Ontological individualism holds the fairly humdrum view that the social world is entirely constituted by the activities, thoughts, and social relationships of individual actors. This short presentation provides one way of thinking about how to think about higher-level social entities from an actor-centered point of view. It provides a “mental map” for social entities such as organizations, institutions, ideologies, cultures, power, and social structures, within the overall framework of an actor-centered social ontology. The video spells out some of the implications of the idea of “methodological localism” developed elsewhere in the blog (link, link, link, link).
Here is a brief summary of the idea of methodological localism:
I offer a social ontology that I refer to as methodological localism (ML). This theory of social entities affirms that there are large social structures and facts that influence social outcomes. But it insists that these structures are only possible insofar as they are embodied in the actions and states of socially constructed individuals. The “molecule” of all social life is the socially constructed and socially situated individual, who lives, acts, and develops within a set of local social relationships, institutions, norms, and rules. (link)
The presentation sketches a view of how to think about higher-level features of social life — institutions, organizations, ideologies, normative frameworks, systems of power, and large-scale social structures. Each of these aspects of the social world is recognized as “real”; but it is emphasized that we need to understand the workings of these “higher-level” social entities in terms of the beliefs, ideas, and situations of the individual actors who play roles within them. Institutions are indeed a kind of mutually supporting “house of cards” (in James Coleman’s phrase; link), in which the causal power of institutions to shape and motivate future individuals depends upon the corresponding features of agency and motivation possessed by current individuals.
This simple ontology implies a broad orientation for research in sociology: to uncover the concrete and specific characteristics of social arrangements at all levels. This includes such things as the specifics of the arrangements through which individuals acquire their ways of thinking and acting in the world, and the arrangements that constitute the fields of incentives, opportunities, rules, and resources through which they live their lives. Turning attention to the higher-level “assemblages” of actors (organizations, institutions, ideologies, normative frameworks, systems of power), the actor-centered approach requires that we pay attention to the ways in which high-level causal powers disaggregate across networks and systems of socially related individual actors.
Social entities and structures have properties that exercise causal influence over all of us, and over the continuing development of the society in which we live. Schools, corporations, armies, terror networks, transport networks, markets, churches, and cities all fall in this range — they are social compounds or entities that shape the behavior of the individuals who live and work within them, and they have substantial effects on the broader society as well.
So it is unsurprising that sociologists and ordinary observers alike refer to social structures, organizations, and practices as real components of the social world. Social entities have properties that make a difference, at the individual level and at the social and historical level. Individuals are influenced by the rules and practices of the organizations that employ them; and political movements are influenced by the competition that exists among various religious organizations. Putting the point simply, social entities have real causal properties that influence daily life and the course of history.
What is less clear in the social sciences, and in the areas of philosophy that take an interest in such things, is where those causal properties come from. We know from physics that the causal properties of metallic silver derive from the quantum-level properties of the atoms that make it up. Is something parallel to this true in the social realm as well? Do the causal properties of a corporation derive from the properties of the individual human beings who make it up? Are social properties reducible to individual-level facts?
John Stuart Mill was an early advocate for methodological individualism. In 1843 he wrote his System of Logic: Ratiocinative and Inductive, which contained his view of the relationships that exist between the social world and the world of individual thought and action:
All phenomena of society are phenomena of human nature, generated by the action of outward circumstances upon masses of human beings; and if, therefore, the phenomena of human thought, feeling, and action are subject to fixed laws, the phenomena of society can not but conform to fixed laws. (Book VI, chap. VI, sect. 2)
With this position he set the stage for much of the thinking in social science disciplines like economics and political science, with the philosophical theory of methodological individualism.
About sixty years later Emile Durkheim took the opposite view. He believed that social properties were autonomous with respect to the individuals that underlie them. In 1901 he wrote in the preface to the second edition of Rules of Sociological Method:
Whenever certain elements combine and thereby produce, by the fact of their combination, new phenomena, it is plain that these new phenomena reside not in the original elements but in the totality formed by their union. The living cell contains nothing but mineral particles, as society contains nothing but individuals. Yet it is patently impossible for the phenomena characteristic of life to reside in the atoms of hydrogen, oxygen, carbon, and nitrogen…. Let us apply this principle to sociology. If, as we may say, this synthesis constituting every society yields new phenomena, differing from those which take place in individual consciousness, we must, indeed, admit that these facts reside exclusively in the very society itself which produces them, and not in its parts, i.e., its members…. These new phenomena cannot be reduced to their elements. (preface to the 2nd edition)
These ideas provided the basis for what we can call “methodological holism”.
So the issue between Mill and Durkheim is the question of whether the properties of the higher-level social entity can be derived from the properties of the individuals who make up that entity. Mill believed yes, and Durkheim believed no.
This debate persists to the current day, and the positions are both more developed, more nuanced, and more directly relevant to social-science research. Consider first what we might call “generativist social-science modeling”. This approach holds that methodological individualism is obviously true, and the central task for the social sciences is to actually perform the reduction of social properties to the actions of individuals by providing computational models that reproduce the social property based on a model of the interacting individuals. These models are called “agent-based models” (ABM). Computational social scientist Joshua Epstein is a recognized leader in this field, and his book Growing Artificial Societies: Social Science From the Bottom Up provides developed examples of ABMs designed to explain well-known social phenomena from the disappearance of the Anasazi in the American Southwest to the occurrence of social unrest. Here is his summary statement of the approach:
To the generativist, explaining macroscopic social regularities, such as norms, spatial patterns, contagion dynamics, or institutions requires that one answer the following question: How could the autonomous local interactions of heterogeneous boundedly rational agents generate the given regularity?Accordingly, to explain macroscopic social patterns, we generate—or “grow”—them in agent models.
Epstein’s memorable aphorism summarizes the field — “If you didn’t grow it, you didn’t explain its emergence.” A very clear early example of this approach is an agent-based simulation of residential segregation provided by Thomas Schelling in “Dynamic Models of Segregation” (Journal of Mathematical Sociology, 1971; link). The model shows that simple assumptions about the neighborhood-composition preferences of individuals of two groups, combined with the fact that individuals can freely move to locations that satisfy their preferences, leads almost invariably to strongly segregated urban areas.
There is a surface plausibility to the generativist approach, but close inspection of many of these simulations lays bare some important deficiencies. In particular, a social simulation necessarily abstracts mercilessly from the complexities of both the social environment and the dynamics of individual action. It is difficult to represent the workings of higher-level social entities within an agent-based model — for example, organizations and social practices. And ABMs are not well designed for the task of representing dynamic social features that other researchers on social action take to be fundamental — for example, the quality of leadership, the content of political messages, or the high degree of path dependence that most real instances of political mobilization reflect.
So if methodological individualism is a poor guide to social research, what is the alternative? The strongest opposition to generativism and reductionism is the view that social properties are “emergent”. This means that social ensembles sometimes possess properties that cannot be explained by or reduced to the properties and actions of the participants. For example, it is sometimes thought that a political movement (e.g. Egyptian activism in Tahrir Square in 2011) possessed characteristics that were different in kind from the properties of the individuals and activists who made it up.
There are a few research communities currently advocating for a strong concept of emergence. One is the field of critical realism, a philosophy of science developed by Roy Bhaskar in A Realist Theory of Science (1975) and The Possibility of Naturalism (1979). According to Bhaskar, we need to investigate the social world by looking for the real (though usually unobservable) mechanisms that give rise to social stability and change. Bhaskar is anti-reductionist, and he maintains that social entities have properties that are different in kind from the properties of individuals. In particular, he believes that the social mechanisms that generate the social world are themselves created by the autonomous causal powers of social entities and structures. So attempting to reduce a process of social change to the actions of the individuals who make it up is a useless exercise; these individuals are themselves influenced by the autonomous causal powers of larger social forces.
Another important current line of thought that defends the idea of emergence is the theory of assemblage, drawn from Gilles Deleuze but substantially developed by Manuel DeLanda in A New Philosophy of Society: Assemblage Theory and Social Complexity (2006) and Assemblage Theory (2016). This theory argues for a very different way of conceptualizing the social world. This approach proposes that we should understand complex social entities as a compound of heterogeneous and independent lesser entities, structures, and practices. Social entities do not have “essences”. Instead, they are continent and heterogenous ensembles of parts that have been brought together in contingent ways. But crucially, DeLanda maintains that assemblages too have emergent properties that do not derive directly from the properties of the parts. A city has properties that cannot be explained in terms of the properties of its parts. So assemblage theory too is anti-reductionist.
The claim of emergence too has a superficial appeal. It is clear, for one thing, that social entities have effects that are autonomous with respect to the particular individuals who compose them. And it is clear as well that there are social properties that have no counterpart at the individual level (for example, social cohesion). So there is a weak sense in which it is possible to accept a concept of emergence. However, that weak sense does not rule out either generativity or reduction in principle. It is possible to hold both generativity and weak emergence consistently. And the stronger sense — that emergent properties are unrelated to and underivable from lower level properties — seems flatly irrational. What could strongly emergent properties depend on, if not the individuals and social relations that make up these higher-level social entities?
For this reason it is reasonable for social scientists to question both generativity and strong emergence. We are better off avoiding the strong claims of both generativity and emergence, in favor of a more modest social theory. Instead, it is reasonable to advocate for the idea of the relative explanatory autonomy of social properties. This position comes down to a number of related ideas. Social properties are ultimately fixed by the actions and thoughts of socially constituted individuals. Social properties are stable enough to admit of direct investigation. Social properties are relatively autonomous with respect to the specific individuals who occupy positions within these structures. And there is no compulsion to perform reductions of social properties through ABMs or any other kind of derivation. (These are ideas that were first advocated in 1974 by Jerry Fodor in “Special sciences: Or: The disunity of science as a working hypothesis” (link).)
It is interesting to note that a new field of social science, complexity studies, has relevance to both ends of this dichotomy. Joshua Epstein himself is a complexity theorist, dedicated to discovering mathematical methods for understanding complex systems. Other complexity scientists like John Miller and Scott Page are open to the idea of weak emergence in Complex Adaptive Systems: An Introduction to Computational Models of Social Life. Here is how Miller and Page address the idea of emergence in CAS:
The usual notion put forth underlying emergence is that individual, localized behavior aggregates into global behavior that is, in some sense, disconnected from its origins. Such a disconnection implies that, within limits, the details of the local behavior do not matter to the aggregate outcome. (CAS, p. 44)
Herbert Simon is another key contributor to modern complexity studies. Simon believed that complex systems have properties that are irreducible to the properties of their components for pragmatic reasons, including especially computational intractability. It is therefore reasonable, in his estimation, to look at higher-level social properties as being emergent — even though we believe in principle that these properties are ultimately determined by the properties of the components. Here is his treatment in the third edition of The Sciences of the Artificial – 3rd Edition (1996):
[This amounts to] reductionism in principle even though it is not easy (often not even computationally feasible) to infer rigorously the properties of the whole from knowledge of the properties of the parts. In this pragmatic way, we can build nearly independent theories for each successive level of complexity, but at the same time, build bridging theories that show how each higher level can be accounted for in terms of the elements and relations of the next level down. (172)
The debate over generativity and emergence may seem like an arcane issue that is of interest only to philosophers and the most theoretical of social scientists. But in fact, disputes like this one have real consequences for the conduct of an area of scientific research. Suppose we are interested in the sociology of hate-based social movements. If we begin with the framework of reductionism and generativism, we may be led to focus on the social psychology of adherents and the aggregative processes through which potential followers are recruited into a hate-based movement. If, on the other hand, we believe that social structures and practices have relatively autonomous causal properties, then we will be led to consider the empirical specifics of the workings of organizations like White Citizens Councils, legal structures like the laws that govern hate-based political expressions in Germany and France, and the ways that the Internet may influence the spread of hate-based values and activism. In each of these cases the empirical research is directed in important measure to the concrete workings of the higher-level social institutions that are hypothesized to influence the emergence and shape of hate-based movements. In other words, the sociological research that we conduct is guided in part by the assumptions we make about social ontology and the composition of the social world.
I am currently thinking about the topic of “organizational actors”, and Margaret Gilbert’s arguments about social actors are plainly relevant to this topic. It seems worthwhile therefore to reproduce a review I wrote of Gilbert’s book On Social Facts (1989) in 1993. It is a tribute to the power of Gilbert’s ideas that the book has much of the same power thirty years later that it had when it was first published. I also find it interesting that the concerns I had in the 1990s about “collective actors” and “plural subjects” expressed in this review have continued in my thinking about the social world through the current date. I continue to believe that constructs like collective actors require microfoundations that establish how they work at the level of individual “socially constituted, socially situated” individual human beings. I refer to this view as “methodological localism”; link.
I also find it interesting that my own views about social action derive, not from philosophy, but from immersion in the literatures of contentious politics and the concrete pathways through which individuals are led to mobilization and collective action. Unlike the methodological individualism associated with rational choice theory and neoclassical economics, and unlike the social holism that all too often derives from purely philosophical considerations, this literature emphasizes the actions and thoughts of individuals without making narrow and singe-dimensional assumptions about the nature of practical rationality. I learned through my study of the millenarian rebellions of late Imperial China that rebels had many motivations and many reasons for mobilization, and that good historical research is needed to disentangle the organizations, actors, and stresses that led to mobilization and rebellion in a particular region of China. The participants in the Eight Trigrams Rebellion or the Nian Rebellion in North China were not a plural subject. (For exposition of these ideas see chapter five of my Understanding Peasant China: Case Studies in the Philosophy of Social Science (1989), “Theories of peasant rebellion”.) I have included an excerpt from that chapter on the topic of collective action at the end of this post because it illustrates an “actor-centered” approach to collective action. It presents a clear counter-perspective to Gilbert’s views of “plural subjects”.
Readers may also be interested in a post written in 2009 on the topic of “Acting as a Group” (link).
Margaret Gilbert’s On Social Facts is an intelligent, closely argued and extensively analyzed treatment of the problem of social collectivity. What is a social group? What distinguishes a group from a random set of individuals—e.g. the set consisting of W. V. O. Quine, Madonna, and Napoleon? Is a social class—e.g. the English working class in the 1880s—a social group? Gilbert’s primary contention is that the notion of a collectivity—individuals constituting a group—is the central feature of social ontology and the chief focus of empirical social science. And she maintains that this concept can best be analyzed by the idea of a “plural subject”—the referent of the first-person plural pronoun, “we”.
The core of Gilbert’s theory of social groups involves the idea of the mutual recognition by a set of persons that they are engaged in some joint actions or beliefs. “A set of people constitute a social group if and only if they constitute a plural subject”; and a plural subject is “a set of people each of whom shares with oneself in some action, belief, attitude, or similar attribute” (p. 204). Gilbert argues that the pronouns “us” and “we” are the linguistic elements through which we refer to plural subjects in English. And she believes that plural subjects exist; they are not fictions or constructions, but agents which have beliefs, perform actions, and succeed or fail in carrying out their intentions. In later chapters Gilbert extends her conception of collectivities and plural subjects by considering several other important social notions: the idea of a social fact in Durkheim’s sense, the idea of a collective belief, and the idea of a social convention. In each case Gilbert argues that the concept of a plural subject supports a plausible and intuitively convincing analysis of the social concept in question. According to Gilbert, “social groups are plural subjects, collective beliefs are the beliefs of plural subjects, and social conventions are the ‘fiats’ of plural subjects” (p. 408). Gilbert’s account of social conventions is developed through extensive discussion of David Lewis’s influential formulation of this concept.
Gilbert argues against the individualism of Max Weber (and by implication, the premises of rational choice theory), by arguing that collectivities are the central subject of the social sciences, and that collectivities cannot be subsumed under (narrowly) individualist concepts. Thus Gilbert suggests that her theory offers support for holism over individualism (p. 3). Does it? I think not. An individualist is free to acknowledge that individuals have beliefs that refer to other persons and groups of persons; the position permits reference to shared purposes and actions involving a collection of persons deliberately orienting their actions towards a shared purpose. What individualism requires is simply that these are all the aggregate results of individual states of mind, and that the behavior of the ensemble is to be explained by reference to the beliefs and intentions of the participants.
An important test case for Gilbert’s account is the problem of collective action. Rational choice theory places much emphasis on public goods problems and the phenomenon of free-riding. How does Gilbert’s conception of plural subjects treat the problem? It appears to this reader that Gilbert makes collective action too easy. Plural subjects (groups) have purposes; individuals within these groups express quasi-readiness to perform their part of the shared action; and—when circumstances are right—the group acts collectively to bring about its collective goals. “The people concerned would be jointly ready jointly to perform a certain action in certain circumstances” (p. 409). She speaks of group will or communal will (p. 410). But the actions of a group are still the result of the choices made by constituent individuals. And however much the individual may align him- or herself with the collective project, the collective behavior is still no more than the sum of the actions taken by particular individuals. Moreover, it is necessary to acknowledge the endurance of private, individual interests that remain prominent for individual agents—with the result that we should expect individuals’ actions to sometimes involve free-riding, defection, and favoring of private over collective interests. It seems to this reader, then, that Gilbert leans too far in the direction of the Rousseauvian “general will” interpretation of social action.
How important for the social sciences is the notion of a social group or collectivity? Gilbert’s view is that this concept is foundational; it is the basis for a unitary definition of the subject matter of the social sciences. This overstates the importance of collectivities, it seems to this reader: there are important instances of social explanation that do not involve analysis of groups in Gilbert’s sense, and whose explanatory frameworks do not refer to groups, their behavior, their shared beliefs, or their collective intentions and self-understandings. A few examples might include neo-malthusian analysis of the relation between economic change and demographic variables; analysis of the effects of changes of the transport system on patterns of settlement and economic activity; and explanation of patterns of historical processes of urbanization in terms of changing economic and political institutions. These examples explain social phenomena as the aggregate result of large numbers of rational individual actions. They commonly refer to impersonal social structures and circumstances that function as constraints and opportunities for individuals. And they make no inherent reference to the forms of group collectivity to which Gilbert refers.
This is a rich book, and one that repays careful reading. It will be of particular interest to philosophers of social science and social philosophers, and the level of philosophical rigor will interest philosophers in other fields as well.
Here is a relevant excerpt from Understanding Peasant China, published in the same year as On Social Facts, on collective action as the composition of individual actors who are mobilized around a shared set of goals.
Rebellion is an example of collective action; but this concept requires some analysis, for not all forms of mass behavior constitute collective action. A collective action involves at least the idea of a collective goal (that is, a goal which participants in the event share as the aim of their actions), and it suggests some degree of coordination among individuals in pursuit of that goal. Thus a mass demonstration against the government is a collective action, whereas the panicked retreat through the streets after troops have dispersed the demonstration is not. Both are forms of mass behavior, but only the demonstration has the features of collective intentionality and coordination that would constitute a collective action. We may define a collective action, then, as the aggregation of a number of individuals performing intentional, coordinated actions that are intended to help attain some shared goal or purpose. This account distinguishes collective action from other forms of mass behavior in which the individuals do not intend to contribute to a group effect—for example, a panicked stampede in a football stadium, a run on a bank, or a cycle of hoarding food during a famine. Collective actions can be classified according to the kind of shared goals that guide the individuals who participate in them—private interests and group interests. In some cases a collective action is inspired by the immediate gains available to each participant through coordinated action; in others, the action is inspired by the shared belief that the action will lead to an outcome that will benefit the group. An example of a collective action motivated by private interest would be a coordinated attack on a granary during a famine. No individual family has the strength to attack the granary by itself, but through coordinated efforts a group of fifty families may succeed. Each participant has the same goal—to acquire grain for subsistence—but the participants’ aims are private. By contrast, a demonstration by Polish workers in support of the Solidarity movement would appear to be motivated by a perception of group interest—in this case, the interest that Polish workers have as a group in representation by an independent labor union. … As we have seen in other contexts, the prospect of collective action raises the possibility of free riding: if the benefits of collective action are indivisible and undeniable to nonparticipants, it would be rational for the self-interested individual to not participate. To the extent that the potential benefits of a collective action are public rather than private, and to the extent that the action is designed to produce distant rather than immediate benefits, collective action theory predicts that it will be difficult to motivate rational individuals in support of the action. Another important factor in the success or failure of collective action, besides the character and timing of benefits to members, is the idea of assurance: potential contributors’ confidence in the probability of success of the joint enterprise. As Elster, Hardin, and others show, the level of assurance is critical to the decisions of potential contributors. If success is widely believed to be unlikely, potential contributors will be deterred from joining the collective action. An important dimension of assurance is the likelihood that other potential contributors will act. Each must judge the probability that enough people will support the action and so make success more likely. One central task of leadership and organization is to bolster the assurance of each member of the group in the likely support of other members. (UPC 147-149)
Supervenience is the view that the properties of some composite entity B are wholly fixed by the properties and relations of the items A of which it is composed (link, link). The transparency of glass supervenes upon the properties of the atoms of silicon and oxygen of which it is composed and their arrangement.
Can the same be said of a business firm like Xerox when we consider its constituents to be its employees, stakeholders, and other influential actors and their relations and actions? (Call that total field of factors S.) Or is it possible that exactly these actors at exactly the same time could have manifested a corporation with different characteristics?
Let’s say the organizational properties we are interested in include internal organizational structure, innovativeness, market adaptability, and level of internal trust among employees. And S consists of the specific individuals and their properties and relations that make up the corporation at a given time. Could this same S have manifested with different properties for Xerox?
One thing is clear. If a highly similar group of individuals had been involved in the creation and development of Xerox, it is entirely possible that the organization would have been substantially different today. We could expect that contingent events and a high level of path dependency would have led to substantial differences in organization, functioning, and internal structure. So the company does not supervene upon a generic group of actors defined in terms of a certain set of beliefs, goals, and modes of decision making over the history of its founding and development. I have sometimes thought this path dependency itself if enough to refute supervenience.
But the claim of supervenience is not a temporal or diachronic claim, but instead a synchronic claim: the current features of structure, causal powers, functioning, etc., of the higher-level entity today are thought to be entirely fixed by the supervenience base (in this case, the particular individuals and their relations and actions). Putting the idea in terms of possible-world theory, there is no possible world in which exactly similar individuals in exactly similar states of relationship and action would underlie a business firm Xerox* which had properties different from the current Xerox firm.
One way in which this counterfactual might be true is if a property P of the corporation depended on the states of the agents plus something else — say, the conductivity of copper in its pure state. In the real world W copper is highly conductive, while in W* copper is not-conductive. And in W, let’s suppose, Xerox has property P rather than P. On this scenario Xerox does not supervene upon the states of the actors, since these states are identical in W and W*. This is because dependence on the conductivity of copper makes a difference not reflected in a difference in the states of the actors.
But this is a pretty hypothetical case. We would only be justified in thinking Xerox does not supervene on S if we had a credible candidate for another property that would make a difference, and I’m hard pressed to do so.
There is another possible line of response for the hardcore supervenience advocate in this case. I’ve assumed the conductivity of copper makes a difference to the corporation without making a difference for the actors. But I suppose it might be maintained that this is impossible: only the states of the actors affect the corporation, since they constitute the corporation; so the scenario I describe is impossible.
The upshot seems to be this: there is no way of resolving the question at the level of pure philosophy. The best we can do is to do concrete empirical work on the actual causal and organizational processes through which the properties of the whole are constituted through the actions and thoughts of the individuals who make it up.
But here is a deeper concern. What makes supervenience minimally plausible in the case of social entities is the insistence on synchronic dependence. But generally speaking, we are always interested in the diachronic behavior and evolution of a social entity. And here the idea of path dependence is more credible than the idea of moment-to-moment dependency on the “supervenience base”. We might say that the property of “innovativeness” displayed by the Xerox Corporation at some periods in its history supervenes moment-to-moment on the actions and thoughts of its constituent individuals; but we might also say that this fact does not explain the higher-level property of innovativeness. Instead, some set of events in the past set the corporation on a path that favored innovation; this corporate culture or climate influenced the selection and behavior of the individuals who make it up; and the day-to-day behavior reflects both the path-dependent history of its higher-level properties and the current configuration of its parts.
(Thanks, Raphael van Riel, for your warm welcome to the Institute of Philosophy at the University of Duisburg-Essen, and for the many stimulating conversations we had on the topics of supervenience, generativity, and functionalism.)
I’ve argued for the idea that social phenomena are generated by the actions, thoughts, and mental frameworks of myriad actors (link). This expresses the idea of ontological individualism. But I also believe that social arrangements — structures, ideologies, institutions — have genuine effects on the actions of individual actors and populations of actors and on intermediate-level social structures. There is real downward and lateral causation in the social world. Are these two views compatible?
I believe they are compatible.
The negative view holds that what appears to be downward causation is really just the workings of the lower-level components through their aggregation dynamics — the lower struts of Coleman’s boat (link). So when we say “the ideology of nationalism causes the rise of ultraconservative political leaders”, this is just a shorthand for “many voters share the values of nationalism and elect candidates who propose radical solutions to issues like immigration.” This seems to be the view of analytical-sociology purists.
But consider the alternative view — that higher level entities sometimes come to possess stable causal powers that influence the behavior and even the constitution of the entities of which they are composed. This seems like an implausible idea in the natural sciences — it is hard to imagine a world in which electrons have different physical properties as an effect of the lattice arrangement of atoms in a metal. But human actors are different from electrons and atoms, in that their behavior and constitution are in fact plastic to an important degree. In one social environment actors are disposed to be highly attentive to costs and benefits; in another social environment they are more amenable to conformance to locally expressed norms. And we can say quite a bit about the mechanisms of social psychology through which the cognitive and normative frameworks of actors are influenced by features of their social environments. This has an important implication: features of the higher-level social reality can change the dispositions and workings of the lower-level actors. And these changes may in turn lead to the emergence of new higher-level factors (new institutions, new normative systems, new social practices of solidarity, …). So enduring social arrangements can cause changes in the dynamic properties of the actors who live within them.
Could we even say, more radically and counter-intuitively, that a normative structure like extremist populism “generates” behavior at the individual level? So rather than holding that individual actions generate higher-level structures, might we hold that higher-level normative structures generate patterns of behavior? For example, we might say that the normative strictures of patriarchy generate patterns of domination and deference among men and women at the individual level; or the normative strictures of Jim-Crow race relations generate individual-level patterns of subordination and domination among white and black individuals. There is a sense in which this statement about the direction of generation is obviously true; broadly shared knowledge frameworks or normative commitments “generate” typical forms of behavior in stylized circumstances of choice.
Does this way of thinking about the process of “generation” suggest that we need to rethink the directionality implied by the micro-macro distinction? Might we say that normative systems and social structures are as fundamental as patterns of individual behavior?
Consider the social reality depicted in the photograph above. Here we see coordinated action of a number of soldiers climbing out of a trench in World War I to cross the killing field of no mans land. The dozen or so soldiers depicted here are part of a vast army at war (3.8 million by 1918), deployed over a front extending hundreds of miles. The majority of the soldiers depicted here are about to receive grievous or mortal wounds. And yet they go over the trench. What can we say about the cause of this collective action at a specific moment in time? First, an order was conveyed through a communications system extending from commander to sergeant to enlisted man: “attack at 7:00 am”. Second, the industrial wealth of Great Britain permitted the state the ability to equip and field a vast infantry army. Third, a system of international competition broke down into violent confrontation and war, leading numerous participant nations to organize and fund armies at war to defeat their enemies. Fourth, the morale of the troops was maintained at a sufficiently high level to avoid mass desertion and refusal to fight. Fifth, an infantry training regime existed which gave ordinary farmhands, workers, accountants, and lords the habits and skills of infantry soldiers. All of these factors are part of the causal background of this simple episode in World War I; and most of these factors exist at a meso- or macro-level of social organization. Clearly this particular group of social actors was influenced by higher-level social factors. But equally clearly, the mechanisms through which these higher-level social factors work are straightforward to identify through reference to systems of individual actors.
Think for a minute about materials science. The hardness of titanium causes the nail to scratch the glass. It is true that material properties like hardness depend upon their microstructures. Nonetheless we are perfectly comfortable in attributing real causal powers to titanium at the level of a macro-material. And this attribution is not merely a way of summarizing a long story about the micro-structure of metallic titanium.
I’ve generally tried to think about these kinds of causal stories in terms of the idea of microfoundations. The hardness of titanium derives from its microfoundations at the level of atomic and subatomic causation. And the causal powers of patriarchy derive from the fact that the normative principles of partriarchy are embedded in the minds and behavior of many individuals, who become exemplars, enforcers, and encouragers of compliant behavior. The processes through which individuals acquire normative principles and the processes through which they behaviorally reflect these principles constitute the microfoundations of the meso- and macro-power of patriarchy.
So the question of whether there is downward causation seems almost too easy. Of course there is downward causation in the social world. Individuals are influenced in their choices and behavior by structural and normative factors beyond their control. And more fundamentally, individuals are changed in their fundamental dispositions to behavior through their immersion in social arrangements.
The worrisome likelihood that Russians and other malevolent actors are tinkering with public opinion in Western Europe and the United States through social media creates various kinds of anxiety. Are our democratic values so fragile that a few thousand Facebook or Twitter memes could put us on a different plane about important questions like anti-Muslim bigotry, racism, intolerance, or fanaticism about guns? Can a butterfly in Minsk create a thunderstorm of racism in Cincinnati? Have white supremacy and British ultra-nationalism gone viral?
There is an interesting analogy here with the weather. The weather next Wednesday is the net consequence of a number of processes and variables, none of which are enormously difficult to analyze. But in their complex interactions they create outcomes that are all but impossible to forecast over a period of more than three days. And this suggests the interesting idea that perhaps public opinion is itself the result of complex and chaotic processes that give rise to striking forms of non-linear change over time.
Can we do a better job of understanding the dynamics of public opinion by making use of the tools of complexity theory? Here is a summary description of complex systems provided by John Holland in Complexity: A Very Short Introduction:
Complexity, once an ordinary noun describing objects with many interconnected parts, now designates a scientific field with many branches. A tropical rainforest provides a prime example of a complex system. The rainforest contains an almost endless variety of species—one can walk a hundred paces without seeing the same species of tree twice, and a single tree may host over a thousand distinct species of insects. The interactions between these species range from extreme generalists (‘ army’ ants will consume most anything living in their path) to extreme specialists (Darwin’s ‘comet orchid’, with a foot-long nectar tube, can only be pollinated by a particular moth with a foot-long proboscis—neither would survive without the other). Adaptation in rainforests is an ongoing, relatively rapid process, continually yielding new interactions and new species (orchids, closely studied by Darwin, are the world’s most rapidly evolving plant form). This lush, persistent variety is almost paradoxical because tropical rainforests develop on the poorest of soils—the rains quickly leach all nutrients into the nearest creek. What makes such variety possible? (1)
Let’s consider briefly how public opinion might fit into the framework of complexity theory. On the positive side, public opinion has some of the dynamic characteristics of systems that are often treated as being complex: non-linearity, inflection points, critical mass. Like a disease, a feature of public opinion can suddenly “go viral” — reproduce many times more rapidly than in previous periods. And the collective phenomenon of public opinion has a feature of “self-causation” that finds parallels in other kinds of systems — a sudden increase in the currency of a certain attitude or belief can itself accelerate the proliferation of the belief more broadly.
On the negative side, the causal inputs to public opinion dynamics do not appear to be particularly “complex” — word-of-mouth, traditional media, local influencers, and the new factor of social media networks like Twitter, Weibo, or Facebook. We might conceptualize a given individual’s opinion formation as the net result of information and influence received through these different kinds of inputs, along with some kind of internal cognitive processing. And the population’s “opinions” are no more than the sum of the opinions of the various individuals.
Most fundamentally — what are the “system” characteristics that are relevant to the dynamics of public opinion in a modern society? How does public opinion derive from a system of individuals and communication pathways?
This isn’t a particularly esoteric question. We can define public opinion at the statistical aggregate of the distribution of beliefs and attitudes throughout a population — recognizing that there is a distribution of opinion around every topic. For example, at present public opinion in the United States on the topic of President Trump is fairly negative, with a record low 35% approval rating. And the Pew Research Center finds that US public opinion sees racism as an increasingly important problem (link):
Complexity theorists like Scott Page and John Holland focus much attention on a particular subset of complex systems, complex adaptive systems (CAS). These are systems in which the agents are themselves subject to change. And significantly, public opinion in a population of human agents is precisely such a system. The agents change their opinions and attitudes as a result of interaction with other agents through the kinds of mechanisms mentioned here. If we were to model public opinion as a “pandemonium” process, then the possibility of abrupt non-linearities in a population becomes apparent. Assume a belief-transmission process in which individuals transmit beliefs to others with a volume proportional to their own adherence to the belief and the volume and number of other agents from whom they have heard the belief, and individuals adopt a belief in proportion to the number and volume of voices they hear that are espousing the belief. Contagion is no longer a linear relationship (exposure to an infected individual results in X probability of infection), but rather a non-linear process in which the previous cycle’s increase leads to amplified infection rate in the next round.
Here is a good review article of the idea of a complex system and complexity science by Ladyman, Lambert and Wiesner (link, link). Here is a careful study of the diffusion of “fake news” by bots on Twitter (link, link). (The graphic at the top is taken from this article.) And here is a Ph.D. dissertation on modeling public opinion by Emily Cody (link).
Critical realism proposes an approach to the social world that pays particular attention to objective and material features of the social realm — property relations, impersonal institutional arrangements, supra-individual social structures. Between structure and agent, CR seems most often to lean towards structures rather than consciously feeling and thinking agents. And so one might doubt whether CR has anything useful to offer when it comes to studying the subjective side of social life.
Take for example the idea of a social identity. A social identity seems inherently subjective. It is the bundle of ideas and frameworks through which one places himself or herself in the social world, the framework through which a person conceptualizes his/her relations with others, and an ensemble of the motivations and commitments that lead to important forms of social and political action. All of this sounds subjective in the technical sense — a part of the subjective and personal experience of a single individual. It is part of consciousness, not the material world.
So it is reasonable to ask whether there is anything in a social identity that is available for investigation through the lens of critical realism.
The answer, however, seems to be fairly clear. Ideas and mental frameworks have social antecedents and causal influences. Individuals take shape through concrete social development that is conducted through stable social arrangements and institutions. Consciousness has material foundations. And therefore, it is perfectly appropriate to pursue a realist materialist investigation of social consciousness. This was in fact one important focus of the Annales school of historiography.
This is particularly evident in the example of a social identity. No one is born with a Presbyterian or a Sufi religious identity. Instead, children, adolescents, and young adults acquire their religious and moral ideas through interaction with other individuals, and many of those interactions are determined by enduring social structures and institutional arrangements. So it is a valid subject of research to attempt to uncover the pathways of interaction and influence through which individuals come to have the ideas and values they currently have. This is a perfectly objective topic for social research.
But equally, the particular configuration of beliefs and values possessed by a given individual and a community of individuals is an objective fact as well, and it is amenable to empirical investigation. The research currently being done on the subcultures of right wing extremism illustrates this point precisely. It is an interesting and important fact to uncover (if it is a fact) that the ideologies and symbols of hate that seem to motivate right wing youth are commonly associated with patriarchal views of gender as well.
So ideas and identities are objective in at least two senses, and are therefore amenable to treatment from a realist perspective. They have objective social determinants that can be rigorously investigated; and they have a particular grammar and semiotics that need to be rigorously investigated as well. Both kinds of inquiry are amenable to realist interpretation: we can be realist about the mechanisms through which a given body of social beliefs and values are promulgated through a population, and we can be realist about the particular content of those belief systems themselves.
Ironically, this position seems to converge in an unexpected way with two streams of classical social theory. This approach to social consciousness resonates with some of the holistic ideas that Durkheim brought to his interpretation of religion and morality. But likewise it brings to mind Marx’s views of the determinants of social consciousness through objective material circumstances. We don’t generally think of Marx and Durkheim as having much in common. But on the topic of the material reality of ideas and their origins in material features of social life, they seem to agree.
These considerations seem to lead to a strong conclusion: critical realism can be as insightful in its treatment of objective social structures as it is in study of “subjective” features of social consciousness and identities.
Brian Epstein is adamant that the social sciences need to think very differently about the nature of the social world. In The Ant Trap: Rebuilding the Foundations of the Social Sciences he sets out to blow up our conventional thinking about the relation between individuals and social facts. In particular, he is fundamentally skeptical about any conception of the social world that depends on the idea of ontological individualism, directly or indirectly. Here is the plainest statement of his view:
When we look more closely at the social world, however, this analogy [of composition of wholes out of independent parts] falls apart. We often think of social facts as depending on people, as being created by people, as the actions of people. We think of them as products of the mental processes, intentions, beliefs, habits, and practices of individual people. But none of this is quite right. Research programs in the social sciences are built on a shaky understanding of the most fundamental question of all: What are the social sciences about? Or, more specifically: What are social facts, social objects, and social phenomena—these things that the social sciences aim to model and explain?
My aim in this book is to take a first step in challenging what has come to be the settled view on these questions. That is, to demonstrate that philosophers and social scientists have an overly anthropocentric picture of the social world. How the social world is built is not a mystery, not magical or inscrutable or beyond us. But it turns out to be not nearly as people-centered as is widely assumed. (p. 7)
Here is one key example Epstein provides to give intuitive grasp of the anti-reductionist metaphysics he has in mind — the relationship between “the Supreme Court” and the nine individuals who make it up.
One of the examples I will be discussing in some detail is the United States Supreme Court. It is small— nine members— and very familiar, so there are lots of facts about it we can easily consider. Even a moment’s reflection is enough to see that a great many facts about the Supreme Court depend on much more than those nine people. The powers of the Supreme Court are not determined by the nine justices, nor do the nine justices even determine who the members of the Supreme Court are. Even more basic, the very existence of the Supreme Court is not determined by those nine people. In all, knowing all kinds of things about the people that constitute the Supreme Court gives us very little information about what that group is, or about even the most basic facts about that group. (p. 10)
Epstein makes an important observation when he notes that there are two “consensus” views of the individual-level substrate of the social world, not just one. The first is garden-variety individualism: it is individuals and their properties (psychological, bodily) involved in external relations with each other that constitute the individual-level substrate of the social. In this case is reasonable to apply the supervenience relation to the relation between individuals and higher-level social facts (link).
The second view is more of a social-constructivist orientation towards individuals: individuals are constituted by their representations of themselves and others; the individual-level is inherently semiotic and relational. Epstein associates this view with Searle (50 ff.); but it seems to characterize a range of other theorists, from Geertz to Goffman and Garfinkel. Epstein refers to this approach as the “Standard Model” of social ontology. Fundamental to the Standard View is the idea of institutional facts — the rules of a game, the boundaries of a village, the persistence of a paper currency. Institutional facts are held in place by the attitudes and performances of the individuals who inhabit them; but they are not reducible to an ensemble of individual-level psychological facts. And the constructionist part of the approach is the idea that actors jointly constitute various social realities — a demonstration against the government, a celebration, or a game of bridge. And Epstein believes that supervenience fails in the constructivist ontology of the Standard View (57).
Both views are anti-dualistic (no inherent social “stuff”); but on Epstein’s approach they are ultimately incompatible with each other.
But here is the critical point: Epstein doesn’t believe that either of these views is adequate as a basis for social metaphysics. We need a new beginning in the metaphysics of the social world. Where to start this radical work? Epstein offers several new concepts to help reshape our metaphysical language about social facts — what he refers to as “grounding” and “anchoring” of social facts. “Grounding” facts for a social fact M are lower-level facts that help to constitute the truth of M. “Bob and Jane ran down Howe Street” partially grounds the fact “the mob ran down Howe Street” (M). The fact about Bob and Jane is one of the features of the world that contributes to the truth and meaning of M. “Full grounding” is a specification of all the facts needed in order to account for M. “Anchoring” facts are facts that characterize the constructivist aspect of the social world — conformance to meanings, rules, or institutional structures. An anchoring fact is one that sets the “frame” for a social fact. (An earlier post offered reflections on anchor individualism; link.)
Epstein suggests that “grounding” corresponds to classic ontological individualism, while “anchoring” corresponds to the Standard View (the constructivist view).
What I will call “anchor individualism” is a claim about how frame principles can be anchored. Ontological individualism, in contrast, is best understood as a claim about how social facts can be grounded. (100)
And he believes that a more adequate social ontology is one that incorporates both grounding and anchoring relations. “Anchoring and grounding fit together into a single model of social ontology” (82).
Here is an illustrative diagram of how the two kinds of relations work in a particular social fact (Epstein 94):
So Epstein has done what he set out to do: he has taken the metaphysics of the social world as seriously as contemporary metaphysicians do other important topics, and he has teased out a large body of difficult questions about constitution, causation, formation, grounding, and anchoring. This is a valuable and innovative contribution to the philosophy of social science.
But does this exercise add significantly to our ability to conduct social science research and theory? Do James Coleman, Sam Popkin, Jim Scott, George Steinmetz, or Chuck Tilly need to fundamentally rethink their approach to the social problems they attempted to understand in their work? Do the metaphysics of “frame”, “ground”, and “anchor” make for better social research?
My inclination is to think that this is not an advantage we can attribute to The Ant Trap. Clarity, precision, surprising conceptual formulations, yes; these are all virtues of the book. But I am not convinced that these conceptual innovations will actually make the work of explaining industrial actions, rebellious behavior, organizational failures, educational systems that fail, or the rise of hate-based extremism more effective or insightful.
In order to do good social research we do of course need to have a background ontology. But after working through The Ant Trap several times, I’m still not persuaded that we need to move beyond a fairly commonsensical set of ideas about the social world:
individuals have mental representations of the world they inhabit
institutional arrangements exist through which individuals develop, form, and act
individuals form meaningful relationships with other individuals
individuals have complicated motivations, including self-interest, commitment, emotional attachment, political passion
institutions and norms are embodied in the thoughts, actions, artifacts, and traces of individuals (grounded and anchored, in Epstein’s terms)
social causation proceeds through the substrate of individuals thinking, acting, re-acting, and engaging with other individuals
These are the assumptions that I have in mind when I refer to “actor-centered sociology” (link). This is not a sophisticated philosophical theory of social metaphysics; but it is fully adequate to grounding a realist and empirically informed effort to understand the social world around us. And nothing in The Ant Trap leads me to believe that there are fundamental conceptual impossibilities embedded in these simple, mundane individualistic ideas about the social world.
And this leads me to one other conclusion: Epstein argues the social sciences need to think fundamentally differently. But actually, I think he has shown at best that philosophers can usefully think differently — but in ways that may in the end not have a lot of impact on the way that inventive social theorists need to conceive of their work.
(The photo at the top is chosen deliberately to embody the view of the social world that I advocate: contingent, institutionally constrained, multi-layered, ordinary, subject to historical influences, constituted by indefinite numbers of independent actors, demonstrating patterns of coordination and competition. All these features are illustrated in this snapshot of life in Copenhagen — the independent individuals depicted, the traffic laws that constrain their behavior, the polite norms leading to conformance to the crossing signal, the sustained effort by municipal actors and community based organizations to encourage bicycle travel, and perhaps the lack of diversity in the crowd.)
John Holland describes some of the features of behavior of complex systems in these terms in Complexity:
self-organization into patterns, as occurs with flocks of birds or schools of fish
chaotic behaviour where small changes in initial conditions (‘ the flapping of a butterfly’s wings in Argentina’) produce large later changes (‘ a hurricane in the Caribbean’)
‘fat-tailed’ behaviour, where rare events (e.g. mass extinctions and market crashes) occur much more often than would be predicted by a normal (bell-curve) distribution
adaptive interaction, where interacting agents (as in markets or the Prisoner’s Dilemma) modify their strategies in diverse ways as experience accumulates. (p. 5)
In CAS the elements are adaptive agents, so the elements themselves change as the agents adapt. The analysis of such systems becomes much more difficult. In particular, the changing interactions between adaptive agents are not simply additive. This non-linearity rules out the direct use of PDEs in most cases (most of the well-developed parts of mathematics, including the theory of PDEs, are based on assumptions of additivity). (p. 11)
Miller and Page put the point this way:
One of the most powerful tools arising from complex systems research is a set of computational techniques that allow a much wider range of models to be explored. With these tools, any number of heterogeneous agents can interact in a dynamic environment subject to the limits of time and space. Having the ability to investigate new theoretical worlds obviously does not imply any kind of scientific necessity or validity— these must be earned by carefully considering the ability of the new models to help us understand and predict the questions that we hold most dear. (Complex Adaptive Systems, kl 199)
Much of the focus of complex systems is on how systems of interacting agents can lead to emergent phenomena. Unfortunately, emergence is one of those complex systems ideas that exists in a well-trodden, but relatively untracked, bog of discussion. The usual notion put forth underlying emergence is that individual, localized behavior aggregates into global behavior that is, in some sense, disconnected from its origins. Such a disconnection implies that, within limits, the details of the local behavior do not matter to the aggregate outcome. Clearly such notions are important when considering the decentralized systems that are key to the study of complex systems. Here we discuss emergence from both an intuitive and a theoretical perspective.
(Complex Adaptive Systems, kl 832)
As discussed previously, we have access to some useful “emergence” theorems for systems that display disorganized complexity. However, to fully understand emergence, we need to go beyond these disorganized systems with their interrelated, helter-skelter agents and begin to develop theories for those systems that entail organized complexity. Under organized complexity, the relationships among the agents are such that through various feedbacks and structural contingencies, agent variations no longer cancel one another out but, rather, become reinforcing. In such a world, we leave the realm of the Law of Large Numbers and instead embark down paths unknown. While we have ample evidence, both empirical and experimental, that under organized complexity, systems can exhibit aggregate properties that are not directly tied to agent details, a sound theoretical foothold from which to leverage this observation is only now being constructed.
(Complex Adaptive Systems, kl 987)
And here is Joshua Epstein’s description of what he calls “generative social science”:
The agent-based computational model— or artificial society— is a new scientific instrument. 1 It can powerfully advance a distinctive approach to social science, one for which the term “generative” seems appropriate. I will discuss this term more fully below, but in a strong form, the central idea is this: To the generativist, explaining the emergence2 of macroscopic societal regularities, such as norms or price equilibria, requires that one answer the following question:
The Generativist’s Question
* How could the decentralized local interactions of heterogeneous autonomous agents generate the given regularity?
The agent-based computational model is well-suited to the study of this question since the following features are characteristics. (5)
Here Epstein refers to the characteristics of heterogeneity of actors, autonomy, explicit space, local interactions, and bounded rationality. And he believes that it is both possible and mandatory to show how higher-level social characteristics emerge from the rule-governed interactions of the agents at a lower level.
There are differences across these approaches. But generally these authors bring together two rather different ideas — the curious unpredictability of even fairly small interconnected systems familiar from chaos theory, and the idea that there are simple higher level patterns that can be discovered and explained based on the turbulent behavior of the constituents. And they believe that it is possible to construct simulation models that allow us to trace out the interactions and complexities that constitute social systems.
So does complexity science create a basis for a general theory of society? And does it provide a basis for understanding the features of contingency, heterogeneity, and plasticity that I have emphasized throughout? I think these questions eventually lead to “no” on both counts.
Start with the fact of social contingency. Complexity models often give rise to remarkable and unexpected outcomes and patterns. Does this mean that complexity science demonstrates the origin of contingency in social outcomes? By no means; in fact, the opposite is true. The outcomes demonstrated by complexity models are in fact no more than computational derivations of the consequences of the premises of these models. So the surprises created by complex systems models only appear contingent; in fact they are generated by the properties of the constituents. So the surprises produced by complexity science are simulacra of contingency, not the real thing.
Second, what about heterogeneity? Does complexity science illustrate or explain the heterogeneity of social things? Not particularly. The heterogeneity of social things — organizations, value systems, technical practices — does not derive from complex system effects; it derives from the fact of individual actor interventions and contingent exogenous influences.
Finally, consider the feature of plasticity — the fact that social entities can “morph” over time into substantially different structures and functions. Does complexity theory explain the feature of social plasticity? It does not. This is simply another consequence of the substrate of the social world itself: the fact that social structures and forces are constituted by the actors that make them up. This is not a systems characteristic, but rather a reflection of the looseness of social interaction. The linkages within a social system are weak and fragile, and the resulting structures can take many forms, and are subject to change over time.
The tools of simulation and modeling that complexity theorists are in the process of developing are valuable contributions, and they need to be included in the toolbox. However, they do not constitute the basis of a complete and comprehensive methodology for understanding society. Moreover, there are important examples of social phenomena that are not at all amenable to treatment with these tools.
This leads to a fairly obvious conclusion, and one that I believe complexity theorists would accept: that complexity theories and the models they have given rise to are a valuable contribution; but they are only a partial answer to the question, how does the social world work?
In an earlier post I considered the topic of phase transitions as a possible source of emergent phenomena (link). I argued there that phase transitions are indeed interesting, but don’t raise a serious problem of strong emergence. Tarun Menon considers this issue in substantial detail in the chapter he co-authored with Craig Callender in The Oxford Handbook of Philosophy of Physics, “Turn and face the strange … ch-ch-changes: Philosophical questions raised by phase transitions” (link). Menon and Callender provide a very careful and logical account of three ways of approaching the physics of phase transitions within physics and three versions of emergence (conceptual, explanatory, ontological). The piece is technical but very interesting, with a somewhat deflating conclusion (if you are a fan of emergence):
We have found that when one clarifies concepts and digs into the details, with respect to standard textbook statistical mechanics, phase transitions are best thought of as conceptually novel, but not ontologically or explanatorily irreducible.
Menon and Callendar review three approaches to the phenomenon of phase transition offered by physics: classical thermodynamics, statistical mechanics, and renormalization group theory. Thermodynamics describes the behavior of materials (gases, liquids, and solids) at the macro level; and statistical mechanics and renormalization group theory are theories of the micro states of materials intended to allow derivation of the macro behavior of the materials from statistical properties of the micro states. They describe this relationship in these terms:
Statistical mechanics is the theory that applies probability theory to the microscopic degrees of freedom of a system in order to explain its macroscopic behavior. The tools of statistical mechanics have been extremely successful in explaining a number of thermodynamic phenomena, but it turned out to be particularly difficult to apply the theory to the study of phase transitions. (193)
Here is the mathematical definition of phase transition that they provide:
Mathematically, phase transitions are represented by nonanalyticities or singularities in a thermodynamic potential. A singularity is a point at which the potential is not infinitely differentiable, so at a phase transition some derivative of the thermo dynamic potential changes discontinuously. (191)
And they offer this definition:
(Def 1) An equilibrium phase transition is a nonanalyticity in the free energy. (194)
Here is their description of how the renormalization group theory works:
To explain the method, we return to our stalwart Ising model. Suppose we coarse grain a 2 D Ising model by replacing 3 × 3 blocks of spins with a single spin pointing in the same direction as the majority in the original block. This gives us a new Ising system with a longer distance between lattice sites, and possibly a different coupling strength. You could look at this coarse graining procedure as a transformation in the Hamiltonian describing the system. Since the Hamiltonian is characterized by the coupling strength, we can also describe the coarse graining as a transformation in the coupling parameter. Let K be the coupling strength of the original system and R be the relevant transformation. The new coupling strength is K′ = RK. This coarse graining procedure could be iterated, producing a sequence of coupling parameters, each related to the previous one by the transformation R. The transformation defines a flow on parameter space. (195)
Renormalization group theory, then, is essentially the mathematical basis of coarse-graining analysis (link).
The key difficulty that has been used to ground arguments about strong emergence of phase transitions is now apparent: there seems to be a logical disjunction between the resources of statistical mechanics and the findings of thermodynamics. In theory physicists would like to hold that statistical mechanics provides the micro-level representation of the phenomena described by thermodynamics; or in other words, that thermodynamic facts can be reduced to derivations from statistical mechanics. However, the definition of a phase transition above specifies that the phenomena display “nonanalyticities” — instantaneous and discontinuous changes of state. It is easily demonstrated that the equations used in statistical mechanics do not display nonanalyticities; change may be abrupt, but it is not discontinuous, and the equations are infinitely differentiable. So if phase transitions are points of nonanalyticity, and statistical mechanics does not admit of nonanalytic equations, then it would appear that thermodynamics is not derivable from statistical mechanics. Similar reasoning applies to renormalization group theory.
This problem was solved within statistical mechanics by admitting of infinitely many bodies within the system that is represented (or alternatively, admitting of infinitely compressed volumes of bodies); but neither of these assumptions of infinity is realistic of the material world.
So are phase transitions “emergent” phenomena in either a weak sense or a strong sense, relative to the micro-states of the material in question? The strongest sense of emergence is what Menon and Callender call ontological irreducibility.
Ontological irreducibility involves a very strong failure of reduction, and if any phenomenon deserves to be called emergent, it is one whose description is ontologically irreducible to any theory of its parts. Batterman argues that phase transitions are emergent in this sense (Batterman 2005). It is not just that we do not know of an adequate statistical mechanical account of them, we cannot construct such an account. Phase transitions, according to this view, are cases of genuine physical discontinuities. (215)
The possibility that phase transitions are ontologically emergent at the level of thermodynamics is raised by the point about the mathematical characteristics of the equations that constitute the statistical mechanics description of the micro level — the infinite differentiability of those equations. But Menon and Callender give a compelling reason for thinking this is misleading. They believe that phase transitions constitute a conceptual novelty with respect to the resources of statistical mechanics — phase transitions do not correspond to natural kinds at the level of the micro-constitution of the material. But they argue that this does not establish that the phenomena cannot be explained or derived from a micro-level description. So phase transitions are not emergent according to the explanatory or ontological understandings of that idea.
The nub of the issue comes down to how we construe the idealization of statistical mechanics that assumes that a material consists of an infinite number of elements. This is plainly untrue of any real system (gas, liquid, or solid). The fact that there are boundaries implies that important thermodynamic properties are not “extensive” with volume: twice the volume leads to twice the entropy. But the way in which the finitude of a volume of material affects its behavior is through the effects of novel behaviors at the edges of the volume. And in many instances these effects are small relative to the behavior of the whole, if the volume is large enough.
Does this fact imply that there is a great mystery about extensivity, that extensivity is truly emergent, that thermodynamics does not reduce to finite N statistical mechanics? We suggest that on any reasonably uncontentious way of defining these terms, the answer is no. We know exactly what is happening here. Just as the second law of thermodynamics is no longer strict when we go to the microlevel, neither is the concept of extensivity. (201-202)
There is an important idealization on the thermodynamic description as well — the notion that several specific kinds of changes are instantaneous or discontinuous. But this assumption can also be seen as an idealization, corresponding to a physical system that is undergoing changes at different rates under different environmental conditions. What thermodynamics describes as an instantaneous change from liquid to gas may be better understood as a rapid process of change at the molar level which can be traced through in a continuous way.
(The fact that some systems are coarse-grained has an interesting implication for this set of issues (link). The interesting implication is that while it is generally true that the micro states in such a system entail the macro states, the reverse is not true: we cannot infer from a given macro state to the exact underlying micro state. Rather, many possible micro states correspond to a given macro state.)
The conclusion they reach is worth quoting:
Phase transitions are an important instance of putatively emergent behavior. Unlike many things claimed emergent by philosophers (e.g., tables and chairs), the alleged emergence of phase transitions stems from both philosophical and scientific arguments. Here we have focused on the case for emergence built from physics. We have found that when one clarifies concepts and digs into the details, with respect to standard textbook statistical mechanics, phase transitions are best thought of as conceptually novel, but not ontologically or explanatorily irreducible. And if one goes past textbook statistical mechanics, then an argument can be made that they are not even conceptually novel. In the case of renormalization group theory, consideration of infinite systems and their singular behavior provides a central theoretical tool, but this is compatible with an explanatory reduction. Phase transitions may be “emergent” in some sense of this protean term, but not in a sense that is incompatible with the reductionist project broadly construed. (222)
Or in other words, Minon and Callender refute one of the most technically compelling interpretations of ontological emergence in physical systems. They show that the phenomena of phase transitions as described by classical thermodynamics are compatible with being reduced to the dynamics of individual elements at the micro-level, so phase transitions are not ontologically emergent.
Are these arguments relevant in any way to debates about emergence in social system dynamics? The direct relevance is limited, since these arguments depend entirely on the mathematical properties of the ways in which the micro-level of physical systems are characterized (statistical mechanics). But the more general lesson does in fact seem relevant: rather than simply postulating that certain social characteristics are ontologically emergent relative to the actors that make them up, we would be better advised to look for the local-level processes that act to bring about surprising transitions at critical points (for example, the shift in a flock of birds from random flight to a swarm in a few seconds).