Historical comparisons

Historians are sometimes interested in comparing two cases or events in order to discover something of historical importance -- common causal mechanisms, important institutional differences between the cases, or ways in which the cases illustrate some larger historical pattern. For example, Kenneth Pomeranz offers an extensive comparison of European and Asian economic development in The Great Divergence: China, Europe, and the Making of the Modern World Economy. Other examples of historical comparisons might include the Russian Revolution and the Chinese Revolution; the build-out of railroads in Britain versus France; the collapse of the French Army in 1870 versus 1940; the colonial experience in Senegal versus Kenya; the development of London versus Tokyo; and many others.

The question to be considered here is this: what standards or heuristics ought to govern the choice and definition of units of comparison? Would it make sense to compare World War II with the war in Bosnia? Or the scientific cultures of Bologna in 1400 with that of London in 1960? Or the Spanish Civil War with the culture clash of the United States in the 1960s? What factors make for a historically insightful comparison?

Part of an answer is obvious at the start: there is no hard-and-fast answer to the question. It is always possible that there is a basis of comparison across apparently radically dissimilar cases. So the Spanish Civil War comparison with Madison SDS activism might seem to single out two cases that are too incommensurable to be valuable -- until a creative historian notices that each historical moment revealed deeply different political and moral worldviews and that these ideological differences led to substantial inter-group hostility and conflict in each case. And this comparison might then lead this historian to ask the productive question: why did one instance result in years of warfare and the second resolved into peaceful protest?

Further, it is evident that comparison depends upon the background set of questions that we want to answer; useful comparison is topic-dependent. Comparing Bologna 1400 with London 1960 might be useful if we are investigating the cultural transmission of ideas but useless if we are investigating the causes of urban unrest. And comparing Paris 2006 with Detroit 1967 might be valuable on the second topic but beside the point for the first.

Historically insightful comparison also requires that we not be dazzled by the fact that similar language is used to describe or categorize multiple events. The Chinese Revolution and the Russian Revolution might be described in very similar terms: revolutions resulting from the overthrow of a pre-modern state by a militant party of revolutionaries leading an emerging under-class population. But this description is misleading on its face and in what it conceals. These historical events were actually very different in their political composition, the role and behavior of parties, and the relations that existed among other social forces. The Russian Revolution might be re-described as an opportunistic seizure of power by a minor political party, and the Chinese Revolution might be described as a long, slow mobilization of a mass population in support of revolutionary change. Other descriptions are possible as well. The point is that the common label of "revolution" should not mask the possibility or likelihood of extreme differences in processes, politics, parties, and mobilizations in the two instances.

To get some guidance, we need first to reflect on what the goal of the comparison is. And there are numerous goals that a historian might have. For example --

• discover "generalizations" about similar processes. ("Each of the revolutions studied contains "state crisis" as a causally necessary factor.")
  
• identify concrete historical mechanisms that are at work in the cases -- whether or not they recur in other cases as well. ("Political mobilization in the first case proceeds through pre-existing religious organizations on the ground; in the second case it proceeds through control of the national media.")
  
• identify causally salient differences across cases that explain divergence of outcomes. (Here the idea would be an argument something like this: cases A and B are similar in many ways. However, A leads to X, while B leads to Y. What explains this divergence of outcome?)
  
• discover some of the substantial variety that exists underneath the surface in events that seem superficially similar. (We might pursue this "difference" strategy in urban history and choose a set of examples that will illustrate the many ways in which the world's cities have evolved and are organized and governed.)

Thus the selection of cases will depend on what the purpose of the comparison is. But in general, the only reason to engage in comparison is the likelihood that we will learn something from the comparison that we would not have learned from study of one of the individual cases.

All this said -- we might consider the heuristic that says that the cases need to be similar enough to permit comparison in terms of structures, processes, and causes; different enough to invite inquiry about the causes of the differences; and integrated enough to allow us to say that this level of unit of analysis possesses the complex set of historical characteristcs under study as a whole.

Let's flesh this heuristic prescription out by considering one specific historical question: How did "European economic development" compare with "Asian economic development"? Before we can begin to try to answer this question, we need to give a more thoughtful definition of the units of comparison. Should the comparison be between continents, between countries, between regions within countries, or between selected cities and villages? Kenneth Pomeranz and others argue that continents and nations are too large to serve as a basis of valuable economic comparison, in a very specific sense: they encompass too much variety of social and economic processes to permit valid comparison. Pomeranz argues instead that Eurasian comparison is most valid if we select integrated economic regions of roughly comparable size; large enough to encompass the range of economic, social, and political arrangements that plausibly influence economic development, but not so large that the scale obliterates distinctive patterns and outcomes. Based on these sorts of considerations, he argues that it is most useful to consider a comparison between the core economic regions of England and the Lower Yangzi Delta in China. (James Lee offers an even more disaggregated basis for comparison of demographic regimes; he argues for a comparison based on descriptions of populations at the community level, ignoring nations and large economic regions altogether; Life Under Pressure: Mortality and Living Standards in Europe and Asia, 1700-1900.)

(See Eurasian Historical Comparisons for more on one aspect of this issue.)

Is it an interesting sociological fact that "urban people are better educated than rural people"?

Let's suppose that this statement about urban-rural differences in educational levels summarizes census data by calculating the average number of years of formal schooling for people in cities and people in rural areas. Is this brute fact about two large populations a valid description of the two populations? Is it an important or illuminating sociological fact?

There are several types of questions we need to ask about this fact. First, there are questions to address about the statistical features of the data themselves. How are these two populations distributed around the mean? How wide is the variance around the mean? Do we get a different result if we measure the median number of years of schooling as opposed to the mean? Which of these measures is a more meaningful description of the population as a whole -- median or mean?

Consider a hypothetical set of results. If the rural population is quite homogeneous around a mean of 10 years of schooling, while the urban population is widely distributed in a range from 5 years to 20 years, the fact that the urban mean is 11 years is somewhat misleading; the majority of urban people in this hypothetical case have less than 9 years (so urban is less well educated), while at the same time 20 percent of urban people have at least 14 years (so urban population is better educated). The point is this: the brute fact of a difference in the means is not particularly insightful in estimating the educational resources of the two populations.

Second, there are important sociological questions about the internal differentiation of the population into groups with very different educational patterns. Do women and men show different profiles in the two large populations? How about members of ethnic or racial groups? How about groups identified by income, wealth, or home ownership? What about groups defined by whether a parent had attended college? Arriving at this set of questions requires sociological imagination. The investigator needs to consider what internal differentiations within the large population might affect the sub-group's educational characteristics.

Finally there is the question of finding possible causal explanations of the differences that are discovered across major populations (urban and rural) and within sub-populations (ethnic, gender, or class-defined groups), and tracing out some of the ways in which these patterns in turn cause other social outcomes (future inequalities of income, for example). Those causal mechanisms might be various: differences in the opportunities that are presented to members of different social groups (including the possibility of discrimination), differences in values and cultures, within families, differences in gender treatment, differences in religious traditions and practices, and differences in access to resources, to name a few.

Now suppose we have done quite a bit of empirical, theoretical, and causal analysis along these lines. Suppose we have found that the internal structures of eduational attainment statistics are quite different between urban and rural populations; that the taxonomy of sub-groups is different; and that the causes and social mechanisms of the differences in attainment across the rural-urban divide are substantially different as well. What salience does the original brute fact continue to have (that the means are different in the two populations)?

We might say that the brute fact is in fact a valid empirical observation; that it needs to be substantially further analyzed; and that the genuinely valuable and insightful sociological findings only emerge once we have further disaggregated the statistics across salient groups and have provided some hypotheses about the mechanisms that influence the educational attainment profiles of the various sub-groups. At that point we have some idea of the underlying sociology that produces the brute fact. But the brute fact itself is largely unilluminating.

Does historical materialism have a place in today's social sciences?

Marx's theory of historical materialism came with a few central concepts, a large hypothesis, and a heuristic for social research. The concepts include class, the forces and relations of production, the economic structure, the superstructure, and the idea of determination ("in the last instance", as Althusser and Poulantzas put it) between the economic structure and elements of the superstructure. The heuristic is, "Look to the circumstances of property and class -- the material circumstances of society -- in order to discover the causal relationships that exist in large social change across history." The large hypothesis is that the historical dynamic created by tension between the forces of production (the level of technology and labor skills) and the relations of production (the property relations) creates a set of imperatives and constraints for social change that leads to the formation and transformation of other social elements, such as the state, morality, or culture. Class and class conflict play a central role in mediating the effects of the economic structure on other aspects of society.

Are these elements of historical materialism still of value to sociology and historical explanation?

The concepts associated with the theory of historical materialism are legitimate macro-sociological tools for organizing and analyzing social institutions and structures within particular societies. Their utility depends on the degree to which they permit the historian to identify and explain in detail the real social processes that are underway in the society under examination. There is no a priori basis for judging that this conceptual scheme is superior to other alternatives (as Marx sometimes seems to suggest). Rather, we need to evaluate the materialist conceptual scheme through its fecundity in identifying causal mechanisms and processes within the empirical phenomena under study.

The heuristic too remains insightful -- as long as we keep in mind the fact that historical change has many causes. It is fair to say that material factors have historical influence -- levels of technology influence other social institutions such as the educational system, the property system creates a set of interests that have important political effects on mobilization, and struggle over the control of social wealth is plainly an important historical factor. And it is a productive strategy for historians to examine in details the ways in which material circumstances produce other kinds of social change through the actions of historically situated actors. Further, careful study of the material circumstances of a society shed important light on the circumstances of life for the almost invisible ordinary people.

The master hypothesis of historical materialism is the least enduring. Marx's reading of history within the lenses of historical materialism was simply too deterministic, too unidirectional, and too single-factored, to provide a credible basis for explaining historical change. The difficulty with the hypothesis is its comprehensiveness and its suggestion that there is only one major historical dynamic. But take any particular historical outcome of interest -- the dynamics leading to a rebellion in North China, for example. Material conflicts of interest are likely enough to be part of the motivations of the participants, and the powers associated with various groups derivative from their control of wealth and property are plausibly related to the ability of various groups to play an influential role in the developing events. However, there are plainly other social and causal factors that are unrelated to the property system -- for example, a history of drought or flooding in the region, the structure and tenacity of kinship systems, the nature of local morality and justice sensibilities, the degree of transportation interconnectedness of the region, and indefinitely many other factors.

It is implausible, then, to suppose that a single factor -- whether material class circumstances, ideology, or other social characteristics -- is the sole important causal factor in large historical processes. Historical processes are contingent and conjunctural, so the effort to discover a single key to explain all large historical processes and outcomes is futile. At the same time, it is plausible enough that the circumstances and institutions associated with technology and property have historical effects; and in fact, it is straightforward to describe the microfoundations through which these institutions interact with ordinary human behavior and choice to lead to social outcomes. This assessment suggests that historians and sociologists are well justified in including the concepts and heuristics of historical materialism in their tool kit, but that they would be well advised to reject the almost metaphysical certainty of the grand hypothesis.

(See Gerald Cohen, Karl Marx's Theory of History, for an analytic philosopher's pathbreaking treatment of historical materialism.)

How not to create a classification system

Does social science require systems of classification?

From Jorge Luis Borges' description of a fictional Chinese classification of animals:

“These ambiguities, redundancies and deficiencies remind us of those which doctor Franz Kuhn attributes to a certain Chinese encyclopaedia entitled 'Celestial Empire of benevolent Knowledge'. In its remote pages it is written that the animals are divided into: (a) belonging to the emperor, (b) embalmed, (c) tame, (d) sucking pigs, (e) sirens, (f) fabulous, (g) stray dogs, (h) included in the present classification, (i) frenzied, (j) innumerable, (k) drawn with a very fine camelhair brush, (l) et cetera, (m) having just broken the water pitcher, (n) that from a long way off look like flies.” Jorge Luis Borges, Other Inquisitions: 1937-1952

The lesson? That a system of classification needs to rest upon a coherent, logical assessment of the causal and structural properties of the things being classified, so that the classification may lead us to a better understanding of the range of phenomena encompassed by the system.

The social science disciplines

The social sciences consist of a variety of disciplines, subject areas, and methods, and there is no reason to expect that these disciplines will eventually add up to a single unified theory of society. Political science, sociology, history, anthropology, economics, geography, and area studies all provide their own, largely independent, definitions of scope, research agenda, and research methods. And there is no grand plan according to which the disciplinary definitions jointly capture all that is of scientific interest about the social.

History rather than logic explains the particular configuration of social science disciplines that we now face. The major social science disciplines have grown up in the past century and a half by creating stylized answers to these topic areas: the “political” concerns institutions of coercion and governance; the “economic” has to do with production, exchange, and distribution of goods and services; the “anthropological” has to do with the cultures, values, and practices through which individuals and groups conduct their local lives. Area studies are defined according to a different axis; Asian studies or Latin American studies demand that we cut the social differently: not from the point of view of social domains, but from the point of view of geographical complexes of related social, cultural, economic, political, and normative regimes.

At the same time, we as “users” of the results of social inquiry have no inherent interest in the intra- and inter-disciplinary debates that have led to the constitution of the disciplines of the social sciences as they currently exist. The social world does not come to us labeled as “political,” “economic,” or “ethnographic.” We ordinary citizens have questions that cut across these boundaries recklessly: Why does the US state so commonly ignore the needs of poor people? Why are Indonesian rice farmers reluctant to make use of HYV rice strains? Why did the hi-tech bubble occur in the American economy in the 1990s? How do police departments succeed in recruiting good potential officers? When is the practice of charitable giving most likely to thrive or falter? Why did the Chinese Communist revolution occur? Why did it succeed? Note what a mixture of topics, human interactions, and methodologies is invoked by this collection of questions. Some of these queries raise the question of why individuals behaved as they did; some focus on group action, while others single out individual choices; some have to do with the institutions within which individuals live; some suggest turning to ethnography, comparative economics, or political science; and so forth.

The upshot is this: Users of the social sciences have a different way of parsing “the social” than is found in academic social science. We are interested in human agency and behavior — individual and collective. We are interested in the ways social relations and institutions work, and how they affect the behavior and choices of the individuals who operate within them. We are interested in how large agglomerations of human activity work — how they emerge, how they behave over time, and how they go wrong (cities, states, corporations, networks of friends, …), and we are interested in the dynamics of face-to-face social interaction.

This suggests that new thinking about the social sciences needs to start with the idea of acquiring a strong commitment to interdisciplinary study of common social topics.

(Here are several other posts on "social science disciplines" (tag).)

What kind of knowledge can philosophy offer?

Let us say that knowledge is "a set of true statements based on compelling reasons." (This is the same as the familiar definition of knowledge as "justified true belief".) Philosophers offer a variety of claims, and they offer arguments for their positions. But do they offer knowledge about anything? Is it possible to say that "Philosophical statement P is true", or only that "Philosophical statement P is supported by strong and compelling reasons"? Are philosophical topics within the domain of things concerning which we can have knowledge at all?

We know what kind of knowledge empirical science provides: factual knowledge about the world and inferences or theories supported by empirical observation. We also know what kind of knowledge is offered by mathematics and logic : deductive knowledge derived from a set of axioms in one or another of the fields of mathematics. And we can specify the nature of the knowledge provided by linguistics and semantics: expository knowledge of the meanings of various words and phrases in ordinary usage. Putting these areas of inquiry very crudely, we might summarize them as "inductive knowledge," "deductive knowledge," and "semantic knowledge." But what does philosophy add to our knowledge and understanding of human experience and knowledge?

Notice that knowledge and truth are interrelated. Truth, in turn, has to do with correspondence and reference. Statements refer to things and properties; statements are true or false depending on whether the things to which the statement refers in fact possesses the properties attributed to it. So a statement cannot be a piece of knowledge if it does not permit of correspondence to some independent set of facts.

Now consider the kinds of reasoning and statements that occur within philosophy.

First, philosophy offers assertions based on rigorous analysis of concepts and conceptual relationships. This exercise looks a bit like the linguistics/ semantics option above; but philosophers offer "value-added" by providing rational reconstruction of the concepts they consider. They reconstruct and improve upon the concepts of everyday language.

Second, philosophy may provide constructive analysis and further development of the methods and conceptual systems of various disciplines, including the empirical sciences. Here the philosopher is purporting to offer substantial findings that will improve upon the epistemic characteristics of existing scientific practices. Crudely, a deeper understanding of the logic of evolutionary explanation and the mathematics of natural selection is a philosophical effort, and it is a substantive contribution to the philosophy of biology and to biological theory. Here, we must ask whether there is a credible basis for the contribution. In what respect does the philosopher possess a distinctive basis for providing rational assessment and recommendations about the structure and practice of empirical science? Typically, philosophers would respond by saying that philosophical argumentation about the methods of science gains credibility through the understanding of rationality and reasoning that philosophers possess.

Third, philosophy can construct ethical theories that possess some degree of justification, beyond ordinary moral opinions. When John Rawls asks, "What is justice?", he begins with some ordinary associations with the concept, but then builds out a theory of justice that goes far beyond ordinary language. And he offers a range of philosophical justifications in support of his theory of "justice as fairness".

A major problem in answering the key question, what is the nature of philosophical knowledge, is the fact that we ordinarily divide knowledge into "empirical/contingent" and "formal/necessary" (or what Quine calls the "analytic/synthetic" distinction). But philosophers seem to advance their theories in a way that implies they are neither empirical nor purely formal. Kant puts this point in the form of a category of knowledge that is "synthetic a priori" -- that is, knowledge that is based on purely philosophical reasoning but that is nonetheless not purely formal. (Kant's claim that the statement "reality is spatially organized in Euclidean three-dimensional space" is true synthetic a priori asserts that the statement is necessarily true but is not a truth of logic.)

One possible stance that we might take is to restrict the concept of "knowledge" to statements about empirical states of affairs (where truth and falsity are possible), but to then postulate other categories of belief that have a degree of rational credibility without correspondence to the empirical world. On this approach, empirical statements, suitably supported, can constitute knowledge of the empirical world. Philosophical statements -- statements about scientific method, the nature of beauty, or ethical principles -- can be offered with rational justification but do not have the referential structure that would permit them to be "true" and do not count as knowledge. If we take this approach, then we may be justified in accepting the proposition "Justice is fairness," but we would not be justified in thinking it is "true." And therefore the statement is not an example of "knowledge".

This approach sounds a bit parallel to the position of early twentieth-century logical positivism, which maintained the verificationist theory of meaning -- the meaning of a sentence is the set of conditions that establish its truth or falsity -- with the result that theology, philosophy, or ethics are strictly speaking meaningless. However, the two views are not the same, because this view permits that philosophical discourse is meaningful and rational; it simply denies that the statements that philosophers make either correspond or fail to correspond with facts about the world.

The conclusion to this line of thought is somewhat startling: philosophy does not offer knowledge at all. However, it does provide opinions and statements that are founded on good reasons, and we have rational grounds for believing these statements.

What is a social structure?

Are there such things as "social structures"? In what do they consist? What sorts of social powers do they exercise? This is a question I considered in greater detail in New Contributions to the Philosophy of History and Varieties of Social Explanation. But it is worth taking up here as well.

Here are a few books that have made useful contributions to the current understanding of the causal powers of social structures.



Consider a few candidates for social structures: the global trading system, the Federal government, the Chinese peasantry of the 1930s, the English class system, the Indian marriage system, race in the United States, the city of Chicago. Are these items examples of "social structures"?

What are the central assumptions we make in designating something as a social structure? (Note that the term "social structure" can be used in at least two important senses: first, as a causally operative institutional complex (the state or the market as causal social structures), and second, as a description of facets of the organization of society (demographic structure, urban-rural structure, structure of race and ethnicity, income structure). Here I will focus on the first sense of the term.)

Several ideas appear to be core features in our ordinary understanding of this concept. A social structure consists of rules, institutions, and practices. A social structure is socially embodied in the actions, thoughts, beliefs, and durable dispositions of individual human beings. A social structure is effective in organizing behavior of large numbers of actors. A structure is coercive of individual and group behavior. A social structure assigns roles and powers to individual actors. A social structure often has distributive consequences for individuals and groups. A social structure is geographically dispersed. Social structures can cause social outcomes involving both persistence and change.

We might try to reduce these intuitions to a definition: a social structure is a system of geographically dispersed rules and practices that influence the actions and outcomes of large numbers of social actors.

Now back to our original question: do such things exist? Before proceeding to a answer, a few points are evident. Any social entity must possess microfoundations in human mentalities and actions. There is no such thing as a social entity that lacks human embodiment--any more than there are works of art that lacks material embodiment. Social entities "supervene" upon human individuals.

This point also applies to any statements we might make about the putative causal powers of a social entity. So claims about the causal properties of social structures must be supplemented by a theory of the microfoundations of those powers. How does an extended social structure exert influence over the actions of located individuals?

And there is a final parallel point about claims about the geographical scope and coherence of a social entity. If we want to maintain that an entity exercises influence as a coherent and extended entity, we need to be able to specify the mechanisms through which this takes place. How does the Federal state exert its control and influence over the vast scope of the United States and its population?

So, with these qualifications about the unavoidable need for providing microfoundations--are there social structures?

Several of the instances offered above fit the terms of our provisional definition. They are large complexes of rules and practices that influence behavior and outcomes. And it is straightforward to begin to provide a description of the microfoundations upon which they exist: the social components through which these structures are embodied and through which they exercise influence on individuals and groups. The US Federal Government functions as a system of branches of government, each with its own departments governed by formal and informal rules. And the "reach" of the state down to the local and individual level is secured by the socially implemented forms of power that are locally expressed (bank inspectors, law enforcement agencies, tax auditors, ...).

This is an example of a large social structure that operates through a high degree of formal institutionalization. But some of the examples mentioned above depend primarily on informal mechanisms -- the workings of widespread beliefs and attitudes, along with a diffused willingness of individuals to "enforce" the requirements of the structure. Structures relying primarily on informal mechanisms include the Indian marriage system or the English class system.

Is "race" a structure in American society? Plainly it possesses some of the key elements identified above. The reality of race leads to an uneven distribution of opportunities and outcomes, so "race" is a social fact with distributive consequences. It has the element of coercion: racial prejudice and patterns of discrimination are imposed on individuals without an "opt-out" possibility. And we can identify many of the social mechanisms through which race and racial discrimination work; so the category possesses microfoundations. Today many of those mechanisms are "informal" rather than "formal"; but of course the legal institutionalization of racial discrimination is a recent fact in American history. So "race" is a structural feature of American society.

Several of the examples mentioned above appear to fall outside the category of social structure, however; for example, "Chinese peasantry". These examples appear to be large factors that play a role in large social structures, but are more akin to elements than systems. So the structure that defines "Chinese peasantry" is the system of property, agriculture, and kinship that defines the peasant's role and opportunities in society; the category of "peasant" identifies one node within that system or structure.

What about "the city of Chicago"? Is this a structure or some other category of social entity? I am inclined to say that the city of Chicago is a complex social entity, not a structure. It falls within a variety of structures in America and the world--the global trading system, the electoral process, and the politics of national funding for large cities; and it embodies within it a variety of smaller structures--the public school system, lending practices, nepotism. But the city itself does not function as a regulative system coordinating the activities of large numbers of individuals. Rather, it is a complex social entity composed of a mix of social practices, behaviors, systems, and relationships.

There are quite a few posts in the UnderstandingSociety blog on the topic of structures and agents; follow the structure label to find more.

How does rational choice theory relate to social facts and individual psychology?

Rational choice theory is a mid-level theory of human agency, intended to capture core features of human decision-making in order to provide a basis for abstract and generalized theories of the dynamics of various areas of social behavior. The disciplines of political science and economics make particularly extensive use of versions of rational choice theory (decision theory, expected utility theory, game theory, theories of parametric and strategic rationality) in designing theories and models of stylized circumstances of social action (e.g. market decision-making, production decisions, voting decisions, collective action decisions). Homo economicus -- the rationally self-interested preference- or utility-maximizing individual -- stands at the foundation of typical models in economics and political science.

The theory of economic rationality can be specified in numerous ways. In all its versions it is an abstraction from real human behavior, in two senses. The theory abstracts from idiosyncratic differences in reasoning across individuals; and it abstracts from other, perhaps systematic, factors that might influence reasoning (emotions and morals, for example). The theory allows for differences across individuals, of course, but primarily in the individual's preferences or utility function. (The nature of the decision rule is also a variable: more risk averse or less, optimizing or satisficing, maximin or maximize expected utility).

The question here is, what role does rational choice theory play in social explanations and in formal models in political science and economics, and how does it function in description of individual psychology and behavior?

Some formalistic economists and political scientists treat the assumptions of rational choice theory as purely formal axioms that can provide the basis for a mathematical treatment of a stylized problem -- solution to an n-person non-zero sum game, for example. These theorists are not concerned about the descriptive adequacy of the axioms, but rather the feasibility of employing the axioms to derive a solution to the problem.

This approach is unsatisfying, however, if we think that the results of formal economic or political analysis are supposed to be explanatory in some sense of actual social phenomena. Suppose we explain the low level of public contribution to public radio, by saying that the "contribution/non-contribution" game is an n-person prisoners' dilemma, and the mathematical solution to such a game demonstrates an equilibrium of low contribution. This mathematical finding is only potentially explanatory if we have some reason to think that the model bears a relevant relationship to the system of behavior it is modeling; the model assumes rationally self-interested maximizers; so the model is potentially explanatory of the public radio result only if the listeners are to some degree approximately well-described as "rationally self-interested maximizers." In other words, the rational-choice explanation of this real social situation appears to require that there be some degree of realism in the assumption of individual rationality. The purely formalistic interpretation of the axioms would render the account devoid of explanatory value.

This suggests a different approach to the question. It suggests that we should regard the assumption of rationality as an approximately true description of most human beings. Rational choice theory is an empirical theory of human behavior, at a high level of abstraction. "Abstract" in this context means "disregarding of interfering or contrary factors" -- as the theory of ideal gases is abstract in its disregard of intermolecular forces. In other words, the theory of rationality might be construed as a particularly abstract part of an empirical theory of human psychology.

If we take this approach, then we are naturally invited to test and improve upon this theory of human decision-making. Are there other factors of deliberation and action that need to be introduced? Are there differences across human groups and cultures with respect to the system of reasoning that individuals employ in practical decisions? Is the theory of maximizing rationality true of at least a certain range of individuals and decision-making problems? (Perhaps, for example, we are maximizing decision-makers when it comes to choosing a loaf of bread, but are influenced by emotions and commitments when it comes to choosing a political party to support.)

The advantage of a simple, abstract theory of deliberation (the theory of economic rationality) is that it provides a mathematically tractable way of modeling certain common situations of social action. If we advance a theory of deliberation and agency that postulates more nuance at the individual level and more variation across individuals and cultures, we may lose the ability to put forward models that result in equilibrium. More empirical adequacy may reduce the theoretical or deductive adequacy of the disciplines. However, it seems unavoidable that social science is better served by a theory of human agency and deliberation that is somewhat more faithful to actual human practical cognition. And it would remain possible that the narrow assumptions of economic rationality emerge as being adequately descriptive in certain well defined problem circumstances (the circumstances of anonymous markets, for example). Finally, it may be that other methods of aggregating from individual-level assumptions to models of collective behavior are feasible -- for example, the agent-based models that are advocated by the Santa Fe Institute.

There may be one additional reason why rational choice theory asserts a centrality that separates it from the rest of social psychology -- that is the role that rationality plays in a normative sense. We might think that reason and rationality are especially important human creations, and that it is valuable to have a theory of pure rationality (and its implications) even if the typical human reasoner falls far short of its assumptions.

Why are tastes and aversions beyond rational control?

Rational choice theory is a powerful foundation for thinking about social behavior (at least in its moderate versions). People have beliefs and goals; they survey the environment of choice and they arrive at actions that are intelligently related to the achievement of their goals.

However, as an exclusive, abstract description of human behavior, rational choice theory confronts a few major problems. A minor problem is the fact that people do not always act deliberatively. They may act out of impulse, habit, or example -- without devoting the thought processes to their current choices that would be necessary in order to formulate a rational plan in the circumstances. This is a minor problem, because this behavior itself may be rational in the "satisficing" sense: the stakes may be so low that it doesn't make sense to commit time and energy to the task of calculating what the best overall solution to the problem is. (Shall I take the triple cappuccino or the iced mocha today?)

More challenging is a much more substantial fact about human action and choice: there is a powerful set of psychological imperatives and constraints that make certain choices psychologically impossible even when they are "goal-maximizing". Take food and clothing choices as examples: the fact that fish heads are perfectly nutritious and cheap will never induce most Americans to order them on the menu. The fact that a pair of Bermuda shorts is a perfectly suitable attire in some settings will not induce someone to wear them to a black tie gala in place of the tuxedo. It is as if the decision-making system is loaded with constraints of taste, preference, aversion, and norm that make some decisions simply impossible.

This fact might be described as the workings of "culture"; it might be categorized under the heading of "norms and values"; or it might be assigned to the "workings of personality and affect." But whatever description we offer, it is plainly a factor that needs to be incorporated into a full theory of human agency and choice.

It is not particularly difficult to model a "decision-making system" that incorporates the workings of tastes, aversions, and norms as well as goal-directed rationality. The more challenging task lies at the level of psychological theories of individual development (how does the individual acquire and incorporate these cultural and normative constraints?) and sociological theories of transmission of these sorts of constraints. What are the institutional and cultural mechanisms through which a system of tastes, aversions, and norms are transmitted throughout a group or population?

And, finally, there is the task for behavioral science of incorporating the empirical findings that this set of observations permits concerning the ways in which real agents process experience and arrive at decisions, into aggregate models of collective behavior. How should the abstract models of rational choice theory be extended to include these factors of affect, taste, and aversion? Are these non-rational factors so idiosyncratic that they cannot be incorporated into behavioral science? Or are there regularities at the level of individuals that permit aggregate consequences at the level of group behavior? (And is it possible that we have arrived here at the theoretical nexus of "marketing science" -- the discipline aimed most directly at understanding and controlling the behavior of groups of consumers?)

(An interesting edited volume by Lupia, McCubbins and Popkin explores some of these issues: Elements of Reason: Cognition, Choice, and the Bounds of Rationality .)

Basis for the social science disciplines

Is there a reason or rationale underlying the scope and methods of the social science disciplines? Or is the current division of the subject matter arbitrary and contingent on accidents in the history of thought (as perhaps Michel Foucault believes in The Archeology of Knowledge and The Discourse on Language)?

There are abbreviated definitions of the subject matters of sociology, political science, of economics -- "Sociology is the study of groups and norms," "political science is the study of the institutions and behavior through which political decisions are made," "economics is the study of rational behavior in the context of scarcity". And likewise for the core methods of inquiry and explanation. But the questions remain: Is this a logical way of covering the domain of possible inquiry?Are there areas of phenomena that are overlooked in this taxonomy? And pragmatically--is this combination of topics, scopes, and methods likely to solve the problems of explanation and policy to which we would like the social sciences to contribute?

It is worth noticing in this discussion that each of the core disciplines of the social sciences is actually an umbrella encompassing a wide range of sub-disciplines, and these sub-disciplines themselves show significant variation in assumptions about subject matter, ontology, and methodology. Within political science, for example, there are wide rifts between new institutionalists, rational choice theorists, comparativists, area specialists, and American politics specialists, and there is no common perspective that gives substantial coherence across these divides. Similar observations are true of economics, anthropology, and sociology as well.

So how should we begin to analyze the status and adequacy of the current definitions of the social science disciplines?

What would we want from a division of the disciplines in a large field of study (biology, physics, social science, psychology)? This is an epistemic question: we want to know how best to go about acquiring knowledge about a broad domain of phenomena. We would want to be sure that the most fundamental processes and the most practically important phenomena are given close scrutiny. We would want to be sure that there are a variety of methods of inquiry that are well designed and effective in probing the nature of the phenomena under study. And, of course, we would want the disciplines to be organized in such a way that practitioners are motivated and evaluated towards valid discovery. Finally, it would appear logical that we would want there to be mechanisms of scientific communication through which discoveries and insights in one discipline may inform or deepen the discoveries of other neighboring disciplines.

This last point deserves emphasis. Disciplines provide focus; they encourage researchers to dig deeply into the specialized problems and methods that have been defined by the discipline. But it is also true that specialization creates tunnel vision -- with the result that scientific understanding of a complex phenomenon may miss essential parts of the process because they overlap disciplinary definitions of subject matter. So a logical expectation of the organization of scientific knowledge would presumably include a process through which interdisciplinary sharing is encouraged and facilitated.

It needs also to be noted that it is entirely possible for a discipline to be mis-conceived. The founders may have taken a wrong turn in highlighting what appeared to be the most important phenomena and mechanisms; the discipline may have adopted methodological commitments that were fashionable at a time but poorly fitted to the research problems of the subject matter (extreme behaviorism in psychology, for example); the disciplinary institutions (journals, universities) may have designed procedures of peer review that were discouraging to genuine progress in the discipline's ability to gain knowledge about the subject matter.

There are many threads that this subject opens. But a few preliminary observations are justified. First, it is worth observing that the social world does not come to us with a prior division of phenomena into "economic," "ethnographic," or "sociological." So the social world itself does not dictate the way in which we parcel out research problems across specialists. Almost all social phenomena have dimensions of each of these characteristics, and the methods of each of these disciplines are relevant to inquiry and explanation of a single phenomenon. So the insistence on using only the methods of one's discipline in analyzing a complex social phenomenon is a problem--along the lines of the saying that "to a person with a hammer, everything looks like a nail". Second, it is noteworthy that each of the major social science disciplines has undergone harsh "methodology wars" in the past several decades--between rational choice theory and more empirical research in political science, between quantitative and qualitative researchers in sociology, or between interpretive and materialist ethnography methods. Are these disputes productive of further discovery into the workings of the social world? It is not evident that they are. And third, the points made above about the general utility of interdisciplinary communication and collaboration seem especially applicable to the social sciences. Given the inherently complex and mixed nature of social phenomena, surely the social sciences would benefit from a greater degree of interdisciplinarity and mutual respect. Pluralism in theory and method would seem to best serve the goals of the social sciences.

(See Andrew Abbott, Chaos of Disciplines, for a lively and illuminating examination of the social science disciplines.)

Are social facts reducible to something?

What is the relationship between facts about society and facts about individuals?

Reducibility means that the statements of one scientific discipline should be logically deducible from the truths of some other "more fundamental" discipline. It is sometimes maintained that the truths of chemistry ought in principle be derivable from those of quantum mechanics. A field of knowledge that is not reducible to another field R is said to be "autonomous with respect to R". Philosophers sometimes further distinguish "law-to-law" reduction, "type-to-type" reduction, "law-to-singular-fact" reduction, and "type-to-token" reduction.

Are social sciences such as economics, sociology, or political science reducible in principle to some other more fundamental field--perhaps psychology, neurophysiology, or the theory of rationality?

To begin to answer this question we must first decide what items might be reduced: statements, truths, laws, facts, categories, or generalizations. Second, we need to distinguish several reasons for failure of reduction: failure in principle, because events, types, and laws at the social level are simply not fixed by states of affairs at "lower" levels, and failure for reasons of limits on computation. (The motions of a five-body system of stars might be determined by the laws of gravitation even though it is practically possible to perform the calculations necessary to determine future states of the system.)

So now we can consider the question of social reduction in a reasonably clear form. Consider first the "facts" that pertain to a domain of phenomena--whether these facts are known or not. (I choose not to concentrate on laws or generalizations, because I am doubtful about the availability of strong laws of social phenomena.) Do the facts of a hypothetically complete theory of human psychology "fix in principle" the facts of economics or sociology, given appropriate information about boundary conditions?

One important approach to this problem is the theory of supervenience (Jaegwon Kim, Physicalism, or Something Near Enough). A level of description is said to supervene upon another level just in case there can be no differences of state at the first level without there being a difference of state in the second level. The theory is first applied to mental states and states of neurophysiology: "no differences in mental states without some difference in neurophysiology states." Supervenience theory implies an answer to the question of whether one set of facts "fixes in principle" the second set of facts. (It has been taken as obviously true that social facts supervene upon facts about individuals; how could it be otherwise? What other constitutive or causal factors might influence social facts, beyond the actions and ideas of individuals?) If the facts about social life supervene upon facts about the psychological states of individuals, then it follows that the totality of facts about individual psychology fixes in principle the totality of facts about social life. (Otherwise there would be the situation that there are two total social worlds corresponding to one total "individual psychology" world; so there would be a difference at the social level without a difference at the level of individual psychology.)

So this provides the beginnings of an answer to our question: if we believe that social facts supervene upon facts about individuals, then we are forced to accept that the totality of facts about individuals "fix" the facts about society.

However, supervenience does not imply "reducibility in principle", let alone "reducibility in practice" between levels. In order to have reducibility, it is necessary to have a system of statements describing features of the lower level which are sufficient to permit deductive derivation (or perhaps probabilistic inference) of all of the true statements contained in the higher-level domain. If it is a social fact that "collective action tends to fail when groups are large", then there would need to be set of statements at the level of individual psychology that logically entail this statement. Two additional logical features would appear to be required for reduction: a satisfactory set of bridge statements (linking the social term to some construction of individual-level terms; "collective action" to some set of features of individual agents, so there is a mapping of concepts and ontologies between the two domains), and at least some statements at the lower level that have the form of general laws or law-like probabilistic statements. (If there are no general statements at the lower level, then deductive inference will be limited to truth-functional deduction.)

Now it is time for a speculative leap: a judgment call on the question of whether we ought to look for reductive links between social facts and individual-level facts. My intuition is that it is not scientifically useful to do so, for several reasons. First is the point about computational limits: even if the outcome of a riot is "fixed" by the full psychological states of participants ex ante and their strategic interactions during the event--it is obviously impossible to gather that knowledge and aggregate it into a full and detailed model of the event. So deriving a description of the outcome from a huge set of facts about the participants is unpromising. Second, it is telling that we need to refer to the strategic interactions of participants in order to model the social event; this means that the social event has a dynamic internal structure that is sensitive to sub-events that occur along the way. (Jones negotiates with Smith more effectively than Brown negotiates with Black. The successful and failed negotiations make a difference in the outcome but are unpredictable and contingent.) Third, the facts at the social level rarely aggregate to simple laws or regularities that might have been derived from lower-level laws and regularities; instead, social outcomes are contingent and varied.

So for a variety of reasons, it is reasonable to take the view that social facts supervene upon facts about individuals, but that social explanations are autonomous from laws of psychology. (This final point might be paraphrased as "the laws of psychology underdetermine social outcomes.")

How does transportation function as a mid-range social cause?

Transportation systems function to move people, goods, and ideas. Rail systems, road networks, airline systems, and water transport provide links between places that permit more reliable and low-cost movement of people and goods from point to point than previously available. The history of transportation is simultaneously a history of technology change, population movement, colonialism, economic growth, business development, and the spread of disease.

Transportation systems are particularly interesting when we consider their capacity for conveying social causation. Consider these examples of causal relations mediated by transportation systems:

• Extension of a rail network stimulates the growth of new towns, villages and cities in North America in the 1880s.
• Establishment of a direct air travel link between A and B causes the more rapid spread of disease between these locations.
• Breakdown of the administration of the rail system leads to logistics bottlenecks and military defeat of the French army in the Franco-Prussian War.
• Regular river travel throughout the Canton Delta in China leads to the rapid spread of revolutionary ideas during the Republican Revolution, as travelers and merchants move easily from place to place.
• Commodity price correlation increases between Chicago and New York as a result of regular and cheap rail transport between these two cities.
• New business institutions (grain futures markets and grain elevators) are created to take advantage of cheap regular rail transport (Nature's Metropolis: Chicago and the Great West).
  

Examples can be multiplied. But the central point is that transportation is a robust causal mechanism that mediates many important social processes and outcomes. And its causal effectiveness is fairly transparent: new transportation opportunities create new options for social actors, who take advantage of these opportunities in choosing a place to live and work, in pursuing political goals, in moving armies, and in generating income. So transportation is a causal mechanism whose microfoundations are especially visible, and whose causal consequences are often very large.

(See "Transportation as a Large Causal Factor" for more on this subject.)

Varieties of social causation

What are some chief mechanisms through which social behavior is shaped and social outcomes are caused? Ideally the best answer to this question would result from a survey or inventory of many explanations. But consider some high level possibilities that could serve as a causal mechanism bringing about a social phenomenon of interest.

Selection mechanisms. Why are passengers on commercial aircraft better educated than the general population? Because most airline passengers are business travelers, and high-level and mid-level business employees tend to have a higher level of education than the general population.

Evolutionary explanations. Why does the level of firm efficiency tend to rise over time? Because the net efficiency of a firm is the product of many small factors. These small factors sometimes change, with an effect on the efficiency of the firm. Low efficiency firms tend ultimately to lose market share and decline into bankruptcy. Surviving firms will have features that produce higher efficiency.

Imitation mechanisms. Why did the no-huddle offense become so common in the NFL in the 1980s? Because it was successful for a few teams, and others copied the offense in the hope that they too would win more games.

Rational-intentional explanations. Why do rebellions often fizzle out? Because participants are rational agents with private goals, and they make calculating decisions about participation.

Aggregative explanations (aggregate consequences of individual-level strategies). Why does technological innovation occur continuously within a market-based society? Because manufacturers are constantly looking for lower-cost and higher-value-added methods of manufacturing, and this search leads them to innovations in products and technologies.

Conspiracy explanations (covert strategems of the powerful). Why did the United States move away from passenger railroads as the primary form of intercity transportation? Because powerful interests took political actions to assure that private automobiles would be encouraged as the primary form of transport.

Mentality explanations (behavior is changed by changing beliefs and attitudes). Why were so many Quaker men conscientious objectors at great personal cost during World War II? Because their religious beliefs categorically rejected the violence in war and they refused to participate in this immoral activity.

Historical / path-dependency explanations. Why do we still use the very inefficient QWERTY keyboard arrangement that was devised in 1874? Because this arrangement, designed to keep typists from typing faster than the mechanical keyboard would permit, was so deeply embodied in the typing skills of a large population and the existing typewriter inventory by 1940 that no other keyboard arrangement could be introduced without incurring massive marketing and training costs.

A simple sociology

What is involved in providing a scientific study of society--a scientific sociology?

Several features of science are crucial. Scientific claims are intended to be true and rationally supportable. Scientific knowledge is based on empirical research and rigorous reasoning. Science provides a basis for explaining the phenomena it considers. And science depends upon the idea of critical research communities: peers and collaborators who challenge, test, evaluate, and extend a set of results. In addition to these core features, positivist philosophers have added a few features drawn from the experience of the natural sciences. These observers hold that science involves the discovery of strong generalizations and laws that describe and govern empirical phenomena; that explanation means subsumption under some of these laws; and that natural phenomena constitute a law-governed, interconnected system.

Positivism is a poor theory of the social sciences, because the phenomena of social life do not conform to the law-governed ontology stipulated for natural phenomena. But let us stick with the minimal set of features and consider what kind of science is possible for social life.

First, sociology involves description. Social phenomena are observable, and it is straightforward to design rigorous research efforts aimed at establishing the facts about a particular domain. This aspect of sociology involves rigorous empirical study of social phenomena. Examples of descriptive research include ethnographic research and micro-sociology along the lines of the Chicago School. But large-scale description is feasible as well, including empirical description of large social patterns and institutions.

Descriptive findings often take the form of statistical estimates of the frequency of a feature within a group--for example, rates of suicide among Protestants (Durkheim). Properties may be correlated with one another within a given population; variation in one variable may be associated with variation in another variable. Descriptive research can thus sometimes reveal patterns of behavior or social outcomes--for example, patterns of habitation and health status. And patterns such as these invite efforts to find causal relationships among the characteristics enumerated.

Second, sociology involves discovery of social causation and mechanisms. Is there such a thing as social causation? What does social causation derive from? What is the ontology of "social necessity" (analogous to natural necessity)--the way in which one set of circumstances "brings about" another set of outcomes? In general we can begin with an ontology grounded in purposive social action by agents within institutional settings and environments. Social causation derives from the patterns of behavior that are produced in this setting. (For example, we can explain the degradation of environmental quality of a common resource as the consequence of free-riding behavior.)

Third, sociology can provide explanations of some social outcomes as a causal consequence of proposed social mechanisms. Once we have a generic idea of what social causal mechanisms look like, we can turn to specifics and try to discover the processes through which behavior
is created and constrained. So we can try to discover or hypothesize the mechanisms through which tropical agriculture tends to under-serve farmers (Bates). Social theories are hypotheses about social causal mechanisms; so theories provide a basis for explanation of social phenomena.

Research and explanation along these lines creates major and visible limitations on the degree of systematicity, interconnection, and determination that sould be expected of social phenomena. The social world is highly contingent, the product of many independent actors. So we should only expect a weak degree of systematic variation among social phenomena.

Finally, the epistemic setting provided by the disciplinary institutions offers a basis for estimating the rational credibility of social science knowledge: journals, peer review, tenure evaluation. Social research and explanation remains fairly close to the level of the facts. Researchers in the disciplines and sub-disciplines are charged to test and explore the empirical and theoretical claims of their peers.

The results of a science including these components will be empirically disciplined, theoretically eclectic, and systemically modest. The goal of providing an over-arching theory that demonstrates the systematic integration of the social is abandoned.

(It is worth noting that there is a period in the history of sociology when the epistemic values of the discipline were most consistent with this view. That was the period of the Chicago School. See Andrew Abbott's Department and Discipline: Chicago Sociology at One Hundred).

Are there historical structures?

The French Revolution began in 1789. It was caused by conflict between the aristocracy and the monarchy. Eventually it developed into violent conflict in every region of France. It created more lasting change in French society than did the Russian Revolution.

These statements purport to refer to an extended but unified historical thing, the French Revolution. This thing is assigned a place within a causal system, being caused by one set of factors and having causal consequences for other factors. It is considered a suitable topic for comparison with other such things (the Russian Revolution).

But what does the historical reality of the French Revolution consist in? Notice, to begin, that the revolution comprises a huge constellation of events and actions, both small and large. Were any of these events "the definitive moment" in the revolution--the decisive event that constituted the constellation as a revolution rather than a "period of unrest"? Is it possible to distinguish clearly between core events and peripheral, minor events--not to speak of events that are wholly unrelated to the revolution? Most radically, would it be possible to construct the events of 1789 in such a way that no revolution occurred at all?

One possible answer to these questions is to reply that the events directly associated with the overthrow of the monarchy and the establishment of a different form of political power constituted the essence of the revolution. But what if later historians were to conclude that the transfer of power was illusory, and that the same interests in society continued to govern? In fact, if the monarchy had been restored in 1830 we might reasonably say that "no revolution occurred, only an interruption of monarchy." Would either of these possibilities represent a refiguring of the historical picture in which the seizure of power is minor and background rather than major and foreground? And would this not be a basis for doubting that "a revolution occrred in 1789"?

It seems best to understand "the French Revolution" as an intellectual construction--one possible way of knitting together the congeries of events that occurred during this time in France. Some constructions of these facts are more plausible than others, so it is possible to have rational dispute about the alternative construals of the constellation of events. But there is no essential fact of the matter that a revolution occurred in France in 1789. This doesn't derogate the status or facticity of the constituent events. But it does assert that the historian's act of composing events and actions into a large historical structure is an act of construction rather than recognition.

The heterogeneous social: institutions

Populations and groups are inherently diverse; virtually any property that might be attached to an individual shows variance across the group. So we have to pay special attention to specifying what we mean when we ask for a "measurement" of a property of a group. This is the basic ontological fact that undergirds a critical approach to quantitative social and behavioral science. And it means that we need always to be considering the variance within the group with respect to the property, the shape of the distribution, as well as the mean value of the property.

It turns out that social phenomena are heterogeneous at the level of institutions, mentalities, practices, and causes as well. Later posts will consider other forms of social heterogeneity. The topic here is institutional heterogeneity. An institution is a system of rules through which a set of social behaviors are mediated. Rules may be enforced through clear third-party enforcement powers (formal institutions) or diffuse participant enforcement practices (informal institutions). Examples of institutions include contract law (formal), cooperative labor-sharing (informal), marriage systems (formal and informal), and tenure systems (formal). Institutions are embodied in the beliefs, values, attitudes, and motivations of socially constructed individuals at various levels of action; they act to constrain and incentivize individual behavior in ways that are to some extent independent of the actions and preferences of those individuals. (That is, the individual is rarely in a position to directly change the rules of the institution so as to serve his/her goals better.) So institutions are both caused by (embodied in) the social consciousness of an extended set of social actors, and are causal in shaping the future behavior of an extended set of social actors.

Institutions have origins -- they come into being at a time and place. So we can ask the question, "what explains the fact of the emergence of the institution and the particular characteristics it possesses at that point?" And institutions undergo processes of development over time -- they undergo change in some characteristics, incorporate new scope and function, and gain new coalitions of supporters and opponents. So we can ask the question, "what factors explain the processes of change that the institution undergoes?" (Kathleen Thelen's How Institutions Evolve: The Political Economy of Skills in Germany, Britain, the United States, and Japan provides a very good account of the ways in which we need to investigate the origins and development of various important social institutions.)

Institutions are sometimes grouped together into broad categories or classes in terms of social function (what does the institution do?), observable characteristics (what does the institution look like?), and social functioning (how does the institution work?). So, for example, we might want to study institutions of marriage-partner selection, irrigation management, or institutions that regulate common property resources such as forests or wetlands; Governing the Commons: The Evolution of Institutions for Collective Action. In each case the group of institutions is defined in terms of the common social problem that they solve.

Now we can frame the task of one important area of sociology and political science research: to undertake careful comparative research concerning the instances of institutions included within a category. In what ways are different examples similar and different from each other? How have parallel or divergent institutional complexes emerged to solve broadly similar social problems? What causal processes can be observed in the workings of these several examples? How do these institutional matrices influence and constrain the forms of behavior that flow through them? (So, in the book by Kathleen Thelen mentioned above, the author considers the national-level institutions of skilled-labor training that have evolved in Germany, UK, USA, and Japan; she considers the effects that these different regimes have on the flow of skilled workers; and she analyzes the political coalitions that were relevant in establishing a particular configuration of the institution.)

Here, finally, we can address the issue of institutional heterogeneity. Given the ways that institutions are formed, changed, and embodied, we should expect that there will be two forms of diversity among institutions. First, it is clear that there are normally multiple ways of solving a particular social problem (training workers for industry, managing prisoners, administering social welfare subsidies). So we should expect that there will be a range of institutional matrices that have emerged across societies to handle these challenges, and we can learn quite a bit about social causation by examining these differences and how they work. And second, given that institutions are "malleable" and dynamic, we should expect that institutions will show diversity within their own life courses. As powerful agents and coalitions shift in their powers and needs, as other constituents acquire more or less influence in setting the agenda for the institution, we should expect an ongoing process of modification of the institution over time.

The heterogeneous social: groups

A social whole -- the city of Chicago, for example -- is a densely various empirical reality. At virtually every level of scale there is variance with respect to social characteristics -- income, health status, ethnic or social identity, political adherence and preference, age, race, or occupation. Neighborhoods differ from each other -- but equally, we find variance within neighborhoods as well.

Given this fact of radical non-homogeneity of social characteristics, what is involved in arriving at knowledge about such a reality?

It is evident that we are forced to arrive at generalized descriptions, at some level of scale or granularity. It is neither feasible nor explanatory to provide a "fully" detailed description of a population, individual by individual. Instead, our challenge is to arrive at some ways of segmenting the population into groups that will prove felicitous in revealing causal connections among attributes or circumstances. Groups may be defined with unlimited range: geographically, occupationally, racially or ethnically, educationally, politically, ... We can then observe and measure the distribution and means of various characteristics across these groups (attitudes towards the Patriot Act, for example) and we can consider whether there are meaningful differences across groups with respect to these characteristics. Finally, we can try to find causal explanations of these differences. Are Arab-Americans more distrustful of national security laws than Asian-Americans? Are poor people more prone to asthma than affluent people? Are doctors more favorable to higher taxes than skilled-trades workers? What factors might causally explain these differences?

The point here is that social knowledge requires recognition of the inherent heterogeneity of social phenomena and a fertile effort to find ways of segmenting this heterogeneous reality that shed light on social causation and patterns of behavior. And, importantly, it is important to recognize that any level of granularity of analysis could be further partitioned and more fully described--sometimes with important insight.

There is no "fundamental" or "optimal" level of analysis and description that captures the whole of Chicago. Instead, anthropology; sociology, and political science can continually pursue the upward and downward research journey of discovering meaningful group-level patterns or regularities, and pressing into a deeper understanding of the diversity of the phenomena under study.

Social knowledge: measurement of properties in diverse groups

When we gain knowledge about silver, DNA, or cholera, we can study virtually any samples of the item and arrive at a description of its properties and causal powers, and this description will correspond accurately to other instances as well. We learn about the type by learning about the individuals, and we don't have to worry about substantial differences among individuals in the type. Cholera is cholera, whether it occurs in Mexico City or Bangalore. So knowledge we acquire about a few instances can be generalized to other instances. This feature of "type-uniformity" is found in many of the types of entities studied in the natural sciences.

There are exceptions in the natural sciences; there are classes of phenomena that embody substantial variance among individuals in the class. Hurricanes and volcanoes are examples of "type-heterogeneous" concepts in the natural sciences. In these examples, the phenomena are grouped together in terms of a set of crude observable characteristics; it is then a question for research to determine whether there are common structures and causal backgrounds that constitute one or more sub-groups of items within the classification. But more typical types of entities in the natural sciences fall into "natural kinds" with common structural and causal properties.

Consider now what is involved in arriving at knowledge about a complex social reality -- the city of Chicago, for example. The social reality of Chicago is constituted by the social behaviors of the individuals who live in Chicago and the institutions that these individuals populate. Consider some of the topics concerning which we might want to gather knowledge:

• What is the health status of Chicagoans?
• What is the climate for race relations in Chicago?
• What is the standard of living in Chicago?
• What is the rate of economic growth in Chicago?
• How do people in Chicago feel about higher education?
• What is the climate for new-business startup in Chicago?
• How well do the institutions of the mayor's office and the city council work?
• How are the Chicago public schools performing?

Notice that almost all these questions invite us to consider the heterogeneity of the population and its organizations. There is an average level of heart disease in the city. But the average is a poor indicator of any particular person's health, because there are socially significant differences across groups with respect to almost all these questions. So a study of health in Chicago requires that we consider some of the ways in which different groups are affected by a variety of circumstances in ways that systematically affect their health status.

These facts suggest that a statement about a social characteristic of a large population needs to be nuanced, indicating the degree of variation of the characteristic across individuals and groups within the population as well as the most significant sub-populations showing the greatest variance from the group mean behavior. Race, ethnicity, gender, geography, age, income, employment, labor-union membership, and education might be variables that define groups with significantly different measures of the variable of interest. And once we have determined that certain social characteristics (race, income, and union membership, let us say) are associated with the outcome of interest (health status, say), then we are stimulated to ask the causal question: what are the social mechanisms at work that produce the associations that are discovered?

Is industrial agriculture sustainable?

The world's food system depends largely on a farming system with post-green-revolution techniques: new seed varieties, substantial use of chemical fertilizers and pesticides, large-scale irrigation, machine-based cultivation, production for large markets, and separation of production from consumption by long distances. This system shows the highest productivity the world has ever seen, whether measured in terms of labor, land, or cost. And the system does a fairly good job of producing enough food for the world's 6 billion people.

But is this system sustainable?

Several large issues arise. First, the system is energy-intensive, so it poses significant demands on the petroleum economy. The use of petroleum and energy pervades the process: fuel for cultivation and transport, energy and inputs into the production of chemical fertilizers and pesticides, energy consumed in irrigation. So a part of the sustainability question has to do with the energy challenge the globe faces.

Second, industrial agriculture has massive environmental effects. Fertilizer and animal waste runoffs lead to groundwater and river pollution (extending into the Gulf of Mexico). Degradation and loss of topsoil is another large and longterm environmental effect with serious consequences for future agricultural productivity. And methane produced by large-scale cattle- and swine-rearing represents a measurable component of global warming. So the environmental effects of industrial agriculture are very large--once again raising the question of global sustainability.

Finally, industrial agriculture, and the integrated global commodity markets from which this system is inseparable, have large and destructive consequences for traditional agriculture and the communities built around traditional farming. The effect of NAFTA and the export of US corn to Mexico has been massive in its disruption of maize-based culture and communities in Mexico.

Three questions are central. First, is this system sustainable in the narrow sense, or will it collapse of its own burden of soil, water, and air pollution in the next 50 years? Second, is it a potential part of a larger sustainable global system of production and consumption from an environmental point of view? Or does global sustainability require radical change in agriculture? And finally, are there feasible alternative systems that would be less environmentally harmful, more sustainable, and less disruptive of agrarian communities? Are these alternatives scaleable to the needs of mass societies, large cities, and a global population of 6-8 billion? Can alternative systems achieve the productivity needed to feed the world's population?

Environmentalists, global justice activists, and food activists have argued that there are alternatives. The Fair Trade movement is trying to get first-world consumers to favor fair-trade-certified products in their consumption--giving greater security and income to third-world farmers. Organic farming advocates argue that a system of smaller farms, organic fertilizers, innovative pest control, and farming techniques more suited to the local environment would have a smaller environmental footprint. "Local food" activists support the idea of shifting consumption towards products that can be grown locally--thus reducing transport and refrigeration and giving more of a market for small farmers.

So there are alternatives in technique and policy that could result in different farm characteristics that are more favorable from the points of view of justice, sustainability, and community. The hard question is whether these alternatives could be scaled to the volume needed to feed a mass population. And this is a question that demands careful scientific analysis.

(An excellent current critique of industrial agriculture is Michael Pollan's The Omnivore's Dilemma: A Natural History of Four Meals.)

Historians and the philosophy of history

How should the philosophy of history interact with the practice of working historians?
The philosophy of history is challenged to discover and explore the most fundamental questions about historical inquiry and knowledge. How should this research be conducted? And how should the philosopher's development of the subject make use of the practice of the historian? Look at this question from the point of view of the historian, and we will find that the separation between "doing" and "reflecting upon" history is not as sharp as it might appear.

For the best historians, there is no recipe for good historical inquiry and exposition. There are methods and practices of archival research, to be sure, and there are general recommendations like "be well informed about existing knowledge about your subject matter." But the great historians take on their subjects with fresh eyes and new questions. They often arrive at novel ways of framing their historical questions; they find new ways of using available historical evidence, or finding new historical evidence; they discover new ways of drawing inferences from historical data; they arrive at new ways of presenting their knowledge and narratives; and they question existing assumptions about "causation," "agency," or "historical period." As the historian grapples with the topic of research and the evidence that pertains to the topic, he or she is forced to think creatively about issues that go to the heart of historical inquiry and reasoning. In other words, the historian is forced to think as a philosopher of history, in order to achieve new insights into the problems she considers.

There is a less creative approach to historical research, of course. One can choose a familiar topic; seek out some new sources that have not yet been fully explored; adopt some familiar theoretical motifs; and place the findings into a standard narrative for publication. This mechanical approach resembles "normal science" for historians. But the results of this type of approach are inherently disappointing; it is unlikely in the extreme that new historical insights will emerge.

So when we consider the work of really imaginative historians, we find that the researcher is functioning as a philosopher of history at the same time as he or she is developing an innovative approach to the historical question under examination. And this means that the philosopher can gain great insight by working very carefully with the writings of these great historians. The philosopher can probe questions of historical inquiry, historical reasoning, historical presentation, and historical knowledge, by thinking through these questions in conversation with the working historian.

Consider a few examples that illustrate this productive possibility. First, consider the evolving state of affairs in historical treatments of the French Revolution. In the past forty years historians have taken a shifting series of perspectives on the events, social conflicts, cultural circumstances, and political realities of the Revolution. New research and new narratives have emerged on the Ancien Regime, the revolution, the Terror, and the consolidation of power by Napoleon. Fertile historians such as Soboul, Cobb, Darnton, Schama, Sewell, or Chartier have tested and explored a variety of new perspectives -- from Marxism, from social history, from cultural studies. And they have provided a much more nuanced body of knowledge about the social and cultural reality of the Revolution. This body of work provides a rich domain of conceptual and historiographical material for the philosopher of history.

A second example is the lively debate that has occurred about comparative economic history of England and China. In the past 15 years historians of Chinese economic history have challenged standard models of economic development and have argued for a more balanced comparative economic history for Eurasia. This debate has moved into great detail in the effort to answer such basic questions as whether China's agricultural economy was declining, static, or rising in productivity in the 17th century; or whether the standard of living was higher or lower at opposite ends of Eurasia. Once again, a philosopher of history can find great stimulation to further conceptual and philosophical research by studying this debate in detail; the debate provides a living example of how historical knowledge is born.

So my answer to the primary question here is this: that the philosophy of history needs to be fully immersed in some specific historical debates involving the most creative and imaginative historians. Careful study of these debates and sustained interaction with historians like these will lead in turn to much more developed understanding of the nature of historical reasoning.