A catalogue of social mechanisms

In an earlier post I made an effort at providing the beginnings of an inventory of social mechanisms from several areas of social research. Here I’d like to go a little further with that idea in order to see how it plays into good thinking about social-science methodology.

Some Types of Social Mechanisms   CONTENTION Escalation Brokerage Diffusion Coordinated action Social appropriation Boundary activation Certification Framing Competition for power   COLLECTIVE ACTION Prisoners' dilemma Free rider behavior Convention Norms Selective benefits Selective coercion Conditional altruism Reciprocity   ORGANIZATIONAL ENFORCEMENT Audit and accounting Supervision Employee training Morale building Leadership   NORMS AND VALUES Altruistic enforcement Person-to-person transmission Imitation Subliminal transmission Erosion Charisma Stereotype threat

ECONOMIC ACTIVITY Market Auction Ministry direction Contract Market for lemons Democratic decision making Producers' control Soft budget constraint   GOVERNMENT Agenda setting Cyclical voting Log rolling Regulatory organizations Influence peddling   STATE REPRESSION Secret police files Informers Spectacular use of force Propaganda Deception Control of communications systems SOCIAL COMMUNICATIONS Interpersonal network Broadcast Rumor Transport networks SYSTEM EFFECTS Flash trading Interlocking mobilization Overlapping systems of authority (Brenner) Non-linear networks

These mechanisms have been collected from a wide range of social scientists and researchers -- Charles Tilly, Robert Axelrod, Elinor Ostrom, George Akerlof, Robert Bates, Mancur Olson, Mayer Zald, John Ferejohn, Janos Kornai, Claude Steele, and Charles Perrow, to name a few.

There are at least two kinds of questions we need to ask about a collection like this.

First, where do the entries come from? What kinds of scientific inquiry are required in order to establish that things like these are indeed mechanisms found in the social world?

The most general answer to this question concerning discovery is that much research in the various disciplines of the social sciences is specifically directed at working out the contours of mechanisms like these. Political scientists who focus on legislatures and the US Congress have become expert on identifying and validating the institutional and voting mechanisms through which legislative outcomes come to effect. Organizational sociologists study the inner workings of a range of organizations and are able to identify and validate a wide range of mechanisms at work within these organizations. Economic anthropologists and theorists study the ways in which economic transactions are conducted in a range of human settings. Social psychologists identify many of the ways that individuals acquire normative beliefs and transmit them to other individuals. The greatest difficulty in constructing a table like this is not at the level of identifying mechanisms that might be included; it is the problem of limiting the number of mechanisms identified to a more or less manageable number. There is some reason to fear that social scientists have identified thousands of mechanisms in their research, not dozens.

And second, what role does a table like this play in the conduct of research in the social sciences?

In In Search of Mechanisms: Discoveries across the Life Sciences Craver and Darden argue that biologists often approach novel phenomena with something like this table in the backs of their heads -- an inventory of known causal mechanisms in the domain of biology. From there they attempt to solve the puzzle: what combination of known mechanisms might be concatenated in order to reproduce the observed phenomenon?

Strikingly enough, this description of a heuristic for arriving at an explanatory analysis of a situation has a lot in common with the way that McAdam, Tarrow, and Tilly proceed in Dynamics of Contention. (Here is a more developed analysis of their mechanisms-based approach; link.) MT&T argue that there is a relatively manageable list of social mechanisms that can be observed in many cases of social contention. And they approach new instances with the idea that we may be able to understand the dynamics of the case by teasing out the workings of some of those mechanisms. It seems that MT&T are involved in both parts of the inquiry -- discovery and isolation of recurring mechanisms of contention, and application of these discoveries to the explanation of specific episodes of contention.

For example, they introduce their case studies in Part III of the book in these terms:

Part III of the study takes up three distinct literatures regarding contention -- revolution, nationalism, and democratization -- in view of the paths our quest has followed. The goal of that concluding section is to emphasize the commonalities as well as the differences in those forms of contention through an examination of the explanatory mechanisms and political processes we have uncovered in Parts I and II. (kl 511)

And a few paragraphs later:

Let us insist: Our aim is not to construct general models of revolution, democratization, or social movements, much less of all political contention whenever and wherever it occurs. On the contrary, we aim to identify crucial causal mechanisms that recur in a wide variety of contention, but produce different aggregate outcomes depending on the initial conditions, combinations, and sequences in which they occur. (kl 519)

Here is how they summarize their attempt to explain particular episodes of social contention. They focus on a "number of loosely connected mechanisms and processes":

• A mobilization process triggered by environmental changes and that consists of a combination of attribution of opportunities and threats, social appropriation, construction of frames, situations, identities, and innovative collective action.
• A family of mechanisms still to be elucidated around the processes of actor and identity constitution and the actions that constitute them.
• A set of mechanisms often found in trajectories of contention that recurs in protracted episodes of contention, competition, diffusion, repression, and radicalization. (kl 941)

And this body of social mechanisms is taken to provide a basis for historically grounded explanations of the forms of contention observed in specific cases.

This seems to parallel fairly closely the intellectual process that Craver and Darden describe in the case of biology: create an inventory of common causal mechanisms and analyze new cases by trying to see to what extent some of those known mechanisms can be discerned in the new material.

This account of an important type of social science research resonates well with a broad range of social science disciplines. It aligns with Robert Merton's notion of "theories of the middle range" in the social sciences, and the idea of developing a toolbox of patterns of social behavior on the basis of which to explain specific episodes. Rather than looking for general theories on the basis of which to unify wide swaths of the social world under a deductive explanatory system, this mechanisms-based approach suggests coming at social explanation piecemeal: finding the components and sub-processes of observed social ensembles, on the basis of which we can explain some aspects of the behavior of those ensembles.

We might usefully consider two additional questions. First, is there a theoretically useful way of classifying social mechanisms (formation of the individual actor, collective action, communication, repression, collective decision making, ...)? Can our catalogue provide content-relevant "chapters"? We might argue that a good taxonomy of social mechanisms actually provides a way of theorizing the main dimensions of social activity and organization. And second, are there more fundamental things we can say about how some or many of these mechanisms work? Does a good theory of the actor and a good theory of social organizations suffice to account for the workings of a great many of these mechanisms? If we respond affirmatively to this question, then once again we may have made a small degree of progress towards offering a somewhat more general theory of the social world.

Craver on mechanisms methodology

Carl Craver and Lindley Darden provide in In Search of Mechanisms: Discoveries across the Life Sciences an extensive treatment of what a mechanisms-based methodology looks like. Their work originates in study of the biological sciences, but I find that much of what they have to say is very helpful in the philosophy of social science as well.

Craver and Darden argue that the biological sciences have largely adopted a mechanisms-centered view of the nature of their science. So what is a mechanism, on their view?

Mechanisms are how things work, and in learning how things work we learn ways to do work with them. Biologists try to discover mechanisms because mechanisms are important for prediction, explanation, and control.... Mechanisms are entities and activities organized such that they are productive of regular changes from start or set-up to finish or termination conditions. (kl 581)

Fundamentally Craver and Darden  argue that a search for mechanisms is frequently a guided and constrained process, involving an attempt to match the observed activities of the system with a concatenation of known mechanism components. They want to provide a more granular account of the process of research and discovery in science, and they take issue with the idea of a flash of inspiration as the source of scientific insight. Instead, they see the process of a great deal of scientific research as one in which a methodical effort at puzzle-solving takes place, trying out different combinations of known mechanisms to see whether they may serve to explain the phenomenon in question.

In short, one often begins the search for mechanisms with a ready-made layout of the space of possible mechanisms, and the goal is to use empirical findings to eliminate regions of that space. The nature of the phenomenon and the store of accepted mechanism types thus work together to frame the discovery problem: to reveal the layout of the space of possible mechanisms and perhaps to tell one how to decide among them. (kl 1595)

They don't mean to say that there is no place for novelty or originality in scientific research; but they argue for a kind of cumulative process for much of the scientific work of discovery that builds upon the prior discovery of mechanisms and components of mechanisms.

Although occasionally biology calls upon a Darwin or a Harvey to introduce an altogether novel kind of mechanism, most episodes of mechanism discovery play out within the space of known mechanism types within a scientific field. (kl 1604)

There are many interesting and useful contributions offered in the book. One is represented in the following figure (5.1), in which Craver and Darden point out that there are multiple ways in which mechanisms are invoked in scientific research, not just one. The most common way in which we think of mechanisms is as "producers" of outcomes -- the first panel of the figure. But there are several other valid uses as well. There is the "X underlies Y" relation (panel 2), in which we provide a set of mechanisms X as an explanation of how the properties of Y are constituted; and there is the "X maintains Y" relation, in which we provide a set of mechanisms X as an explanation of the homeostasis of Y (the feedback loops and corrective mechanisms that return Y's properties to equilibrium after a period of drift or change).

 

 

Another interesting observation that C-D develop is the idea of "modular subassembly". 

This process, modular subassembly, involves reasoning about how mechanism components might be combined in surprising ways. One hypothesizes that a mechanism consists of (either known or unknown) modules or types of modules. One cobbles together different modules to construct a hypothesized how-possibly mechanism, guided by the goal of finding modules to fill all the gaps in a productively continuous mechanism. In doing so, scientists draw upon their knowledge of the store of types of entities and activities and modules (i.e., interconnected entities and activities that have a particular function). (kl 1726)

This description invokes the idea of realistic inquiry into the subprocesses that give continuous action to the mechanism. Essentially this invokes the idea of opening the black box of the mechanism and asking how the mechanism itself works. And the ontological assumption is that the mechanism consists of discrete sup-processes.

 

A third valuable idea that is advanced in this work is the idea of multi-level mechanisms. 

Biological mechanisms typically span multiple levels. Scientists working at higher levels work on ecosystems, populations, and the behaviors of organisms within their environments. Others study mechanisms within organisms, such as the nervous or circulatory systems, and mechanisms within organs and cells, and, ultimately, mechanisms with smaller entities, such as macromolecules, small molecules, and ions. Different fields of biology are often (to a first approximation) associated with different levels. (kl 688)

This is an important point for social scientists as well, given the common tendency to bifurcate into "macro" and "micro" features of the social world. Instead, C-D give further grounds for insisting that there is a wide and continuous range of levels of aggregation in the social world, and that it is perfectly legitimate to formulate representations of mechanisms that span these levels. 

 

A key feature of C-D's view of biological research is the notion that researchers make use of a wide but known stock of existing mechanisms in their efforts to understand novel phenomena. What are some of those mechanisms? Here is a very interesting table of miscellaneous biological mechanisms that Craven and Darden provide:

 

 

This table is useful exactly because it is not intended to be comprehensive or exhaustive. Rather, it is intended to provide a list of concrete mechanisms that have been observed and investigated in the biological sciences. And, as Craver and Darden argue, a large available base of known mechanisms provides a starting point for researchers who are confronting a novel phenomenon.

A collection of social mechanisms along these lines would also be valuable for researchers in the social sciences. Here is my own beginning of a table of social mechanisms:

Some Types of Social Mechanisms CONTENTION Escalation Brokerage Paramilitary organizations COLLECTIVE ACTION Prisoners' dilemma Free rider behavior Convention Norms Selective benefits Selective coercion ORGANIZATIONAL ENFORCEMENT Audit and accounting Supervision Employee training Morale building Leadership SOCIAL COMMUNICATIONS Interpersonal network Broadcast Rumor Transport networks

ECONOMIC ACTIVITY Market Auction Ministry direction Contract Democratic decision making Producers' control GOVERNMENT agenda setting Log rolling Regulatory organizations STATE REPRESSION Secret police Informers Spectacular use of force Propaganda Deception SYSTEM Flash trading Interlocking mobilization Overlapping systems of authority (Brenner)

How applicable is the Craver-Darden view of mechanism thinking when we turn to various areas of social research? There are obvious differences between the domains of biology and the social sciences, and this seems to be true when it comes to mechanisms.

One visible difference is the relative precision with which we can describe the workings of mechanisms in the two domains. The mechanism of "mismatch repair" mentioned in the C-D table under DNA Repair Mechanisms can be described in a great deal of precision, and this mechanism generally works in the same way in all settings. Compare that with the mechanism of "Audit and accounting" under Organizational Enforcement in my table above. This is also a "repair" function. But the audit function in an organization can be implemented in many different ways with varying degrees of coercion and voluntary compliance. So there is a much wider range of activities encompassed by "audit and accounting" than by "mismatch repair".

There is another kind of precision mismatch that seems to exist between biology and social science as well -- the idea that a mechanism produces the same results in a wide range of settings. Because of the molecular biology that underlies most of the mechanisms that C-D consider, these mechanisms perform like clock-work. Each tick leads to the same advancement of the wheel. But in the social world, the precision of relationship between input to a mechanism and output from the mechanism is much more slack. When a group of workers are called upon to support a wildcat strike, we may hypothesize that the free-rider mechanism will be invoked in this social setting. But free-riding may be so extensive as to cripple the strike, and it may be so limited as to barely influence the outcome at all. We can learn more about the social factors that differentiate these two outcomes. But the key point is that the mechanism is in play in both scenarios, but with very different effects.

One special strength of In Search of Mechanisms is the fact that it is a work of philosophy of science that is highly detailed in its treatment of some of the scientific content of a specific field. We cannot resolve the question of whether mechanisms are a good way of organizing scientific inquiry on the basis of apriori reasoning alone. Rather, we need to see how mechanisms-based reasoning is expressed in a range of scientific areas of inquiry. And this is exactly what Craver and Darden do in this book for a range of biological disciplines.

Ontology and methodology

Part of the dispute between analytical sociology and critical realists comes down to a complicated interplay between ontology and methodology. Both groups have strong (and conflicting) ideas about social ontology, and both think that these ideas are important to the conduct of social-science research. Analytical sociologists tend towards an enlightened version of methodological individualism: social entities derive from the actions and nature of the individuals who constitute them. Critical realists tend toward some version or another of emergentism: social entities possess properties that are emergent with respect to the individual activities that constitute them.

Both groups tend to design social science methodologies to correspond to the ontological theories that they advance. So they tacitly agree about what I regard as a questionable premise -- that ontology dictates methodology.

I want to argue for a greater degree of independence between ontology and methodology than either group would probably be willing to countenance. With the analytical sociologists I believe that social facts depend on the availability of microfoundations at the level of ensembles of individuals. This is an ontological fact. But with the critical realists I believe that it is entirely appropriate for social scientists to examine the causal and structural properties of social entities without being forced to attempt to provide the microfoundations of these properties. This is an observation about the locus and nature of explanation. There are stable structural and causal properties at the social level, and it is entirely legitimate to investigate these properties in full empirical detail. Sociologists, organizational theorists, and institutional researchers should be encouraged to investigate in detail the workings, arrangements, and causal properties of the regimes that they study. And this is precisely the kind of investigation that holds together researchers as diverse as Michael Mann, Kathleen Thelen, Charles Perrow, Howard Kimmeldorf, and Frank Dobbin. (Use the search box to find discussions of their work in earlier posts.)

What this implies is that sociologists can legitimately pursue meso- and macro-level inquiries into the nature of the social entities that most interest them. Organizational theory is an especially good example. We can approach the study of organizations from a number of points of view. But one perfectly legitimate approach is to attempt to discover some of the dynamic and causal properties of organizations with specified features. This takes the form of trying to discover what propensities a given organizational form has when embedded into a given institutional or social context. And this is a form of causal inquiry that is analogous to metallurgy or materials science: what are the properties of conductivity, thermal expansion, ductility, etc., of metals or ceramics of a given structural composition?

This means in turn that the ontology of individualism does not imply very much about methodology and research strategies. Ontology is not irrelevant to methodology; but it provides only weak constraints on the nature of the methodologies social scientists may choose in their pursuit of better understanding of the social world.

Can we say more about how ontological confidence about the nature of social entities is consistent with methodological pluralism? One part of the answer derives from the idea of the relative autonomy of various levels of the natural and social world. This is the argument that Jerry Fodor put forward with respect to the "special sciences" like psychology. Fodor argued persuasively that psychologists are entitled to investigate psychological properties without being obliged to reduce these properties to facts about the central nervous system. The rationality of science does not force us to be reductionist. Instead, it is legitimate to examine the properties of the system-level structures of a domain without attempting to say how these properties derive from more fundamental features of the stuff. And this has equally compelling implications for sociology as it does for other special sciences.

The upshot of this set of considerations is important for the conduct of social science. The ontological truism that social phenomena are constituted by individual-level activities does not imply that social science methodology must proceed along the lines of reductionism or aggregative explanation (vertical explanations, reproducing the struts of Coleman's boat). We can be individualist in ontology and macro-ist in our methodology.

The constraint of the ontological truism of microfoundationalism has really only two significant implications:

1. We need to be confident in general terms that there are microfoundations for a social property or power, even though we do not need to reproduce those micro foundations.
2. In special cases we may find that a reductionist or aggregativist strategy leads to a particularly straightforward explanation of a social-level fact (along the lines of Thomas Schelling's many examples).

But generally speaking, all of this suggests that we should be methodological pluralists in the social sciences -- make use of the research strategies that seem most promising for understanding a specific range of phenomena without a lot of concern for how the method aligns with our most refined ontological thinking.

Heterogeneity according to Cartwright

 

Nancy Cartwright is one of the best philosophers of science around, in many people's opinion. I find her work particularly interesting for the new ways she offers of thinking about old ideas like "laws of nature" and the ways things work in the natural world. Much of what she writes about the entities and processes of the natural world is equally perceptive when applied to the social world. Especially interesting is her 1999 book, The Dappled World: A Study of the Boundaries of Science.

In The Dappled World Cartwright focuses on an idea that I've highlighted many times here as well -- the idea of the fundamental heterogeneity of the world. Here are the opening words of the book:

This book supposes that, as appearances suggest, we live in a dappled world, a world rich in different things, with different natures, behaving in different ways. The laws that describe this world are a patchwork, not a pyramid. They do not take after the simple, elegant and abstract structure of a system of axioms and theorems. Rather they look like — and steadfastly stick to looking like — science as we know it: apportioned into disciplines, apparently arbitrarily grown up; governing different sets of properties at levels of abstraction; pockets of great precision; large parcels of qualitative maxims resisting precise formulation; erratic overlaps; here and there, once in a while, corners that line up, but mostly ragged edges; and always the cover of law just loosely attached to the jumbled world of material things. (1)

She is particularly interested in demolishing the quest for scientific unity — a single unifying theory that can be said to represent the whole of a field of natural or social phenomena. She firmly rejects the idealized notion that quantum mechanics deductively encompasses all areas of physics, or that rational choice theory encompasses all areas of the social sciences. Instead, she argues that the “patchwork” nature of the disciplines of the sciences — different definitions of domain, different ideas about methodology and proof — corresponds in a deep way to the patchwork nature of the world. So methodology and ontology are intermingled.

The problem is that our beliefs about the structure of the world go hand-in-hand with the methodologies we adopt to study it. The worry is not so much that we will adopt wrong images with which to represent the world, but rather that we will choose wrong tools with which to change it. (12)

One way that Cartwright chooses to explain her “dappled” notion of the world is to insist that all scientific laws require ceteris paribus conditions. So scientific laws — even supposedly fundamental laws of mechanics like F = ma — do not apply unconditionally; rather, they apply subject to specific statements of boundary conditions and isolation conditions. A scientific experiment is designed in such a way as to exclude the workings of extraneous forces or influences; but Cartwright observes that in the real world of experience, we almost never observe this kind of isolation. Instead, baseballs are conveyed through parabolic arcs by mass, momentum, air currents, humidity, and fluid frictions — leading to a resultant arc which is only approximately described by the mathematical formula of the hyperbola (25-27).

The idea that the laws of nature always bring with them a set of ceteris paribus conditions is one way of pointing to the heterogeneous nature of the world. But a different way of characterizing the overall behavior of the spherical solid baseball is to refer to its nature — the inherent properties of the thing that work to produce its causal powers. The fact that it is a material object gives it a disposition to move in accordance with the laws of inertia and gravitation. The fact that it has a leather skin gives it a disposition to interact with surrounding fluids in ways that create patterns of micro-turbulence. The fact that its center of gravity is not at the geometrical center of the sphere gives it a tendency to wobble in flight. Each of these properties of the thing give separable tendencies to motion when the object is disturbed (hit with a baseball bat).

If we use the language of a thing's “nature” then the laws of nature are doubly secondary: they are approximate; and they derive from something more fundamental, the ensemble of natures that inhere in the objects in question.

Here are the three core ideas that she puts forward (4):

1. The impressive empirical successes of our best physics theories may argue for the truth of these theories but not for their universality...
2. Laws' where they do apply, hold only ceteris paribus....
3. Our most wide-ranging scientific knowledge is not knowledge of laws but knowledge of the natures of things...

One consequence of Cartwright's views here, and her skepticism about the universality and generality of scientific laws, is a principled rejection of reductionism:

Not only do I want to challenge the possibility of downwards reduction but also the possibility of 'cross-wise reduction'. Do the laws of physics that are true of systems ... in the highly contrived environments of a laboratory or inside the housing of a modern technological device, do these laws carry across to systems, even systems of very much the same kind, in different and less regulated settings? (25)

And her answer to these questions is negative.

Cartwright's position has a lot in common with current work on causal powers, and this extends to her appeal to Aristotelian metaphysics as an alternative to Humean theories of regularities.

What kinds of facts (if any) determine the behaviour of a nomological machine? The Humean tradition, which finds nothing in nature except what regularly happens, insists that it must be further regularities. This chapter will continue the argument that laws in the sense of claims about what regularly happens are not our most basic kind of scientific knowledge. More basic is knowledge about capacities, in particular about what capacities are associated with what features. (77)

Where do laws of nature come from? ... It is capacities that are basic, and laws of nature obtain ... on account of the capacities; or more explicitly, on account of the repeated operation of a system of components with stable capacities in particularly fortunate circumstances. (49)

The idea of a nomological machine plays a central role in Cartwright's arguments; so what does this amount to? Cartwright is clear and explicit about this question:

What is a nomological machine? It is a fixed (enough) arrangement of components, or factors, with stable (enough) capacities that in the right sort of stable (enough) environment will, with repeated operation, give rise to the kind of regular behavior that we represent in our scientific laws. (50)

So a nomological machine is an important way of linking capacities and laws in Cartwright's account: it is a bundled set of special circumstances that give rise to the sorts of strong regularities that Humeans are looking for. But Cartwright's key point is that these circumstances are very special indeed: controlled laboratory setups and isolated technical devices are the examples she offers. This gives substance to the three core ideas articulated above: crucially, the construct illustrates the lack of universality and generality for scientific laws that she thinks is ineliminable in the study of nature (and society).

Cartwright develops these ideas largely in the context of the physical sciences. But she has been an important contributor to the philosophy of economics and the social sciences as well. And her skepticism about governing laws is even more compelling in the latter realms. As I tried to articulate the point in “On the Scope and Limits of Generalizations in the Social Sciences" (1993; link), we should think of regularities in the social world as phenomenal rather than governing. The social regularities we observe are the consequence of the workings of social mechanisms, and we should not imagine that there is an underlying set of governing laws that "generate" the social world.

Domain of the social sciences

 

Is the domain of "all social phenomena" a valid subject for scientific study? Is there a place for a purely general sociology, designed to be a theory of the social everything? Sociologists from Comte to Parsons have sometimes put forward this idea, and James Coleman pursued something like this in Foundations of Social Theory. But upon reflection, this seems like the wrong way of thinking about the social world.

Instead, the social world consists of a hodge-podge of actions, rules, organizations, motives, and the like, at a wide range of scales (link, link). A key task for social scientists is to segment social phenomena into related groups of actions or entities, with a scientific goal of making sense of how these various kinds of stuff work. So social scientists should permit themselves to be eclectic and specialized, identifying sub-domains of interest and uncovering the mechanisms and processes that are at work in this area of social life.

These considerations make it understandable that social research focuses on specific groups of social phenomena like these -- contention, organizations, racial discrimination, norm systems, market behavior, voting behavior, families, delinquency, .... These are all selected groups of social action and structures, similar enough to admit of a condensed description of what unifies them and plausibly explained by a similar set of causal mechanisms and processes. This provides a logic to the separation of the discipline of sociology into a large number of sub-disciplines; as of last count the American Sociological Association encompassed 52 sections, each organized around a set of research topics and methods (link).

Consider a possible analogy. Suppose we have just arrived on planet Earth and have noticed that we are surrounded by noises, and we want to understand this blooming, buzzing confusion. More exactly, we "hear" a wide range of phenomena with qualitative properties through our auditory sensory systems. And suppose we wanted to formulate a science of sound. How would we proceed?

We wouldn't begin, most likely, by collecting and cataloging the sounds that we perceive -- birds tweeting, jets roaring, children singing, elephants rumbling, ... No, we would begin by trying to determine what "sound" is (what the physical phenomenon is that underlies the phenomenology of sound through our hearing system). We will answer that question fairly quickly -- "sound is the result of vibrations in a medium in a certain range of frequencies, conveyed through a medium that extends from the vibrating object to the sensory detectors in our inner ears." And then the vast majority of sounds will be disregarded as scientifically uninteresting. The essentials have been identified: a source of vibration and a medium of transmission. More interesting will be the anomalies -- harmonics, differential speeds of propagation, echoes, Doppler effect, ... And we will be interested in the non-obvious mechanisms of sound production and transmission.

I'm not really interested in sounds, but rather in social phenomena. But there is a possible analogy here. The social world that we observe presents a bewildering variety of social phenomena. Where should we start in formulating a science of society? Perhaps the clue from acoustics and sound is this: we can ignore much of the phenomena, identify the surprising bits, and look for the mechanisms that underlie this surprising outcome or that. It is the fact of patterns and recurring surprises that will be of primary scientific interest.

There is a unifying feature of all sound phenomena — vibrations in a medium. And likewise, there is a unifying feature of all social phenomena — real human beings interacting with each other on the basis of their own mental maps of the world around them and conceptions of where they are trying to go, subject to constraints created by the natural environment and the behaviors and practices of individuals around them. But the real substance of research in both fields takes place at a more refined level, in which researchers seek to identify mechanisms and explanations for apparently anomalous outcomes.

What this thought experiment suggests is that we should not think of the subject matter of social science as the domain of all social action and social phenomena. Rather, much of what we observe in social life can be put in the category of noise, best filtered out as we focus our attention on surprising outcomes and mechanisms that permit of substantial illumination and explanation. The real subject matter is various bundles of related phenomena where we have succeeded in finding some important structural similarities and some relevantly similar causal mechanisms.

And we shouldn’t hold out the chimera of a unified social theory that explains all social phenomena — whether rational choice theory, world systems theory, or psychoanalysis.

*              *              *

This is the conclusion that I am inclined to support. But there is a different way of taking this analogy which comes back to giving greater support to James Coleman's aspirations in Foundations of Social Theory. If it is agreed that there is a unifying feature underlying all social behavior --

real human beings interacting with each other on the basis of their own mental maps of the world around them and conceptions of where they are trying to go, subject to constraints created by the natural environment and the behaviors and practices of individuals around them

-- then we might argue after all that "general sociology" is possible after all. It would consist of (a) discovery of the premises that govern the actors, (b) exploration of the most important ways in which actors interact, and (c) exploration of some of the specific boundary conditions within which (a) and (b) play out in the actual social world. Much of the variation represented in the list of the sections of the ASA above takes the form of enumeration of special cases in category (c). But the general science of sociology is contained in (a) and (b).

This gloss on the story also conforms to some extent to the science of acoustics: a common set of principles defining the physics and mathematics of the production and propagation of vibration through a medium, and a set of special cases where these principles produce odd results.

*           *            *

These contradictory conclusions point to a central tension within sociological theory between greater generalization and greater attention to context and variation. (This tension is highlighted in the recent post on Peggy Somers' rebuttal to Kiser and Hechter; link.) But I'm forced to acknowledge that this is also a tension in my philosophy of social science as well. The question of the availability of general theories in sociology relates to my own advocacy for the idea of methodological localism -- the idea that all social phenomena derive from the actions and thoughts of locally situated and locally constructed individual actors in proximate relations to other actors. "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). But this formulation seems to leave it open that we might aspire to having general theories of the actor that permit us to explain social outcomes in terms of the features of action that are identified. And that seems to be the program that Coleman is exploring in Foundations.

Are there meso-level social mechanisms?

It is fairly well accepted that there are social mechanisms underlying various patterns of the social world — free-rider problems, communications networks, etc. But the examples that come readily to mind are generally specified at the level of individuals. The new institutionalists, for example, describe numerous social mechanisms that explain social outcomes; but these mechanisms typically have to do with the actions that purposive individuals take within a given set of rules and incentives.

The question here is whether we can also make sense of the notion of a mechanism that takes place at the social level. Are there meso-level social mechanisms? (As always, it is acknowledged that social stuff depends on the actions of the actors.)

This question is analogous to two other similar issues in other special sciences:

• Are there information-system level causal mechanisms in human cognition?
• Are there cellular-level causal mechanisms in biological systems?

Or, to the contrary, are all mechanisms in sociology, cognition science, and biology properly understood to be carried out at the level of individuals, neurons, and biochemistry?

Here is my version of a definition of a causal mechanism (link):

A causal mechanism is (i) a particular configuration of conditions and processes that (ii) always or normally leads from one set of conditions C to an outcome O (iii) through the properties and powers of the events and entities in the domain of concern. 

And here is the definition offered by Doug McAdam, Sidney Tarrow, and Chuck Tilly in Dynamics of Contention:

Mechanisms are a delimited class of events that alter relations among specified sets of elements in identical or closely similar ways over a variety of situations. (kl 354)

We should begin by asking what it is that we are looking for. What would a meso-level mechanism look like?

Here is a start: it would be a linkage between two conditions or entities, each of which is itself a meso-level structure or entity. So a meso-level causal mechanism is one in which both C and O are meso-level entities or conditions and where C leads to O "always or normally".

Earlier I argued that meso-level entities possess causal powers: regular dispositions to produce specified effects, grounded in the substrate of social activity (link). If some of those effects O_i are themselves meso-level outcomes or structures, then our question here is answered. Any pair {C,O_i} is itself a meso-level causal mechanism. If, on the other hand, the causal powers of meso-level entities are restricted to changes in the behavior of individuals, then meso-level mechanisms do not exist.

McAdam, Tarrow, and Tilly address a very similar question in Dynamics of Contention, and they argue for what they call "relational mechanisms":

Relational mechanisms alter connections among people, groups, and interpersonal networks. Brokerage, a mechanism that recurs throughout Parts II and III of the book, we define as the linking of two or more previously unconnected social sites by a unit that mediates their relations with one another and/or with yet other sites. Most analysts see brokerage as a mechanism relating groups and individuals to one another in stable sites, but it can also become a relational mechanism for mobilization during periods of contentious politics, as new groups are thrown together by increased interaction and uncertainty, thus discovering their common interests. (kl 376)

Having formulated the question in these terms, it seems that we can provide a credible affirmative answer: it is possible to identify a raft of social explanations in sociology that represent causal assertions of social mechanisms linking one meso-level condition to another. Here are a few examples:

• Al Young: decreasing social isolation causes rising inter-group hostility (link)
• Michael Mann: the presence of paramilitary organizations makes fascist mobilization more likely (link)
• Robert Sampson: features of neighborhoods influence crime rates (link)
• Chuck Tilly: the availability of trust networks makes political mobilization more likely (link)
• Robert Brenner: the divided sovereignty system of French feudalism impeded agricultural modernization (link)
• Charles Perrow: legislative control of regulatory agencies causes poor enforcement performance (link)

We might also consider the possibility of compound meso-level mechanisms, in which M₁ produces M₂ which in turn produces M₃. Does the sequence also qualify as a mechanism? That depends on the strength of the relationships that exist at each link; if the conditional probabilities of the links fall low enough, then the compound probability of the chain is no longer sufficient to satisfy condition (ii) above ("initial condition normally leads to the outcome").

Essentially this question comes down to the tightness of the linkages that exist among the sub-components of social systems. If there are sub-components within bureaucracies that maintain their properties and are tightly linked to specified outcomes, then these can play a role within meso-level causal mechanism narratives. If, on the other hand, the effects of a given subcomponent of a social system vary widely over time and space, then that type of component does not play a useful role in a causal mechanisms analysis. So the question of how extensive meso-level causal mechanisms are is itself an empirical one; it depends on the specific features of the social world.

So it seems as though we can offer two related conclusions about the causal reality of meso-level entities: meso-level structures possess causal powers, and there are causal mechanisms that invoke meso-level entities as both input and output.