to be a product of theoretical and linguistic representations of the world.
Emergence has considerable philosophical importance because the existence of certain kinds of ontologically emergent entities would provide direct evidence against the universal applicability of the generative atomism that has dominated Anglo-American philosophy in the last century. By generative atomism is meant the view that there exist atomic entities, be they physical, linguistic, logical, or some other kind, and all else is composed of those atoms according to rules of combination and relations of determination. The failure of various reductionist programs, especially that of physicalism, would have significant impact on this program. In addition, the various accounts of epistemological emergence pose difficulties for the long established Cartesian requirement of completely transparent access to evidential relations.
Although there is no consensus upon what counts as an emergent entity, a cluster of features tends to recur in philosophical accounts of emergence. Emergent phenomena are irreducible, they are novel, they are usually unpredictable on the basis of theory, they are often unexplainable, they frequently involve global rather than merely local properties, and an emergent entity must emerge from something. This last feature separates emergent features from those entities whose existence does not depend upon anything else, such as the objects of fundamental physics or certain abstract entities. It also allows for two distinct kinds of emergence: static or synchronic emergence within which the emergent entities exist simultaneously with the entities from which they emerge; and dynamic or diachronic emergence, within which the emergent entities temporally develop from antecedent entities. Although it is rarely stated explicitly, dynamic emergence is generally held to result from more than causal processes alone.
At one time, life and chemical compounds were considered to be good candidates for emergent features, covered by what John Stuart Mill in book III of his A System of Logic (1843, ch. VI, pts. 1–2) termed heteropathic laws, but with advances in molecular biology and an understanding of the chemical bond that view fell into disfavor. Perhaps as a consequence, emergence came to be viewed with a certain degree of suspicion, apparently requiring a commitment to occult qualities that was at odds with the analytic methods of science and philosophy. It is thus ironic that emergence has reemerged as a vigorous and lively field of investigation, has shed much of its air of mystery, and plausible candidates for emergent phenomena have been discovered in fundamental areas of physics as well as in other areas of science such as complexity theory. As a result, it is important when considering emergence not to restrict one's range of examples to the widely discussed cases of mental properties.
This entry will emphasize contemporary positions on emergence, although occasional historical references will be made to illustrate conceptual continuities. For a history of the area, the reader is referred to Brian McLaughlin's 1992 survey article, "The Rise and Fall of British Emergentism."
Ontological Approaches to Emergence
One influential ontological approach to emergence uses supervenience relations to account for emergent features. An early version of this approach by James van Cleve (1990) asserted that a property P of a system is emergent if and only if P supervenes with nomological necessity but not with logical necessity on properties of parts of the system, and some of the supervenience principles linking the basal properties with P are fundamental laws. That is, once the features of the most fundamental level are fixed, so—via laws of nature—are the features of all higher levels. Advocates of supervenience approaches, especially the widely canvassed position known as Humean supervenience, generally hold that supervenience is all that is required to account for higher-level features of the world. David Lewis provided an influential statement of this position in the second volume of his Philosophical Papers (1986, pp. ix–xvi). Supervenience approaches usually contain the irreducibility and novelty aspects of emergence. Whether the global, unpredictability, and unexplainability features are present depends upon the type of supervenience involved.
A different ontological position, developed by Jaegwon Kim in his article "Making Sense of Emergence" (1999), begins with the idea that a higher level property P is reducible if: (a) P can be functionalized—that is, defined in terms of its causal role; (b) realizers of P can be found at a lower level; and (c) there is a lower level theory that explains how the realizers operate. In contrast, a property is emergent if it is neither a physical property nor reducible to physical properties in the sense just described. Kim's position retains the irreducibility, novelty, theoretical unpredictability, and unexplainability features of emergent phenomena but apparently has the consequence that there is little scope for their existence, except perhaps in the case of qualia or consciousness.
The novelty of emergent features is usually captured in the idea that an emergent entity E must be qualitatively different from the entities from which it emerges. A popular version of this idea asserts that a property P is emergent if it has novel causal powers not possessed by entities at lower levels. The causation involved can be horizontal (to entities at the same level), upwards (to a higher level), or downwards (to a lower level). When downwards causation is involved, one of the most difficult problems facing advocates of supervenience emergence and many other ontological accounts of emergence occurs. This is the problem of causal exclusion, of explaining how emergent features can influence lower levels via downwards causation if one subscribes to the causal closure of lower levels as, for example, do most physicalists. For if the lower level is casually closed, any downwards influence is redundant, unless causal overdetermination is allowed. A clear statement of this argument can be found in Kim's 1992 article "'Downward Causation' in Emergentism and Nonreductive Physicalism."
A third ontological approach to emergence, found in Paul Humphreys' 1997 article "How Properties Emerge," addresses this problem. It has as its core idea the view that in certain cases of dynamic emergence the original elements or their properties fuse together in a way that the identities of those elements are lost in forming the new emergent entity. This feature allows emergent phenomena to avoid the causal exclusion argument because the lower level entities no longer exist and a fortiori cannot be causal competitors to the emergent entity. The position entails the irreducibility, novelty, and holistic features of emergent phenomena, but allows their predictability and explainability. Certain holistic quantum systems possessing states of joint systems but not states of individual components seem to be examples of fusion.
Epistemological Approaches to Emergence
Turning to epistemological accounts of emergence, one of the oldest approaches emphasizes the essential unpredictability of emergent phenomena. It is sometimes loosely and unhelpfully characterized in psychological terms by noting that emergent phenomena are surprising. A more precise version asserts that a property P belonging to domain E is emergent relative to a domain D, where E is at a higher level than D, if it is impossible to predict the occurrence of instances of P on the basis of any ideal theory about D. Early accounts of emergence based on unpredictability can be found in Stephen Pepper's article "Emergence" (1926) and C. D. Broad's book The Mind and Its Place in Nature (1925).
This unpredictability approach conforms to Ernest Nagel's well-known approach to the reduction of one theory to another in chapter eleven of his The Structure of Science (1961). Within Nagel's account, one theory is irreducible to another if the laws of a higher level theory cannot be deduced from those of a more fundamental theory by employing bridge laws connecting the two levels. Thus, in a somewhat crude manner the essential unpredictability approach to emergence captures the idea that if biology is Nagel-irreducible to physics then biological phenomena are emergent from physical phenomena. It satisfies the novelty, irreducibility and, trivially, unpredictability aspects of emergence and also accommodates nomological emergence, the view that entities of type B are emergent from entities of type A if and only if entities of type B have type A entities as constituents and there is at least one law that applies to type B entities that does not apply to type A entities. A statement of nomological emergence can be found in the physicist P. W. Anderson's much cited 1972 article "More Is Different."
A diachronic version of the unpredictability approach to emergence is widely used within the field of complexity theory and rests on the idea of stable patterns spontaneously emerging in a system. Although these patterns are, simply in virtue of being patterns, nonlocal, they are not the result of a central organizing principle but result from local, often nonlinear, interactions between members of a population. Examples of pattern emergence abound in what are commonly termed self-organized systems, one simple example of which is the formation and maintenance of bird flocks. The general area of agent-based or individual-based models, which include many examples of self-organizing systems, is of interest to philosophy because it combines a bottom-up commitment to individualism with the dynamic emergence of higher level structures possessing the features of novelty and holism. Such models can illuminate the traditional philosophical issue of methodological individualism, an issue that divides those who hold the view that there are sui generis facts in the social sciences from the individualists who deny this.
Because the dynamic emergence of the patterns can often be modeled only via computer simulations, an important aspect of these systems is captured by Mark Bedau's concept of weak emergence (2003). A weakly emergent property P is one possessed by a structured system S, where P is incapable of being possessed by components of S, and S's possessing P is a fact that can be derived only by a step-by-step simulation of S. Despite its connection with prediction via computer simulations, weak emergence is ultimately a metaphysical rather than an epistemological account of emergence. The structure of the system places objective constraints on the possibilities of computation and complex physical and biological systems must step through their own development, thus making weak emergence a claim about the world itself.
A particularly interesting kind of weak emergence occurs when a pattern P exists independently of the nature of the specific components of the system exhibiting the pattern so that the structure is in that sense autonomous. There are connections here with the multiple realizability of higher level properties, a topic that has played an important role in arguments against reduction. One approach to emergence that explicitly considers multiple realizability is Robert Batterman's asymptotic emergence (2002). This sort of emergence involves a relation between two theories, one of which is a limiting case of the other and it is unusual in not relying on the part/whole relationship upon which most other theories of emergence are based.
Conceptual Approaches to Emergence
Running parallel with the issues of epistemological and ontological emergence is the phenomenon of conceptual emergence, based upon the idea that theories employed at different levels of the hierarchy employ different concepts and that these concepts require the introduction of distinctive, irreducible, predicates and relations. This approach is captured in Paul Teller's characterization: An emergent property of a whole is one that is not explicitly definable in terms of the nonrelational properties of the object's proper parts (1992). Because definability depends upon the linguistic resources available in a given language or theory, this criterion for emergence is relative to the theory or language employed and reflects a common feature of linguistic development. If psychological and sociological features, to take two examples, are ontologically emergent, one should expect the resources of explicit definability to fail and to force the invention of new vocabulary. It is not difficult to see how each of the approaches to emergence described above can necessitate this kind of linguistic innovation, and it calls into question various enterprises of linguistic reduction. Although it is not couched in terms of emergence, the influential arguments found in Jerry Fodor's 1974 article "Special Sciences" against reduction and in favor of the autonomy of the special sciences can be construed as reasons in support of conceptual emergence.
In contemporary philosophy, a commitment to emergent entities is generally held to violate physicalism, the position that the world's ontology contains nothing but the ontology provided by physics. What "nothing but" means differs from one version of physicalism to another, as does what is included within the scope of physics, but the core idea is that anything not required by fundamental physics is in principle redundant, even though one may employ a nonphysicalist vocabulary for practical reasons. Thus, mental entities such as beliefs are mere façons de parler on the reductionist view, and the social sciences have no genuine subject matter of their own. Strict versions of reductionism maintain similar views about biological and chemical entities.
All three approaches to emergence—ontological, epistemological, and conceptual—tend to appeal, implicitly or explicitly, to a layered view of the world that is divided into levels, with features at higher levels emerging from those at lower levels. This appeal to levels is usually grounded in the idea that larger entities such as molecules spatially include as parts smaller constituents such as atoms, this inclusion relation resulting in the familiar hierarchy of elementary particle physics, solid state physics, chemistry, biochemistry, biology, neurophysiology, and so on. Although this levels picture serves as a natural image within synchronic emergence, it can be a seriously misleading metaphor for diachronic emergence.
There is much casual talk in the literature on emergence about the difference between aggregate features and emergent features, the latter, in contrast to the former, being more than "mere sums" of the features of their components. It has turned out not to be informative to try to precisely capture what constitutes a "mere sum" but traditionally, holism—summed up in the slogan that the whole is greater than the sum of the parts—remains a core part of what is wanted from emergent phenomena. It is preferable to replace "greater than" by "different" and if this is done one has the suggestion that a property P is emergent only if it is a property of an entire system S that is composed of subsystems S1, … Sn but none of the Si possess P. This feature is possessed by, at least, the fusion, asymptotic, weak, and nomological approaches to emergence.
The principal aim of any philosophical account of emergence should be to make emergence intelligible and nontrivial. It is a separate matter, one with which science is properly concerned, whether the universe contains any examples of emergence. It is, nevertheless, a matter of considerable interest to philosophy whether examples of ontologically emergent phenomena exist because, if they do, our universe is more than an ontologically modest combinatorial device.
Anderson, P. W. "More is Different." Science 177 (1972): 393–396.
Beckerman, Ansgar, Hans Flohr, and Jaegwon Kim, eds. Emergence or Reduction?: Essays on the Prospects of Nonreductive Physicalism. Berlin: Walter de Gruyter, 1992.
Bedau, Mark. "Downward Causation and Autonomy in Weak Emergence." Principia Revista Internacional de Epistemologica 6 (2003): 5–50.
Broad, C. D. The Mind and Its Place in Nature. London: Routledge, 1925.
Fodor, Jerry. "Special Sciences, or The Disunity of Science as a Working Hypothesis." Synthese 28 (1974): 97–115.
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Humphreys, Paul. "How Properties Emerge." Philosophy of Science 64 (1997): 1–17.
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Lewis, David. Philosophical Papers. Vol. II. Oxford: Oxford University Press, 1986.
McLaughlin, Brian. "The Rise and Fall of British Emergentism." In Emergence or Reduction?: Essays on the Prospects of Nonreductive Physicalism, edited by Ansgar Beckerman et al, 49–93. Berlin: Walter de Gruyter, 1992.
Mill, J. S. A System of Logic: Ratiocinative and Inductive. London: Longmans, Green and Company, 1843.
Nagel, Ernest. The Structure of Science. New York: Harcourt, 1961.
Pepper, Stephen. "Emergence." Journal of Philosophy 23 (1926): 241–245.
Teller, Paul. "A Contemporary Look at Emergence." In Emergence or Reduction?: Essays on the Prospects of Nonreductive Physicalism, edited by Ansgar Beckerman et al, 139–153. Berlin: Walter de Gruyter, 1992.
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"Emergence." Encyclopedia of Philosophy. . Encyclopedia.com. (February 20, 2019). https://www.encyclopedia.com/humanities/encyclopedias-almanacs-transcripts-and-maps/emergence
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