Hempel after 70 years

Carl Hempel published his sole contribution to the philosophy of history in 1942, almost exactly 70 years ago. The article is "The Function of General Laws in History" (link), and it set the stage for several fruitless decades of debate within analytic philosophy about the nature of historical explanation. Hempel argued that all scientific explanation has the same logical structure: a deductive (or probabilistic) derivation of the explanandum from one or more general laws and one or more statements of fact. Explanation, in Hempel's view, simply is "derivation of the explanandum from general laws." Here is the opening paragraph of the essay.

It is a rather widely held opinion that history, in contra-distinction to the so-called physical sciences, is concerned with the description of particular events of the past rather than with the search for general laws which might govern those events. As a characterization of the type of problem in which some historians are mainly interested, this view probably can not be denied; as a statement of the theoretical function of general laws in scientific historical research, it is certainly unacceptable. The following considerations are an attempt to substantiate this point by showing in some detail that general laws have quite analogous functions in history and in the natural sciences, that they form an indispensable instrument of historical research, and that they even constitute the common basis of various procedures which are often considered as characteristic of the social in contradistinction to the natural sciences. (35)

And here is the logical structure of such a "covering law" explanation, according to Hempel:

(1) a set of statements asserting the occurrence of certain events C1, . . . C, at certain times and places,
(2) a set of universal hypotheses, such that
          (a) the statements of both groups are reasonably well confirmed by empirical evidence,
          (b) from the two groups of statements the sentence asserting the occurrence of event E can be logically deduced. (36)

He is emphatic, moreover, in insisting that valid explanations in history must have this form:

We have tried to show that in history no less than in any other branch of empirical inquiry, scientific explanation can be achieved only by means of suitable general hypotheses, or by theories, which are bodies of systematically related hypotheses. (44)

Hempel concedes the point that few existing historical explanations actually look like this, with explicit law statements embedded in a deductive argument; but he argues that this shows only that existing explanations are elliptical, incomplete, or invalid. And often, he finds, what is offered as a historical explanation is in fact no more than an "explanation sketch" (42), with placeholders for the general laws.

What kinds of general laws does Hempel think that historians have in the back of their minds when they offer elliptical explanations? He refers to regularities of individual or social psychology (40), regularities of collective behavior ("groups migrate to regions which offer better living conditions"), or at the macro level, regularities linking growing discontent to the outbreak of revolution (41). Further:

Many of the universal hypotheses underlying historical explanation, for instance, would commonly be classified as psychological, economical, sociological, and partly perhaps as historical laws; in addition, historical research has frequently to resort to general laws established in physics, chemistry, and biology. (47)

This set of assumptions leads to big trouble for historical explanation if we accept Hempel's account, however, because it is hard to think of a real historical research question where there might be a set of social or individual regularities sufficient to deductively entail the outcome. Bluntly, the social and behavioral sciences have never produced theories of individual or collective behavior that issue in statements of general laws that could be the foundation for a covering law explanation. And given that social phenomena are formed by actors with a range of features of agency and decision-making, we have very good reason to think that this lack of regularities is inherent in the social world. The social world is simply not governed by a set of social or individual laws. Let's look at that point at several levels.

Individuals. The social sciences provide a good basis for advancing theories of agency, which in turn support certain generalizations about action. For example: People act out of self interest. People act morally. People pay attention to the example of others. People care about their families and friends. People follow charismatic leaders. People follow the precepts of their religious beliefs. People are emotional and short-sighted. People make decisions based on specific heuristics and rules-of-thumb. Each of these statements takes the form of a generalization. And each is true -- of some delimited groups of agents some of the time. But there is no generalization about agency that is true of all agents all the time. Rational choice theory attempts to provide a single theory of agency and decision making that replaces all of these variant grounds of action. But rational choice theory has proven notoriously unsuccessful as a foundation for explanation of a large and complex event -- war, revolution, economic crisis.

Groups. Here too we can identify some partial regularities: Groups tend to coalesce in action when they have prominent shared characteristics.  Groups are more prone to panic than individuals. Groups tend to fail to accomplish collective purposes. Groups are hyper-sensitive to racial and ethnic markers.  And so forth. It is evident that these are partial, tendential, exception-laden, and inexact; not at all like the generalizations that characterize metals, liquids, or proteins.

Organizations and institutions. What about mid-level social arrangements like labor unions, congregations, and terrorist cells? It's not that there aren't any generalizations to be had concerning items at this level; it is that there are too many, and they are highly contingent, conditioned, and contradictory. Certain types of organization are more prone to accidents than others.  This is true; but we have more confidence in our analysis of the most important features of the high-safety organization than we have in the corresponding generalization.  So there isn't a stockpile of laws that might be produced to apply to a social situation and then turn the crank and derive the deductive consequences.

Finally, what about large-scale events and structures -- wars, revolutions, civil conflict? Here too there are some generalizations that social scientists have asserted. For example: Democracies don't go to war with each other. War is made more likely when two powers have conflicts of interest over important resources. Wars create propaganda.  Revolutions don't happen when the general population is satisfied. But generalizations about these sorts of social entities too are bounded and unreliable. They are conditional, we recognize immediately that they have exceptions, and they don't permit prediction.

So the strong, governing generalizations that would be needed for a covering law explanation do not exist. As I argued a number of years ago, social regularities are phenomenal, not governing (link); they reflect characteristics of the actors rather than governing the behavior of the ensembles.  Does this mean that historical explanation is impossible?  No.  But we need to turn our attention from regularities to causal mechanisms and powers in order to see what a good historical explanation looks like.  A good historical explanation identifies a number of independent mechanisms and processes that are at work in a particular circumstance, and then demonstrates how these mechanisms, and the actions of the actors involved, lead to the outcome.

Doug McAdam, Sidney Tarrow, and Chuck Tilly advanced a boldly different approach to analyzing and explaining complex historical phenomena, with special application to social contention.  They rejected the idea that there might be "laws" of revolution, civil unrest, or ethnic cleansing. They argued instead that there are a number of recurring "social mechanisms" of contention that can be identified in many instances of contention, and whose influences can be traced out to result in the observed outcomes.  Here is how McAdam, Tarrow and Tilly proceed in Dynamics of Contention.

We begin with a question: What led normally accepting accepting African-Americans both in Montgomery and throughout the South to risk their livelihoods and their lives in support of civil rights? Recall from Chapter I that in the "classical social movement agenda" the following factors come into play: 

• Social change processes initiate a process of change and trigger changes in the political, cultural, and economic environments. 
• Political opportunities and constraints confront a given challenger. Though challengers habitually face resource deficits and are excluded from routine decision making, the political environment at any time is not immutable; the political opportunities for a challenger to engage in successful collective action vary over time. These variations shape the ebb and flow of a movement's activity. 
• Forms of organization (informal as well as formal) offer insurgents sites for initial mobilization at the time opportunities present themselves and condition their capacity to exploit their new resources. Despite some evidence to the contrary (Piven and Cloward 1977), a large body of evidence finds organizational strength correlated with challengers' ability to gain access and win concessions (Gamson 1990). 
• Framing, a collective process of interpretation, attribution, and social construction, mediates between opportunity and action. At a minimum, people must both feel aggrieved at some aspect of their lives and optimistic that acting collectively can redress the problem (Snow, et al. 1986; Snow and Benford 1988). Movements frame specific grievances within general collective action frames which dignify claims, connect them to others, and help to produce a collective identity among claimants. 
• Repertoires of contention offer the means by which people engage in contentious collective action. These forms are not neutral, continuous, or universally accessible; they constitute a resource that actors can use on behalf of their claims (Traugott, et al. 1995). The use of transgressive forms offers the advantages of surprise, uncertainty, and novelty, but contained forms of contention have the advantage of being accepted, familiar, and relatively easy to employ by claimants without special resources or willingness to incur costs and take great risks.

That classical agenda made three enduring contributions to the study of social movements. First, it made strong claims regarding the close connection between routine and contentious politics, helping to reframe the study of social movements as the proper province of both sociology and political science. Second, calling attention to the role of "mobilizing structures," it represented a powerful challenge to the stress on social disorganization and breakdown in the older collective behavior paradigm. Third, it produced a credible picture of mobilization into social movements that was supported by a good deal of empirical evidence correlating the factors outlined above with increases in mobilization.

There are low-level generalizations offered throughout this series of statements. But all those generalizations are soft and exception-laden.  What MTT are interested in doing when they attempt to explain what they call "episodes of contention" is rather to identify the occurrence and interaction of a number of common mechanisms of contention.  And in fact, they explicitly repudiate the covering law model:

Our emphasis on recurring mechanisms and processes does not mean that we intend to pour all forms of contention into the same great mold, subjecting them to universal laws of contention and flattening them into a single two-dimensional caricature. On the contrary, we examine partial parallels in order to find widely operating explanatory mechanisms that combine differently and therefore produce different outcomes in one setting or another. To discover that third parties influence both strikes and ethnic mobilization by no means amounts to showing that the origins, trajectories, and outcomes of strikes and ethnic mobilization are the same, any more than identifying similarities in memory processes of mice and men proves mice and men to be identical in all regards. To discover mechanisms of competition and radicalization in both the French Revolution and in the South African freedom movement is not to say that the Jacobins and the African National Congress are the same. We pursue partial parallels in search of mechanisms that drive contention in different directions. Only then, and in Part III, do we examine how mechanisms combine in robust political processes.

Seventy years after Hempel's classic article, the covering law theory is now generally regarded as a fundamentally wrong-headed way of thinking about historical (and social) explanation.  Logical positivism is not a convenient lens through which to examine the social and historical sciences.  There is too much contingency in the social world. Rather than being the result of law-governed processes, social outcomes proceed from the contingent and historically variable features of the actors who make them.  So the attention of many people interested in specifying the nature of historical and social explanation has focused on social mechanisms constituted and driven by common features of agency.

(Renate Mayntz's discussion of causal mechanisms represents one of the best current treatments of the subject; link.)

Ordinary and theoretical knowledge of capitalism

John Levi Martin argues in The Explanation of Social Action, among other things, that we need to understand the social world through the ways it is experienced by participants. "Sociology and its near kin have adopted an understanding of theoretical explanation that privileges 'third-person' explanations and, in particular, have decided that the best explanation is a 'causal' third-person explanation, in which we attribute causal power to something other than flesh-and-blood individuals" (kl 75). He thus criticizes sociological theorizing because it is third-person and aims to explain social arrangements in terms foreign to the participants.

But this is really what the act of "theorizing" always involves, and why it is important. The social world always exceeds the vision of the participants, and though Levi Martin cringes at the thought, there are in fact distant, unseen structures and systems that constrain local experience. The role of theory -- one role, anyway -- is to discover in thought what some of those systemic processes and forces are. "Capitalism," "trading system," "sugar-cotton-slave nexus," "finance capital," and "bourgeois ideology" are all theoretical formulations designed to connect the dots -- to draw attention to the systems within which everyday experience takes place. And those systems exist and have consequences for individuals at all levels of agency -- beliefs, assumptions, purposes, incentives, and constraints.

It is of course true that social entities at every level require microfoundations. So it isn't quite right to say that social entities convey effects through something other than flesh-and-blood individuals. But this does not mean that they do not convey effects onto individuals and local arrangements that are beyond the ken of the local actors.

Take the complex of ideas associated with Marx's conception of materialism as an example, and put yourself in a particular historical setting--say British factory expansion in the 1830s and 1840s. Participants at every location had perceptions and ways of talking about their experiences. The recently "freed" factory worker in Manchester had his perspective; the dockworker in London had his; the "putting-out" spinner had hers; the Caribbean slave had his and hers; and likewise the baker, the tailor, and the candlestick maker. For that matter, Marx, Engels, and Carlyle were participants too, and they made their own efforts to conceptualize and explain their experience. They wanted to say what was going on.

But here is the crucial point; none of them really got it. They got parts of the story -- the harsh conditions in the factory, the swirl of new finance activity, the overseers' whip, the living conditions in slums in Birmingham, Manchester, and London, the stench of the River Irk, and much else. But none was in a position to perceive the relationships among these social locations.

These are all fragments of the picture, and as Marx insisted in Capital when he discussed commodity fetishism -- some of these perspectives conceal rather than expose the system of social relations that was emerging. It took something else in order to cognize "emerging capitalist urban industrial society". Carlyle did his part (he coined the phrase, the "cash nexus"); so did Engels and Marx; and so have Gramsci and Wallerstein. Theorizing was necessary in order to transform the partial and sometimes mystifying bits of ordinary experience into a more revealing system-level understanding. The worker perceives the temporal coercion of the factory; but he and she do not perceive the larger social structures that explained that system of organization.

Is the participant-level even the right perspective from which to try to identify an explanation? I don't think so. Were conditions in this factory harsh because this owner was hostile or cruel towards these particular workers? No, rather because the competitive environment of profitability and accumulation created an inexorable race to the bottom. So we can't explain this factory's working conditions by referring to specific features of this factory and its owner. This logic is spelled out very clearly in Capital, and it is a system-level characteristic.

Here is what Levi Martin has to say about this line of argument, early in ESA. He paraphrases the argument in these words:

Actors may see the little picture -- particularities that while undeniable are still ignorable -- but they do not produce the sweeping abstractions that have important implications across many domains of social life. It is these general abstracts that, when linked in some system, deserve the credit of behing "theory, and the more surprising the implications -- the less they agree with the particular, everyday knowledge of actors -- the more brilliant the theory is if confirmed. (kl 104).

It is plain that L-M does not accept this move from the particular local knowledges to a more abstract "theory" that connects the dots. He favors instead a mode of theorizing that derives from phenomenology:

Phenomenology in this sense is the study of how every-day people orient themselves to the world and how they determine what needs to be done. (kl 152)

But it is likely that no one within the emerging factory system in Manchester or Birmingham would have experienced the system-level factors that shaped the emergence of that system. The self-conception of the capitalist factory owner is "modernizer," "bringer of better life prospects to immigrant Irish peasants," or "contributor to a new Britain" -- not "cog in a system of profit-maximizing competition where to lose one's footing in pushing costs down is to drown."

So how do distant, impersonal social forces impinge on local experience? This is the nexus that draws the greatest skepticism from Levi Martin. But it isn't particularly difficult to answer. Take the rapid development of tenements and slums that Engels describes in The Condition of the Working Class in England. The expansion of trade, rapidly rising demand for finished goods, and the workings of financial markets are the distal causes that shaped the choices of capitalists, city fathers, and legislators, and these choices compounded to the misery described by Engels. This is the value of Immanuel Wallerstein's work; he helps demonstrate these distal relations and systemic interrelationships (The Modern World-System I: Capitalist Agriculture and the Origins of the European World-Economy in the Sixteenth Century, With a New Prologue).  And I don't think that Wallerstein's work is at all incompatible with an actor-centered, microfoundational view of social causation.

Response to Little by John Levi Martin

[John Levi Martin accepted my invitation to write a response to my discussion of his Explanation of Social Action (link).  John is professor of sociology at the University of Chicago and author of Social Structures in addition to ESA.  Thanks, John!]

Response to Little
by John Levi Martin

The Explanation of Social Action (henceforward, ESA) is a book about the explanation of social action. It argues that there are fundamental instabilities in what seems to be the dominant approach to such explanation in the social sciences, which it terms explanation via third person causality (TPC). TPC is when we attempt to explain the action of persons (say, they vote for a Republican) using entities that are not themselves persons, and attribute causal power to such entities (say, income and authoritarianism cause Republican voting). Examinations of TPC are wrecked if the recipients of the causal force willfully “select” themselves to be exposed to causes. ESA is not the first book to point to the instabilities that result, but previous arguments do not seem to have affected the progression of the social sciences, which operate on the Warner Brothers’ principle that even if you have run off a cliff and there is nothing under your feet, you will not actually fall so long as you do not look down.

As said above, ESA is a book about the explanation of social action—it does not claim to cover everything that social scientists find interesting and important. However, one of the problems with the contemporary approach to the social sciences is that cases of social action are disguised in ways that lead to confusion. Thus Little writes that ESA’s scope fails to include “‘Why?’ questions [that] involve understanding the workings of institutions and structures.” Such questions—e.g., “why did the decision-making process surrounding the launch of Space Shuttle Challenger go so disastrously wrong?”—Little says, “admit of causal explanations. And they are not inherently equivalent to explanations of nested sets of social actions.”

Were this the case, the arguments of ESA would indeed be less damaging. But it is not at all obvious that such “workings of institutions and structures” are not “equivalent to…sets of social actions.” While “workings of institutions and structures” is a fine figure of speech for approximate purposes, speaking more exactly, institutions do not work, or cause, or act, or think. Institutions are nothing other than sets of actions—“patterns of repeated conduct.” When we ignore this, we produce unstable explanations.

Indeed, Little’s example is enlightening. Consider Vaughan’s justly famous The Challenger Launch Decision: Risky Technology, Culture, and Deviance at NASA. This is a wonderful piece of research. But when Vaughan boils things down to a (general) sociological conclusion, it seems of the form “institutional culture caused this decision to be of this sort.” As I am sure a number of people have pointed out, as institutional culture is itself nothing other than the pattern of social action that takes place in the institutional setting, this is to take the pattern of action, pull out one part, put it by itself, draw a line from the rest of the pattern to this one part, and write “causes” on the line. This is a very confusing way of proceeding and formally like the case (treated in ESA) of explaining someone’s favoring of an authoritarian policy by saying that it was “caused” by his authoritarianism. It is taking a tautology and adding a mystical confusion in the form of “causality.” Vaughan’s arguments in detail are important, but we would do better to return to Peirce, James and Dewey and to examine the formation of habits than to posit some new realm of “institutions and structures” with their own causality.

The problems with our desperate belief in causation even where it adds nothing but confusion is best seen in the line of work emphasized by Little on causal “mechanisms.” I did not devote any of ESA to a critique of these ideas in part because I believed that my general points were best made without “going negative,” because I believed that Tilly’s approach to explanation was an improvement over most others, and because of my great admiration for and gratitude to Charles Tilly. This opened space for confusion.

Tilly identifies recurring patterns of social action and calls these “mechanisms” because they can be envisaged as discrete parts of a clockwork that, assembled in a certain way, will produce a certain result. In itself, this is a laudable endeavor; the word “mechanism” to describe the pattern nicely highlights the modular nature of these explanatory nuggets, at the cost of some misleading imagery. But to call these accounts “causal” and to argue that this demonstrates the stability of TPC seems very puzzling. For the mechanisms themselves are nothing other than patterns of action. They do not explain the action, they are it.

For example, Tilly lists “coalition formation between segments of ruling classes and constituted political actors that are currently excluded from power” (henceforward, CFBSORCACPACEFP) as a “mechanism” tending to “cause” democratization. Speaking loosely, this is all well and good, but it cannot be seen as a successful form of TPC. For this requires us to imagine some form of CFBSORCACPACEFP that is forced upon persons as opposed to arising from their own actions (a relation between CFBSORCACPACEFP and democracy interpreted in motivational terms would not support the doctrine of the existence of TPC). Certain cases are more like this extreme scenario and others less like, but no case can perfectly satisfy this vision, because it requires action without action. The more seriously we take the causal language, the sillier or crazier our thoughts become.

In sum, our “run fast and don’t look down” strategy has led us to take outcomes (what happens) and reify them into causes (these are “constraints” and “structures”), and to take patterns of actions and claim that they are not patterns of action at all, but something else that in fact causes these actions. We are akin to meteorologists unwilling to abandon the idea that there really are Winds (e.g., the Zephyr) with their own causal properties, and who abuse any colleagues so simplistic as to insist that to make any scientific progress, they will need to produce accurate models for compressible gasses and then scale up. ESA is about how we might start.

Levi Martin on explanation

John Levi Martin's The Explanation of Social Action is a severe critique of the role of "theory" in the social sciences. He thinks our uses of this construct follow from a bad conception of social explanation: we explain something by showing how it relates (often through law-like processes) to something radically different from the thing to be explained. But Levi Martin adopts one strand of Weber's conception of sociology -- "the science of meaningful social action" (kl 92) -- and advocates a fundamentally different conception of sociological thinking. Let us explain why social things happen in terms of the ways that ordinary people understand their actions and meanings. Levi thinks the usual approach is Cartesian, in that it presupposes a radical separation between the individual who acts and the considerations that explain his/her action.

Sociology and its near kin have adopted an understanding of theoretical explanation that privileges "third-person" explanations and, in particular, have decided that the best explanation is a "causal" third-person explanation, in which we attribute causal power to something other than flesh-and-blood individuals. (kl 75)

His own approach is anti-cartesian -- explanans and explanandum are on the same level.

The main argument of this book may be succinctly put as follows: the social sciences (in part, but in large part) explain what people do, and they explain what it means to carry out such an explanation. (kl 14)

Rather than drawing on examples from the law-based natural sciences, he prefers to understand actors in their own terms, and he offers the example of three antecedent theories:

But there are alternatives. I trace three, all of which dissented from the Cartesian dualism underlying the Durkheimian approach. These are the Russian activity school (with Vygotsky the prime example), the German Gestalt school (with Kohler the prime example), and the American pragmatist school (with Dewey the prime example). All point to a serious social science that attempts to understand why people do what they do, a science that while rigorous and selective (as opposed to needing to "examine everything") is not analytic in the technical sense of decomposing unit acts into potentially independent (if empirically interrelated) components. (kl 147)

I like Levi Martin's work quite a bit, and wrote earlier on his approach to social structures in his Social Structures (2009). But here I do not finding his reasoning as persuasive.

First, his account leaves out a vast proportion of what many social scientists are interested in explaining -- why did fascism prevail in Germany and Italy, why were East Coast dock worker unions corrupt while West Coast dock workers were political, why do young democracies fall prey to far-right nationalist movements, why did the decision-making process surrounding the launch of Space Shuttle Challenger go so disastrously wrong? These Why questions involve understanding the workings of institutions and structures, and they admit of causal explanations. And they are not inherently equivalent to explanations of nested sets of social actions.

Second, L-M's polemic against current ideas of social explanation assumes there are only two choices in play: correlational studies of associated variables and actor-level explanations of why people behave as they do. But this is incorrect. The new institutionalism in sociology, for example, explains outcomes as the result of a socially embedded system of rules that produce a characteristic set of actions on the part of participants. Institutional differences across settings lead to significantly different outcomes. And the causal-mechanisms approach to explanation (Tilly) identifies meso-level social mechanisms that can be seen to aggregate into identifiable social processes. L-M's polemic against "causalism" is, in my perception, directed against an untenable regularity-based theory of causation; but the causal-mechanism approach provides a far more defensible theory of social causation and explanation.

Third, his current account is mono-thematic: the only thing that counts is what is in the head of the participant. But this seems wrong in two ways: first, we are often interested in social facts that are not social actions in Weber's sense. And second, sometimes factors that the individuals themselves have not conceptualized are critical to understanding what is going on.

I also find that Levi Martin gives the causal mechanisms approach a wholly unfair dismissal. The CM approach is actually an alternative way of disaggregating social explanations and de-dramatizing the quest for unifying theories of the social world. The CM approach brings forward a heterogeneous view of the workings of a social world that is itself heterogeneous and multi-factoral. It is a mid-level theory of explanation, not a generalization-worshipping theory of explanation. So I believe that much of what Levi says in favor of his own approach can be said with equal force about the CM theory.

Moreover, CM theory too is an actor-centered approach to social explanation. The mechanisms to which sociologists in this tradition appeal work through the choices and actions of individuals. But CM also recognizes that there are relatively stable structures and relations that influence individual action and that have consequences for yet other meso-level factors. The CM approach asks a great fundamental question: through what processes and mechanisms did the social phenomenon in question take place? And crucially, there is no reason to expect the participants to conceptualize or understand these mechanisms and institutions. So there is a proper place for the hypotheses and constructs of the observer and theoretician after all.

One way to put these criticisms is to suggest that the book is mis-titled. The title offers a comprehensive theory of social explanation, but it doesn't in fact succeed in providing any such thing. And it gives the impression that there is only one legitimate mode of social explanation -- something that most sociologists would reject for good reasons.

In fact, the book is not so much a theory of explanation as it is a theory of the actor: what she knows, what she wants, how she chooses, and how she acts. It is a theory that draws upon American pragmatism and phenomenology. And the implication for "explanation" is a very simple lemma: "Explanations of social actions need to be couched in terms of the real experiences and cognitive-practical setup of the actors." Here is the title I would have preferred: "Towards a More Adequate Theory of the Human Actor".

Here, then, is the heart of my assessment of The Explanation of Social Action: L-M reduces the many explanatory tasks of the social sciences to just one -- the explanation of meaningful social actions by individuals. There is more to sociology than that, and identifying causal structures and mechanisms is a legitimate sociological task that has no place in L-M's conceptual space here. But as a contribution to the topic to which it is really directed -- the attempt to formulate a more adequate theory of the actor -- I believe it is a major contribution.

Neighborhood effects as meso-causes

A very interesting and current sociological study of "meso"-social causation can be found in the literature on neighborhood effects over the past 15 years or so. Robert Sampson and various colleagues have offered striking new analyses and arguments that establish the importance of geo-social neighborhoods on the occurrence of a variety of important social behaviors.  And their thinking represents a concrete, empirically rigorous and theoretically well developed effort to probe the effects and mechanisms that link neighborhood to resident.

Sampson, Morenoff and Gannon-Rowley provide a review of this literature in "Assessing 'Neighborhood Effects': Social Processes and New Directions in Research" (link). Sampson's contribution to the Demeulenaere volume, Analytical Sociology and Social Mechanisms, makes explicit the connection of this line of argument to issues about causation and methodological individualism that have been important to the analytical sociology movement.

Here is the preliminary definition of "neighborhood" upon which Sampson et al depend:

Robert Park and Ernest Burgess laid the foundation for urban sociology by defining local communities as “natural areas” that developed as a result of competition between businesses for land use and between population groups for affordable housing. A neighborhood, according to this view, is a subsection of a larger community—a collection of both people and institutions occupying a spatially defined area influenced by ecological, cultural, and sometimes political forces (Park 1916, pp. 147–154). Suttles (1972) later refined this view by recognizing that local communities do not form their identities only as the result of free-market competition. Instead, some communities have their identity and boundaries imposed on them by outsiders. Suttles also argued that the local community is best thought of not as a single entity, but rather as a hierarchy of progressively more inclusive residential groupings. In this sense, we can think of neighborhoods as ecological units nested within successively larger communities. ("Assessing," 445)

What Sampson and his co-authors want to discover is how sociologists have begun to identify and measure features of "neighborhoods" that are not simply aggregate features of individual behaviors, and how they have attempted to identify causal relations between these meso-level neighborhood characteristics and individual-level behaviors and outcomes.  They are particularly interested in health outcomes and other forms of disadvantage for children and adolescents, or what they term "problem-related or health-compromisingbehaviors among children and adolescents" (448): "infant mortality, low birthweight, teenage childbearing, dropping out of high school, child maltreatment, and adolescent delinquency" (446).

A key fact about neighborhoods and larger communities in the United States is the salience of race and poverty in residential patterns; neighborhoods are usually characterized by a concentration of racial groups and income groups.  And high-poverty, high-racial-minority neighborhoods are frequently characterized by high-negative-health outcomes.  But this is a mere correlation; what are the causal linkages between a neighborhood's characteristics and the health and behavioral outcomes of its residents?  In other words, they want to know something about the mechanisms through which these meso-level properties influence the individual resident:

During the 1990s, a number of scholars moved beyond the traditional fixation on concentrated poverty and began to explicitly theorize and directly measure how neighborhood social processes bear on the well-being of children and adolescents. Unlike the more static features of sociodemographic composition (e.g., race, class position), social processes or mechanisms provide accounts of how neighborhoods bring about a change in a given phenomenon of interest (Sorensen 1998, p. 240). (447)

A more recent contribution from Sampson appears in the Demeulenaere volume discussed in several earlier posts, Analytical Sociology and Social Mechanisms.  The essay is called "Neighborhood effects, causal mechanisms and the social structure of the city," and it makes an explicit attempt to line up the neighborhood-effect literature with some of the issues of analytical sociology.  Most important is the fact that neighborhood effects are thought to be "emergent" or autonomous with respect to the individual characteristics of the people who make up the population.

Sampson's effort in this essay is to give a satisfactory definition of "neighborhood," to indicate some ways of measuring or describing neighborhood-level properties (what he refers to as "ecometrics", in analogy with "psychometrics"), and to reflect on some possible mechanisms that might work from this level of analysis to the individual level of the people who make up the neighborhood.

Here is how Sampson characterizes "neighborhood" in this piece:

I begin with a general definition of neighborhood as a variably interacting population of people and institutions in a common place. Neighborhoods form a mosaic of overlapping ecological units (e.g. blocks, streets) that vary in size, boundaries and social organizational features. (228-229) 

It is the intersection of practices and social meanings with spatial context that is at the root of neighborhood effects. (230)

And he offers a somewhat different definition of social mechanism from those provided in the existing literature:

I conceptualize a social mechanism as a plausible contextual process that accounts for a given phenomenon, in the ideal case linking putative causes and effects. (230)

Sampson has quite a bit of interesting perspective on the topic of "levels" of social analysis and social causation.  Neighborhood effects are fairly proximate -- local social facts influencing local individual behavior. But Sampson believes that there are plausible mechanisms linking much more distant social conditions or circumstances to the local level as well. For example:

It is not just city-level processes that are at stake -- national and global forces can influence place stratification…. How do we go about documenting the extra-local layers of this kind of "macro-level" neighborhood effect?  … Even calls for analytical sociology are not terribly helpful, focused as they are on the relation of micro and macro (in this case neighborhood) levels, as opposed to higher order structures. What is needed is a truly systemic approach that seeks to theorize and study empirically the "articulation" function of the local community vis-a-vis the larger social world -- how organizations and social networks differentially connect local residents to the cross-cutting institutions that organize much of modern economic, political and social life. (235)

Sampson explicitly parts company with "Coleman's boat", offering a multi-level and multi-dimensional causal model of "neighborhood structure, social-spatial mechanisms, and crime rates" (Figure 11.1; 236).

Unlike most research intentions on neighborhood effects to claim a hierarchical or "top down" primacy of neighborhoods over the individual, I have considered "side to side," "bottom up" and "bird's eye" orientations along with issues of measurement, social causality, methodological individualism, extra-local spatial processes, percepts as causation, and selection bias all as a way to address what I consider a modified analytic sociology "Coleman project". (244) 

Despite the real promise of analytical sociology, I conclude that methodological individualism would do well to grant social context and macro-level factors an equal forum in theories of neighborhood effects. (245) 

Ultimately, then, higher-order processes that induce structure at the neighborhood level require a different way of thinking than the individualist and largely micro-level approaches of existing experimental paradigms. (245)

Sampson's work, with a handful of different collaborators, is a very impressive example of the possibility of bringing together very rigorous quantitative methods with a social realist's interest in causal mechanisms and a non-reductionist's willingness to assign causal powers to supra-individual structures and conditions.  The systematic effort to introduce methods for observing and measuring "neighborhood-level" characteristics -- what they call ecometrics -- is a valuable addition to the toolbox for sociological analysis at a range of levels of social activity.

I'm looking forward to reading Sampson's very interesting forthcoming book, Great American City: Chicago and the Enduring Neighborhood Effect. The book should be available later this month.

(Incidentally, I find it interesting that Sampson highlights some of the same difficulties of defining a concept like "neighborhood" that I discussed in an earlier post on definitions in social theory (228-229); link. Here is a particularly apt statement: "I thus define neighborhoods geographically and leave the nature and extent of social relations problematic. This conceptualization opens the door for empirical research to proceed without tautology and a menu of ecological units of analysis from which to choose depending on the theoretical constructs or social phenomenon under study" (229).)

Microfoundations and meso causation

I take the view that social causation requires microfoundations. And I hold that meso causal explanations are legitimate. How are these two views compatible?

The key is the role that we expect reasoning about micro-level events to play in the explanation itself. The various versions of methodological individualism -- microeconomics, analytical sociology, Elster's theories of explanation, and the model of Coleman's boat -- presume that explanation needs to invoke the story of the micro level events as part of the explanation. The microfoundations-meso explanation perspective requires that we be confident that these micro-level events exist and work to compose the meso level; but it does not require that the causal argument incorporates a reconstruction of the pathway through the individual level in order to have a satisfactory explanation.

Putting the methodological individualist model of explanation crudely, we get something like this:

Institution {I} shapes individuals' desires, beliefs, and passions {Ai}; individuals with these features of agency constitute the micro level; the tools of game theory, agent-based modeling, microeconomics, etc., allow us to aggregate the behavior of these individuals back to the macro level, in a new state of the macro level {O}.

The" meso-causal with microfoundations" view goes something like this.

Institution {I} has causal power P to influence future states of social aggregates; {I} occurs leading to P.
And, outside the explanation itself, we have:
[Institution I's causal powers have micro foundations along these lines: ...]

So when Michael Mann describes the effects of paramilitary organizations in Germany in the 1920s, he relies on a number of assertions about the causal powers of these organizations when introduced into the social circumstances of the 1920s. He is prepared to say how these effects work--so he satisfies the microfoundations requirement. But his explanation is a meso-level one, proceeding from the meso-level causal properties of paramilitary organizations to another set of meso-level effects (link).

When we explain why the tea kettle begins to whistle, we provide a meso-level explanation and we recognize the microfoundations that each step rests upon:

The kettle is filled with water.
The kettle is subject to a hot flame.
Water boils at 100 degrees centigrade.
Steam is produced at higher pressure than one atmosphere.
Steam exits through the spout, creating the whistle.

This is a meso level physical explanation with very well understood microfoundations, at the level of the molecular properties of H2O, its phase transitions, etc. And, of course, that molecular explanation itself has microfoundations. But here is the key point: the explanation at the level of heat, liquid, boiling point, and steam is perfectly satisfactory for many purposes. And it is scientifically satisfactory because we are confident that we understand the micro mechanisms that underlie each step of the argument. But we are not obliged to provide a molecule-level simulation of the situation in order to be satisfied that we have explained the whistling tea kettle.

Working sociologists offer explanations like Mann's on a regular basis. They identify what they take to be causal properties of social structures and institutions, and then draw out causal chains involving those causal properties. And often they are able to answer the follow-on question: how does that causal power work, in approximate terms, at the micro level? But answering that question is not an essential part of their argument. They do not in fact attempt to work through the agent-based simulation that would validate their general view about how the processes work at the lower level.

This account suggests an alternative diagram to Coleman's boat.



The diagram represents the meso-level claim that E1 and E3 jointly cause the occurrence of E2. The meso causal relation is represented as a single-directional orange arrow. The green arrows represent the microfoundations of each meso factor. These causal relations are bidirectional: individual actors are influenced by the meso factor, and their actions have influences on the meso factor. The yellow arrows, finally, represent inter-actor influences at the micro level: network relationships, alliances, communications channels, exemplary behavior, mobilization efforts, etc.

The diagram represents each of the causal linkages represented in the Coleman boat. But it calls out the meso-meso causal connection that Coleman prohibits in his analysis. And it replaces the idea that causation proceeds through the individual level, with the idea that each meso level factor has a set of actor-level microfoundations. But this is an ontological fact, not a prescription on explanation.

And, finally, it is self-evident that we can always ask a different question that looks more like Coleman's: how does the causal property of the meso factor work at the level of the actor? But this is a different question, and we aren't required to incorporate the resulting story into the meso-meso explanation.

Recent thinking about scientific explanation

What do we want from a scientific explanation?  Is there a single answer to this question, or is the field of explanation fundamentally heterogeneous, perhaps by discipline or by research community? Do biologists explain outcomes differently from physicists or sociologists? Is a good explanation within the Anglo-American traditions of science also a good explanation in the German or Chinese research communities? Is the idea of a scientific explanation paradigm-dependent?

For several decades in the twentieth century there was a dominant answer to this question, that was an outgrowth of the tradition of logical positivism and examples from the natural sciences. This theory of explanation focused on the idea of subsumption of an event or regularity under a higher-level set of laws. The deductive-nomological theory of explanation specified that an outcome is explained when we have produced a deductively valid argument with premises that include at least one general law and that lead to a description of the event as conclusion. Carl Hempel was the most prominent advocate for this theory (Aspects of Scientific Explanation), but it was widely accepted throughout the philosophy of science in the 1950s and 1960s.  The "covering law" model was a core dogma for the philosophy of science for several decades.

The D-N theory was subject to many kinds of criticisms, including the obvious point that much explanation involves phenomena that are probabilistic rather than deterministic.  Hempel introduced the inductive version of the D-N model to cover probabilistic-statistical explanation, along these lines. An argument provides a scientific explanation of E if it provides at least one probabilistic law and a set of background conditions such that, given the law and conditions, E is highly probable.  This model was described as the "Inductive-Statistical" model (I-S model).  Wesley Salmon's Scientific Explanation and the Causal Structure of the World falls within this tradition but offers important refinements, including his formal definition of causal relevance.

In each case the motivation for the theory of explanation is a plausible one: we explain an event when we show how it was necessary [or highly probable] in the circumstances, given existing conditions and relevant laws of nature. On the logical positivist approach, an explanation is an answer to a "why necessary" question: why did this event occur? In this conception of explanation the idea of necessity or probability is replaced with the idea of deductive or inductive derivability -- a syntactic relationship among sets of sentences.

A different approach to explanation turns to the idea of causation.  We provide an explanation of an event or pattern when we succeed in identifying the causal conditions and events that brought it about.  This approach can be tied to the D-N approach, if we believe that all causal relations are the manifestation of strict or probabilistic causal regularities.  But not all D-N explanations are causal, and not all causal explanations invoke regularities.  Derivability is no longer the criterion of explanatory success, and explanation is no longer primarily a syntactic relation between sets of sentences.  Instead, substantive theories of causal powers and properties are the foundation of scientific explanation.  A leading exponent of this view is Rom Harré in Harré and Madden, Causal Powers: Theory of Natural Necessity. Nancy Cartwright's Nature's Capacities and Their Measurements is also an important contribution to this view.  And J. L. Mackie's The Cement of the Universe: A Study of Causation is an important contribution as well.  The causal approach retains the idea that explanation involves showing why an event is necessary or probable, but it turns from derivability from statements of laws of nature, to theories of causal powers and properties.

The causal mechanisms approach to explanation continues the insight that explanations involve demonstrating why an event occurred; but this approach moves even farther away from the idea of a causal law, replacing it with the idea of a discrete causal mechanism.  On this approach, we explain an event when we identify a series of causal interactions that lead from some antecedent condition to the outcome of interest.  Hedstrom and Swedborg's Social Mechanisms: An Analytical Approach to Social Theory presents aspects of this theory of explanation in application to the social sciences.  One benefit of the social mechanisms approach is that it also provides a basis for answering "how possible" questions: if our puzzlement is that an outcome has occurred that seems inherently unlikely, we can provide an account of a set of causal mechanisms that transpired to bring it about.

The chief line of dispute in the traditions mentioned so far is between the "general laws" camp and the "causal powers" camp.  Both are committed to the idea that explanation involves showing how an outcome fits into the ways the world works; but the general laws approach presumes that law-like regularities are fundamental, whereas the causal approach presumes that causal powers and mechanisms are fundamental.

So what has developed in the theory of explanation in the past twenty years? Quite a bit. A recent collection of essays coming largely from the Scandinavian tradition of the philosophy of science is quite helpful in orienting readers to recent developments. This is Johannes Persson and Petri Ylikoski's 2007  Rethinking Explanation. Quite a number of the contributions are worth reading carefully.  But Jan Faye's "Pragmatic-Rhetorical Theory of Explanation" is a good place to start.  Faye distinguishes among three basic approaches to the theory of explanation: formal-logical, ontological, and pragmatic.  The formal-logical approach is essentially the H-D and I-S approaches described above.  The ontological approach is the causal-powers approach described above.  The pragmatic approach is in a sense the most important recent contribution to the theory of explanation, and represents a significant re-focusing of the debates in post-empiricist philosophy of science. Here is how Faye describes the pragmatic approach to explanation-theory:

The pragmatic view sees scientific explanations to be basically similar to explanations in everyday life. It regards every explanation as an appropriate answer to an explanation-seeking question, emphasising that the context of the discourse, including the explainer’s interest and background knowledge, determines the appropriate answer. (44)

And why should we consider a pragmatic approach?  Faye offers eight reasons:

First, we have to recognise that even within the natural sciences there exist many different types of accounts, which scientists regard as explanatory. (46)

Second, if one is looking for a prescriptive treatment of explanation, I see no reason why the social sciences and the humanities should be excluded from such a prescription. If they are included, the prescriptive account must include intentional and interpretive explanations, i.e., accounts providing information about either motives or meanings. (47)

Third, the meaning of a why-question alone does not determine whether the answer is relevant or not. (47)

Fourth, John Searle has correctly argued that the meaning of every indicative sentence is context-dependent. He does not deny that many sentences have literal meaning, which is traditionally seen as the semantic content a sentence has independently of any context. (49)

Fifth, many explanations take the form of stories. Arthur Danto has argued that what we want to explain is always a change of some sort. When a change occurs, we have one situation before and another situation after, and the explanation is what connects these two situations. This is the story. (50)

Sixth, a change always takes place in a complex causal field of circumstances each of which is necessary for its occurrence. Writers like P.W. Bridgman, Norwood Russell Hanson, John Mackie, and Bas van Fraassen have all correctly argued that events are enmeshed in a causal network and that it is the salient factors mentioned in an explanation that constitute the causes of that events. (50)

Seventh, the level of explanation depends also on our interest of communication. In science an appropriate nomic or causal account can be given on the basis of different explanatory levels, and which of these levels one selects as informative depends very much on the rhetorical purposes. (51)

Eight, scientific theories are empirically underdetermined by data. It is always possible to develop competing theories that explain things differently and, therefore, it is impossible to set up a crucial experiment that shows which of these theories that yields the correct account of the data available. (52)

Faye then goes on to analyze scientific explanation as a speech act. We need to understand the presuppositions and purposes that the explainer and the listener have, before we can say much about how the explanation works.

Petri Ylikoski's contribution to the volume, "The Idea of Contrastive Explanandum," picks up on one particular but pervasively important feature of the rhetorical situation of explanation, the idea of contrast.  When we ask for an explanation of an outcome, often we are not asking simply why it occurred, but rather why it occurred instead of something else.  And the contrastive condition is crucial.  If we ask "why did the Prussian army win the Franco-Prussian War?", the answer we give will be very different depending on whether we understand the question as:

"Why did the Prussian army [rather than the French army] win the Franco-Prussian War?"

or:

"Why did the Prussian army win [rather than fighting to stalemate] the Franco-Prussian War?"

So scientific explanation is context-dependent in at least this important respect: we need to understand what the question-asker has in mind before we can provide an adequate explanation from his/her point of view. As Henrik Hallsten puts it in his contribution, "What to Ask of an Explanation-Theory",

To summarize: Any explanation-theory must [do] justice to the distinction between objective explanatory relevance and context dependent explanatory relevance or provide good arguments as to why this distinction should not be upheld. (16)

So perhaps the most important recent developments in the theory of scientific explanation fall in a few categories.  First, there has been substantial work on refining the idea of causal explanation (link).  Second, philosophers have reinforced the idea that explanation has pragmatic and rhetorical aspects that cannot be put aside in favor of syntactic and substantive features of explanation. And third, there is more recognition and acceptance of the idea that explanatory models and standards may reasonably differ across disciplines and research areas.  In particular, the social and historical sciences are entitled to offer explanatory frameworks that are well adapted to the particular kinds of why and how questions that are posed in these fields.   In each case the philosophy of science has made a very great deal of progress since the state of the debates about explanation that transpired in the 1960s.

Current issues in causation research

This week's conference on Causality and Explanation in the Sciences in Ghent was an unusually good academic meeting (link). Participants gathered from all over Europe, as well as a few from North America, Australia, and South Africa, to debate the logic and substance of causal interpretations of the world. Among other things, it provided all participants with a very good sense of the ideas about causation that are generating the most discussion today.

A general perception that emerges from the gestalt of papers at the conference is that there are three large focus areas in current research on scientific causation. First, there is interest in specifying what causal assertions and concepts mean in scientific explanations. What are the logical, conceptual, and pragmatic issues associated with causal assertions and explanations?

Second, there is a large body of work focusing on the methods we can use to support causal inference in the sciences. Every field of science produces volumes of data about variables and events over time. What methods exist to permit inferences about causal relationships among the observed variables and entities? This includes causal modeling statistical methods, but also comparative methods deriving from Mill's methods of difference and similarity.

Third, there is a group of philosophers and scientists who are primarily interested in the ontology of causation in various parts of the sciences. How do various factors exercise causal powers in ecology, the social sciences, or complex systems? Researchers in these areas need provisional answers to questions raised by the first two groups, but their focus is on substantive causal processes rather than the logic of causal statements.

It is useful to inventory half a dozen approaches that were repeatedly cited. This survey is impressionistic but gives an idea of the current landscape.

The mechanisms approach. The idea that we can explicate causation through the idea of a mechanism has been rising in importance over the past twenty years. The idea here is that the fundamental causal concept is that of a mechanism through which X brings about or produces Y. This is argued to be key to causation from single-case studies to large statistical studies suggesting a causal relationship between two or more variables. Peter Hedstrom and other exponents of analytical sociology are recent voices for this approach for the social sciences, though expositions of this approach don't usually go into the level of detail expected by philosophers like Woodward and Cartwright. An important paper by Peter Machamer, Lindley Darden and Carl Craver, "Thinking about Mechanisms", sets the terms of current technical discussions; their view is referred to as the MDC theory. A common concern is that the approach hasn't been as clear as it should be about what precisely a mechanism is. James Mahoney made this criticism in 2001 in "Beyond Correlational Analysis" reviewing Charles Ragin, Fuzzy-Set Social Science and Peter Hedstrom and Richard Swedberg, Social Mechanisms: An Analytical Approach to Social Theory (link), and we still need a more generally recognized specification of the idea. (See an earlier post on this approach; link.)

The manipulability account. Jim Woodward is perhaps the leading exponent of the manipulability (or interventionist) account. He develops his views in detail in his recent book, Making Things Happen: A Theory of Causal Explanation. The view is an intuitively plausible one: causal claims have to do with judgments about how the world would be if we altered certain circumstances. If we observe that the concentration of sulphuric acid is increasing in the atmosphere, we might consider the increasing volume of H2SO4 released by coal power plants from 1960 to 1990. And we might speculate that there is a causal connection between these facts. A counterfactual causal statement holds that: If X (increasing emissions) had not occurred, then Y (increasing acid rain) would not have occurred. The manipulability theory adds this point: if we could remove X from the sequence, then we would alter the value of Y. And this in turn makes good sense of the ways in which we design controlled experiments.

Difference-making. Another strand of thinking about causation focuses on the explanations we are looking for when we ask about the cause of some outcome. Here philosophers note that there are vastly many conditions that are causally necessary for an event but do not count as being explanatory. Lee Harvey Oswald was alive when he fired his rifle in Dallas; but this doesn't play an explanatory role in the assassination of Kennedy. Crudely speaking, we want to know which causal factors were salient; which factors made a difference in the outcome. Michael Strevens provides a detailed and innovative explication of this set of intuitions in his recent book Depth: An Account of Scientific Explanation, where he introduces his theory of "Kairetic" explanation.

Contrastive analysis as a theory of explanation. When we seek an explanation of something, we generally have something specific in mind: why X rather than X'? And an explanation that keys off the wrong contrast will fail, even though its premises are correct. Bas van Fraassen (1980), The Scientific Image, is often cited in this context. A conference participant, Petri Ylikoski, develops a contrastive counterfactual theory in his dissertation (link). This body of work seeks to clarify pragmatic issues concerning explanation, including understanding and explanatory relevance. If we ask for an explanation for why X occurred, we are usually presupposing a question like this:

Why did X occur [rather than Y]?

• Why is John carrying his umbrella [rather than not]?
• Why is John carrying his umbrella [rather than his raincoat]?
• Why is John carrying his umbrella [rather than his assistant Harry]?

These all demand different answers:

• Because he expects rain;
• Because it is too warm for a raincoat;
• Because Harry is carrying three heavy suitcases.

Here is a much-cited review article by Nancy Cartwright on van Fraasen's work (link), and here is a discussion of contrastive explanation by Jonathan Schaffer (link).

Causal modeling theory. This topic refers to the large body of statistical theory devoted to identifying potential causal relationships among observable variables in a large data set. Hubert Blalock is a founder of this approach (Causal Inferences in Nonexperimental Research; 1964) with his statistical models for causal path analysis. (Here is a short account of the history of path analysis in genetics.) Judea Pearl has contributed a great deal to the method of structural equation modeling (SEM) in Causality: Models, Reasoning and Inference and elsewhere. Here is a handbook article in which he explains the method and its causal relevance (link). Pearl maintains a research blog on causality here. Granger causality is a specific technique for assessing causal relationships within time series data: X Granger-causes Y if variations in X and Y together do a better job of predicting Y than variations in Y by itself.

Prior foundations of philosophical theories of causation. Two older discussions of causality also received some notice in these papers: J. L. Mackie on INUS conditions and causal fields (The Cement of the Universe: A Study of Causation) and Wesley Salmon on the causal structure of the world (Scientific Explanation and the Causal Structure of the World).

Nancy Cartwright's "Causation: One Word, Many Things" provides a very good contemporary review of the varieties of approaches that are currently being taken to the idea of causation (link).

Much of the intellectual vitality of this group of philosophers is captured in the major work recently edited by Phyllis McKay Illari, Federica Russo, and John Williamson, Causality in the Sciences. The book contains a very wide range of disciplines and approaches in its treatment of the topic.

Social explanation and causal mechanisms

To explain a social outcome or regularity, we need to provide an account of why and how it came about; and this means providing a causal analysis in terms of which the explanandum appears as a result.

Having a causal theory of a realm requires having an ontology: what kinds of things exist in this realm, and how do they work? Along with others, I offer a social ontology grounded in the actions and relations of socially constituted actors, which I refer to as methodological localism (link). (This is also the ontology asserted by the programme of "analytical sociology";  link.)

This entails, basically, that we need to understand all higher-level social entities and processes as being composed of the activities and thoughts of individual agents at a local level of social interaction; we need to be attentive to the pathways of aggregation through which these local-level activities aggregate to higher-level structures; and we need to pay attention to the iterative ways in which higher-level structures shape and influence individual agents.  Social outcomes are invariably constituted by and brought into being by socially constituted, socially situated individual actors (methodological localism). Both aspects of the view are important. By referring to "social constitution" we are invoking the fact that past social arrangements have created the social actor. By referring to "social situatedness" we invoke the idea that existing social practices and rules constrain and motivate the individual actor. So this view is not reductionist, in the sense of aiming to reduce social outcomes to pre-social individual activity.

We also want to refer to supra-individual actors -- firms, agencies, organizations, social movements, states. The social sciences are radically incomplete without such constructs. But all such references are bound by a requirement of microfoundations: if we attribute intentionality to a firm, we need to be able to sketch out an account of how the individuals of the firm are led to act in ways that lead to the postulated decision-making and action (link).

So, then: what is involved in asserting that social circumstance A causally produces social circumstance B? There are, of course, numerous well developed answers to this question: statistical inference based on correlations of occurrences, conditional probabilities, and necessary-sufficient condition analysis. My view, however, is that there is a more basic meaning of causation: A caused B iff there is a sequence of causal mechanisms leading from A to B. This approach is especially suitable for the social realm because, on the one hand, there are few strong statistical regularities among social outcomes, and on the other, it is feasible to identify social mechanisms through a variety of social research methods -- comparative analysis, process tracing, case studies, and the like.

The social mechanisms approach (and the scientific realism that lies behind it) goes back at least as early as the late 1980s. An early statement of the view was presented in my Varieties Of Social Explanation: An Introduction To The Philosophy Of Social Science in 1991.  Mario Bunge and Jon Elster took similar positions. The view took a large step forward, on the theory side, with the publication of Hedstrom and Swedberg's Social Mechanisms: An Analytical Approach to Social Theory (1998), and on the empirical research side with the publication of McAdam, Tarrow, and Tilly's Dynamics of Contention (2001). There are important differences; theorists within analytical sociology largely favor methodological individualism and mechanisms grounded in rational individuals, whereas Tilly and his colleagues favor "relational" mechanisms. But in each case the model of agent-centered explanations that either require microfoundations or are plainly compatible with such a requirement.  (Here is a recent post on causal mechanisms.)

Several social scientists have anticipated this approach through their own concrete analysis of aggregation phenomena.  A good illustration is Thomas Schelling.  His work presents a large number of examples of mundane social outcomes that he explains on the basis of simple individual-level choices and an aggregation mechanism (Micromotives and Macrobehavior, Choice and Consequence). Features of organized crime, traffic patterns, segregation, and dying seminars all come in for treatment.  Schelling demonstrates in concrete terms what sorts of things we can identify as "social mechanisms" and traces them back to the circumstances of action of individuals in social situations.

The framework of social mechanisms as a basis for social explanation raises an important question about the role and scope of generalizability that we expect from a social explanation. Briefly, the mechanisms identified here show a degree of generalizability; as McAdam, Tarrow and Tilly assert, social mechanisms can be expected to recur in other circumstances and times. But the event itself is one-of-a-kind. This is a familiar feature of Tilly's way of thinking about contentious events as well: the American Civil War was a singular historical event. But a good explanation will invoke mechanisms that recur elsewhere. We shouldn't expect to find general theories of civil wars; but our explanations of particular civil wars can invoke quasi-general theories of mid-level mechanisms of conflict and escalation. (Here is a recent posting on general and specific causal claims.)

Another important methodological question for this approach to social explanation is the issue of explaining general statistical patterns in social life.  What if we want to explain something more quantitative -- say a gradually rising divorce rate or the finding that co-habitants before marriage have higher divorce rates than non-co-habitants? On the social mechanisms approach, we would want two things. First, we would like an agent-level mechanism that explains the statistic; and second, we would like to find a common cause if the phenomenon is similar in several countries.

Finally, the actor-based mechanisms approach invites an area of study which is now being referred to as "aggregation dynamics" (link, link).  We need to have theories and tools that permit us to aggregate different micro-level processes over time into meso- and macro-outcomes, taking into account the complexity of causal interactions in a dynamic process.  The tools of agent-based modeling are relevant here (link).

Spartacus, Kitty Genovese, and social explanation

What is most interesting in paying attention to social life is noticing the surprising outcomes that often materialize from a number of uncoordinated choices and actions by independent individuals. We want to understand why and how the aggregate-level social fact came to be: was it a set of features of the individual actors' preferences or decision-making?  Was it the unintended result of strategic choices by various actors?  Was it simply the path-dependent and contingent outcome of a serial interactive process?  Was it brought about by structural conditions -- power, wealth, race -- within the context of which actors made their choices?  And what were the mechanisms of constraint, aggregation, contagion, and escalation through which actions and processes at the more proximate level came together into the outcome at the distal level?

Consider a pair of examples. Kitty Genovese is attacked by an assailant over an extended period of time in a dense neighborhood in Queens, many people observe the crime, and no one intervenes.  The woman is eventually murdered.  The question here is, why was there a total absence of intervention by any individual or group in this crime?  And a parallel surprise: General Marcus Licinius Crassus, having trapped the rebellious slave army of Spartacus, announces that the slaves will be spared death if they give up Spartacus for crucifiction.  Spartacus rises to his feet to say, "I am Spartacus." And in minutes the army of men rise as well, all declaring "I am Spartacus."  Here the question is the reverse: why do these men expose themselves to death to stand in solidarity with Spartacus?  In each case, there is an occasion for action presented to a group of individuals, in which members of the group can attempt to save the life of another person.  The collective behavior is fundamentally different in the two cases.   Why so? What are the mechanisms, psychological and social, that led to non-intervention in the first case and fatal solidarity in the second?

We might form a number of hypotheses about both of these cases in order to explain the very different outcomes.  In the Kitty Genovese case, we might cite anomy and anonymity as possible causes of the lack of response by bystanders.  With a low level of civic bonds, perhaps city dwellers have such a low level of emotional involvement with each other that even the slightest effort is unjustified.  Or perhaps it is the fact that each potential responder is anonymous to the others that leads to the result; he/she can make the decision to refrain from offering aid without fear of criticism from others.  Or perhaps collective behavior is strongly influenced by the actions of the first few, with later observers mimicking earlier non-aiders.  So the outcome might have been highly different if the first or second witness had intervened; others might have followed suit.   In the case of Spartacus, we might hypothesize that the bonds of solidarity forged by a history of fighting the Roman army gave the soldiers the moral motivation to support Spartacus; or perhaps it is the publicity of the scene, or the early example of the first few supporters, that spread to the behavior of the others.  Or perhaps it is an expression of fundamental mistrust by the soldiers of the good faith of Marcus Crassus; "he will kill us anyway." With nothing to lose, the army makes its symbolic statement of rejection.  These are each social psychological hypotheses, concerning the ways that individuals choose to involve themselves in an emergency and a situation of potential sacrifice.

Each of these hypotheses represents a social mechanism that can be incorporated into a narrative explaining the aggregate outcome.  In order for such a story to be scientifically compelling, we need to have some way of using empirical evidence to evaluate whether the postulated mechanism actually works in the real world of human behavior.  Is there empirical evidence for a social psychology of mimicry?  Do we have evidence to suggest that members of a crowd are more likely to do X or Y if a few others have already done so?  Is there empirical support for a theory of solidarity as a social motivation: do combat teams, groups of deep-ground miners, or emergency room doctors develop a higher willingness to conform their behavior to the good of the group or of other individuals in the group?  These examples of social mechanisms all fall in the category of putative behavioral regularities, and it should be possible to investigate them experimentally and statistically.

The challenge of explanation for any social outcome, we might say, is that of constructing an interpretation of the states of minds of a set of actors; the constraints and opportunities within which they choose a course of action; and the interactions that are created as they act within a common environment, leading to the outcome in question.  This is what we can refer to as an aggregative explanation, and it lies at the heart of Thomas Schelling's methodology in Micromotives and Macrobehavior.  As Schelling points out, sometimes the explanation turns on specific features of agency (the actors' preferences or their modes of decision-making), and sometimes it turns on the specifics of the environment of choice (the fact that the outcome of action is a public good).  But in general, explanation proceeds by showing how agents with specific features, acting within a social and natural environment with specific characteristics, bring about specific kinds of outcomes.

This, in a nutshell, represents a simple but powerful statement of a philosophy of social explanation.  It also represents the rudiments of a social ontology: higher-level social features are composed of the actions and states of agency of a set of actors within the context of locally embodied rules, norms, and expectations.  This is what I refer to as "methodological localism":

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 rule. (link)

Social explanations derive their force from empirical research into the nature of the actor, the nature of the locally embodied social environment, and the processes of aggregation through which actions by multiple actors coalesce into social outcomes.  The explanation satisfies us when it demonstrates the pathways through which individuals, constituted as they are found to be, located in institutions of the sort described, contribute to collective outcomes of the kinds described.