Bodily cognition

Traditional cognitive science has been largely organized around the idea of the brain as a computing device and cognitive systems as functionally organized systems of data-processing. There is an emerging alternative to this paradigm that is described as “4E Cognition,” where the four “E’s” refer to cognition that is embodied, embedded, enactive, and extended. For example, there is the idea that perception of a fly ball is constituted by bodily awareness of arms and legs as well as neurophysiological information processing of visual information; that a paper scratch-pad used to assist a calculation is part of the cognitive process of calculation; or that a person’s reliance on her smartphone for remembering names incorporates the smartphone into the extended process of recognizing an acquaintance on the street.

The 4E-cognition approach is well represented in The Oxford Handbook of 4E Cognition, edited by Albert Newen, Leon de Brun, and Shaun Gallagher, which provides an exposure to a great deal of very interesting current research. The fundamental idea is the questioning of the “brain-centered” approach to cognition that has characterized much of the history of cognitive science and neuroscience — what participants refer to as “representational and computational model of cognition”; RCC. But the 4E approach rejects this paradigm for cognition. 

According to proponents of 4E cognition, however, the cognitive phenomena that are studied by modern cognitive science, such as spatial navigation, action, perception, and understanding others emotions, are in some sense all dependent on the morphological, biological, and physiological details of an agent’s body, an appropriately structured natural, technological, or social environment, and the agent’s active and embodied interaction with this environment. (kl 257)

Here is a summary statement of the chief philosophical problems raised by the theory of “4E cognition”, according to the introduction to the volume provided by Newen, de Brun, and Gallagher:

Thus, by maintaining that cognition involves extracranial bodily processes, 4E approaches depart markedly from the RCC view that the brain is the sole basis of cognitive processes. But what precisely does it mean to say that cognition involves extracranial processes? First of all, the involvement of extracranial processes can be understood in a strong and a weak way. According to the strong reading, cognitive processes are partially constituted by extracranial processes, i.e., they are essentially based on them. By contrast, according to the weak reading, they are non-constitutionally related, i.e., only causally dependent upon extracranial processes. Furthermore, cognitive processes can count as extracranial in two ways. Extracranial processes can be bodily (involving a brain–body unit) or they can be extrabodily (involving a brain–body–environment unit).


Following this line of reasoning, we can distinguish between four different claims about embodied cognition:


a. A cognitive process is strongly embodied by bodily processes if it is partially constituted by (essentially based on) processes in the body that are not in the brain;


b. A cognitive process is strongly embodied by extrabodily processes if it is partially constituted by extrabodily processes;


c. A cognitive process is weakly embodied by bodily processes if it is not partially constituted by but only partially dependent upon extracranial processes (bodily processes outside of the brain);


d. A cognitive process is weakly embodied by extrabodily processes if it is not partially constituted by but only partially dependent upon extrabodily processes. 

The last version of the claim (d) is identical with the property of being embedded, i.e., being causally dependent on extrabodily processes in the environment of the bodily system. Furthermore, being extended is a property of a cognitive process if it is at least partially constituted by extrabodily processes (b), i.e., if it extends into essentially involved extrabodily components or tools (Stephan et al. 2014; Walter 2014). (kl 259)

These are metaphysical problems on the whole: what is the status of cognition as a thing in the world, and where does it reside — in the brain, in the body, or in a complex embedded relationship with the environment? The distinction between “constituted by” and “causally affected by” is a metaphysically important one — though it isn’t entirely clear that it has empirical consequences.

Julian Kiverstein’s contribution to the volume, “Extended cognition,” appears to agree with this point about the metaphysical nature of the topic of “embedded cognition”. He distinguishes between the “embedded theory” (EMT) and “extended theories” (EXT), and proposes that the disagreement between the two families of theories hangs on “what it is for a state or process to count as cognitive” (kl 549). This is on its face a conceptual or metaphysical question, not an empirical question.

I show how there is substantial agreement in both camps about how cognitive science is to proceed. Both sides agree that the best explanation of human problem-solving will often make reference to bodily actions carried out on externally located information-bearing structures. The debates is not about how to do cognitive science. It is instead, to repeat, a debate about the mark of the cognitive: the properties that make a state or process count as being of a particular cognitive kind. (kl 590)

Embedded and extended theorists therefore agree that internal cognitive processes will often not be sufficient for explaining cognitive behaviors. (kl 654)

It might be thought to be analogous to the question, “what is the global trading network?” (GTN), and the subsequent question of whether systems of knowledge production are part of the global trading network (constitutive) or merely causally relevant to the GTN (extended causal relevance). But it is difficult to see how one could argue that there is a fact of the matter about the “reality of the global trading system” or the “mark of the cognitive”. These look like typical issues of conceptual demarcation, guided by pragmatic scientific concerns rather than empirical facts about the world.

Kiverstein addresses this issue throughout his chapter, but he arrives at what is for me an unsatisfactory reliance on a fundamental distinction between conceptual frameworks and metaphysical reality:

I agree with Sprevak, however, that the debate between EXT and EMT isn’t about the best conceptual framework for interpreting findings in cognitive science. It is a debate in metaphysics about “what makes a state or process count as mental or non-mental” (Sprevak 2010, p. 261) (kl 654)

The central claim of this chapter has been that to resolve the debate about extended cognition we will need to come up with a mark of the cognitive. We will need to say what makes a state or process count as a state or process of a particular cognitive kind. (kl 951)

But debates in metaphysics are ultimately debates about conceptual frameworks; so the distinction is not a convincing one. And, contrary to the thrust of the second quote, it is implausible to hold that there might be a definitive answer to the question of “what makes a state count as a state of a particular cognitive kind.” (Here is an earlier post on conceptual schemes and ontology; link.)

What this suggests to me is not that 4E theory is misguided in its notion that cognition is embedded, embodied, extended, and enactive; rather, my suggestion here is that the metaphysical questions about “constitution of cognition” and “the real nature of cognition” might be put aside and the empirical and systematic ways in which human cognitive processes are interwoven with extra-bodily artifacts and processes be investigated in detail.

Also interesting in the volume is Tadeusz Wiesław Zawidzki’s treatment of “mindshaping”. This topic has to do with another aspect of extended cognition, in this case the ability humans have to perceive the emotional and intentional states of other humans. Zawidski takes on the more traditional idea of “mindreading” (not the spooky kind, just the idea that human beings are hard-wired to perceive behavioral expressions of various mental states when performed by other people). He argues instead that our ability to read other people’s emotions and intentions is the result of a socially/culturally constructed set of tools that we learn. And, significantly, he argues that the ability to influence the minds of others is the crucial social-cognitive ability that underlies much that is distinctive in human history.

The mindshaping hypothesis rejects this assumption [of hardwired interpersonal cognition], and proposes an alternative. According to this alternative, our social accomplishments are not due to an individual, neurally implemented capacity to correctly represent each other’s mental states. Rather, they rely on less intellectualized and more embodied capacities to shape each other’s minds, e.g., imitation, pedagogy, and norm enforcement. We are much better mindshapers, and we spend much more of our time and energy engaged in mindshaping than any other species. Our skill at mindshaping enables us to insure that we come to have the complementary mental states required for successful, complex coordination, without requiring us to solve the intractable problem of correctly inferring the independently constituted mental states of our fellows. (chapter 39)

Here is how Zawidzki relates the mindshaping hypothesis to the 4E paradigm:

The mindshaping hypothesis is a natural ally of “4E” approaches to human social- cognition. Rather than conceptualize distinctively human social cognition as the accomplishment of computational processes implemented in the brains of individuals, involving the correct representation of mental states, the mindshaping hypothesis conceptualizes it as emerging from embodied and embedded practices of tracking and molding behavioral dispositions in situated, socio-historically and culturally specific human populations. Our socio-cognitive success depends essentially on social and hence extended facts, e.g., social models we shape each other to emulate, both concrete ones, e.g., high status individuals, and “virtual” ones, e.g., mythical ideals encoded in external symbol systems. And social cognition, according to the mindshaping hypothesis, is in a very literal sense enactive: we succeed in our socio-cognitive endeavors by cooperatively enacting roles in social structures. (chapter 39)

 This is an interesting approach to the important phenomenon of interpersonal perception. And it has immediate empirical implications: are there cross-cultural differences in “mindshaping” practices? Are there differences within a given culture according to socially relevant characteristics (gender, race, class)? Is it possible to track historical changes in the skills associated with human “mindshaping” practices? Were Victorian aristocrats different in their mindshaping capacities from their counterparts a century earlier or later?

There are many instructive implications of research within the umbrella of 4E cognitive science. But perhaps the most important is the license it gives researchers to think more broadly about knowledge, perception, intention, belief, and emotion than the narrowly neurophysiological versions of cognitive science would permit. This perspective allows researchers to pay attention to the interdependencies that exist between consciousness, thought, bodily action, joint activity, social context, and artifact that are difficult to incorporate into older cognitive theories. The model of the mind as the expression of a brain-computer-information machine is perhaps one whose time has passed. (Sorry, Alan Turing!)

Mechanisms thinking in international relations theory

source: Alex Cooley, “America and Empire” (link)

One of the most fundamental ideas underlying the philosophy of social science expressed here and elsewhere is the view that social explanations should seek out the causal mechanisms that underly the social phenomena of interest. So now we need to be able to say a lot more about what social mechanisms are, and how they relate to each other. Quite a bit of my own thinking has been devoted to this subject, and in a recent post I proposed that it would be useful to begin to compile an inventory of social mechanisms currently in use in the social sciences (link). There I suggested that it would be useful to find a motivated way of classifying the mechanisms that we discover.

Interest in mechanisms is taking hold in some sub-disciplines of political science. An especially clear statement of the appeal of the mechanisms theory of explanation for political science is offered by Andrew Bennett in “The Mother of All Isms: Causal Mechanisms and Structured Pluralism in International Relations Theory” (link). (Bennett is also co-author with Alexander George of the excellent book on case-study methodology, Case Studies and Theory Development in the Social Sciences.) In the current article Bennett reviews the progression that has occurred in IR theory from positivism and the covering law model, to the idea of high-level “paradigms” of explanation, to the idea of a diverse set of causal mechanisms as the foundation of explanation in the field. He calls the latter position “analytic eclecticism”, and he argues that it is a powerful and flexible way of thinking about the processes and research questions that make up the subject matter of IR theory.

In order to advance the value of mechanisms theory for working political scientists, Bennett argues that it will be helpful to attempt to classify the large number of mechanisms currently in use in IR theory in terms of a small number of dimensions. He proposes two dimensions in terms of which to analyze social mechanisms, which can be summarized as content and structure. The content dimension asks the question, what substantive social entities or properties are invoked by the mechanism? And the structure dimension asks the question, what is the nature of the relationship invoked by the mechanism? He proposes three large types of content: material power, functional efficiency, and legitimacy. And he suggests that there are four basic structures that can be formed: agent to agent, structure to agent, agent to structure, and structure to structure. (Notice that this corresponds exactly to the four arrows in Coleman’s boat, including the Type 4 “structure to structure” connection.) Here is how Bennett motivates this classification scheme:

This tripartite division of categories of mechanisms usefully mirrors the three leading ‘isms’ in the IR subfield: (neo)realism (with a focus on material power); (neo)liberalism (institutional efficiency); and constructivism (legitimacy). It thereby provides a bridge to the vast literature couched in terms of the isms, preserving this literature’s genuine contributions toward better theories on mechanisms of power, institutions, and social roles. (472)

Here is the resulting classification of social mechanisms that Bennett offers:

Others have found this approach to be promising. Here is an elaboration on Bennett’s classification by Mikko Huotari at the Mercator Institute for China Studies in Berlin:

(Thanks for sharing this classification, Mikko.)

I agree with Andrew in thinking that it is useful to find a non-arbitrary way of classifying mechanisms. It is quite worthwhile to make a start at this project. I’m not yet fully persuaded, however, by either of the axes that he proposes.

First, the content axis seems arbitrary — legitimacy, material power, functional efficiency. Why choose these substantive characteristics rather than a dozen other possible content features? Is it simply that these correspond to the three primary “isms” of IR theory — neorealism, neoliberalism, and constructivism (as he suggests earlier; 472)? But the thrust of the first part of the paper is that the “isms” are an unsatisfactory basis for guiding explanation in international relations theory; so why should we imagine that they serve to identify the crucial distinctions in content among social mechanisms? Would the content categories look different if we were taking our examples from feminist sociology, the sociology of organizations, or theories of legislatures? Bennett doesn’t assert that these content categories are exhaustive; but if they are not, then somehow the tabulation needs to indicate that there is an extensible list on the left. And are these categories exclusive? Can a given mechanism fall both into the legitimacy group and the functional efficiency group? It would appear that this is possible; but in that case classification is difficult to carry out.

Second, the structure axis. Why is it crucial to differentiate mechanisms according to their place within an agent-structure grid? Why is this an illuminating or fundamental feature of the mechanisms that are enumerated? Would this dimension explode if we thought of social organization as a continuum from macro to meso to micro (along the lines of Jepperson and Meyer (link), as well as several earlier posts here (link))?

An early question that needs answer here is this: What do we want from a scheme of classification of social mechanisms? Should we be looking for a strict classification with exhaustive and mutually exclusive groupings? Or should we be looking for something looser — perhaps more like a cluster diagram in which some mechanisms are closer to each other than they are to others?


We do have several other examples to think about when it comes to classifying mechanisms. In an earlier post I discussed Craver and Darden’s account of mechanisms in biology, and highlighted the table of mechanisms that they provide (link). It is evident that the Craver-Darden table is much less ambitious when it comes to classification. They have loosely grouped mechanisms into higher-level types — adaptation, repair, synthesis, for example; but they have not tried to further classify mechanisms in terms of the levels of the entities that are linked by the mechanism. So they offer one dimension of classification rather than two, and they leave it entirely open that there may be additional types to be added in the future. This is a fairly unexacting understanding of what is needed for a tabulation of mechanisms.

In Dynamics of Contention McAdam, Tarrow and Tilly offer a sort of classification of their own for the kinds of mechanisms they identify. They propose three types of mechanisms — environmental, cognitive, and relational (kl 375):

  • Environmental mechanisms mean externally generated influences on conditions affecting social life. Such mechanisms can operate directly: For example, resource depletion or enhancement affects people’s capacity to engage in contentious politics (McCarthy and Zald, ed. 1987).
  • Cognitive mechanisms operate through alterations of individual and collective perception; words like recognize, understand, reinterpret, and classify characterize such mechanisms. Our vignettes from Paris and Greenwood show people shifting in awareness of what could happen through collective action; when we look more closely, we will observe multiple cognitive mechanisms at work, individual by individual. For example, commitment is a widely recurrent individual mechanism in which persons who individually would prefer not to take the risks of collective action find themselves unable to withdraw without hurting others whose solidarity they value – sometimes at the cost of suffering serious loss.
  • Relational mechanisms alter connections among people, groups, and interpersonal networks. Brokerage, a mechanism that recurs throughout Parts II and III of the book, we define as the linking of two or more previously unconnected social sites by a unit that mediates their relations with one another and/or with yet other sites. Most analysts see brokerage as a mechanism relating groups and individuals to one another in stable sites, but it can also become a relational mechanism for mobilization during periods of contentious politics, as new groups are thrown together by increased interaction and uncertainty, thus discovering their common interests.
This too is a one-dimensional classification. And it appears to be intended to be exhaustive and mutually exclusive. But it isn’t clear to me that it succeeds in classifying all the mechanisms we might want to bring forward. Once again, this strikes me as a good beginning but not an exhaustive grouping of all social mechanisms.

My own preliminary grouping of mechanisms has even less structure (link). It groups mechanisms according to the subject matter or discipline from which they have emerged. But this does not serve to shed light on how these examples are similar or different from each other — one of the key purposes of a classification.

I think this is a very useful research activity, and Andrew Bennett has done a service to the theory of social mechanisms in putting forward this effort at classification. Let’s see what other schemes may be possible as well. A good scheme of classification may tell us something very important about the nature of how causation works in the social world.

What cities have in common

Images: Beijing (1900), Mexico City (2000), London (1600), Chicago (1930)

The “city” is a pretty heterogeneous category, encompassing human places that differ greatly with each other and possess a great deal of internal social heterogeneity as well. Size, population structure, economic or industrial specialization, forms of governance, and habitation and transportation structure all vary enormously across the population of cities. And so New York (2000), Chicago (1930), Rome (200), Mumbai (2008), Beijing (1800), Lagos (1970), London (1600), and Mexico City (1990) are all vastly different human agglomerations; and yet all are “cities”. Ancient, modern, medieval, developed, and underdeveloped — each of these places represents an urban concentration of population and habitation. (Here is an earlier posting that is relevant to the current topic.)

Given these many dimensions of difference, we can reasonably ask whether there are any shared urban characteristics or processes. Is there anything that a scientific or historical study of cities can discover? Is there a body of observation and discovery that might constitute the foundation for a sociology of cities?

Several points emerge quickly when we pose the question in these terms. First, a city is by definition a dense concentration of human inhabitants in a limited space. Human beings have material needs that must be satisfied daily: fresh water, food, shelter, clothing, and fuel, for example. Rural people can satisfy many of these needs directly through access to land, farms, and other natural resources. Urban populations are too dense to support individual or family self-sufficiency. So cities have this in common: they must have developed logistical systems for supplying residents with food, clean water, sanitation, and other basic necessities. This is the insight that motivated von Thünen in the development of central place theory (Isolated State: an English Edition of Der Isolierte Staat); equally it underlies William Cronon’s analysis of Chicago in Nature’s Metropolis: Chicago and the Great West and G. William Skinner’s analysis of urban hierarchies in China (link).

A second feature of cities is the unavoidable need for value-adding, non-agricultural production within the city. This means activities such as manufacturing, artisanal production, and the provision of services for pay. The residents of the city need to gain income in order to have “purchasing power” to acquire the necessities of life from the countryside. This implies a social organization that supports employment and occupations. So cities share this characteristic as well: they are grounded systems of production and exchange, permitting labor, production, circulation of commodities, and consumption. (Reasoning something like this underlay the analysis of Chicago into “ecological zones” pioneered by Chicago School sociologists Park and Burgess in The City: Suggestions for Investigation of Human Behavior in the Urban Environment.)

Given that cities are inherently spatial, the economic characteristics just mentioned also imply a circulation of persons throughout the city. And this implies that cities must possess some organized system of transportation. This may be walking pathways, roads for carriages, streetcars, buses, or subways and railroads. But economic activity and production requires circulation of people, and this implies urban transportation. But, as Sam Bass Warner showed in Streetcar Suburbs: The Process of Growth in Boston, 1870-1900, transport systems in turn create new patterns of residence and work in their wake.

A third common urban characteristic has to do with inequalities of power, influence, and property. Human populations seem always to embody significant inequalities along these lines. But advantages of power and wealth can be almost automatically transformed into facts of urban geography by the nomenklatura, the elites. So cities are likely to bear the signature of the social inequalities of wealth and power that are interwoven in their histories. The attractive locations for homes and gardens, preferred access to amenities such as water and roads, even locations favored from the point of view of pest and disease — these locations are likely to be stratified by wealth and power. (Engels’ description of the habitation patterns of bourgeoisie and proletariat in Birmingham and Manchester are illustrative; The Condition of the Working Class in England. Here’s a more developed discussion of Engels’ sociology of the city.)

Fourth, cities require formal systems of governance and law. Village society may succeed in establishing stable social order based on informal norms and processes. But cities are too large and complex to function as informal arrangements. Instead, there need to be ordinances for public health and safety, maintenance of public facilities, land use processes, and rules of public safety. Absent such governance, it is inconceivable that a city of one hundred thousand or a million would succeed in maintaining the delicate patterns of coordination needed for the continuing wellbeing of the residents.

So cities can be predicted to possess a variety of forms of social, political, economic, and geographical organization. Cities are not formless concentrations of humanity; rather, they are functional systems that can be investigated in depth. And here is the historical reality that permits this analysis to escape the charge of functionalism; the social systems that cities currently possess are the result of designs and adaptations of intelligent, strategic actors in the past. This means that they may be markedly non-optimal; they are likely to be skewed towards the interests and comfort of elites; but they are likely to work at some level of success.

These observations don’t exactly answer the original question in a tidy way; they don’t establish specific forms or characteristics that all cities share. But they do define a set of existential circumstances that cities must satisfy, and they pose in turn a series of questions about social organization and function that are likely to shed light on every city. We might look at this discussion as suggesting a matrix of analysis for all cities, corresponding to the large social needs mentioned here. How does a given city handle logistics, provisioning, local economic activity, transportation, land use, governance, public order, sanitation and health, and inequalities? What are the organizations and systems through which these central and inevitable tasks are accomplished? And then, perhaps, we may find a basis for classifying cities into large groups, based on the similarities that exist at this level of structure and organization. (For example, reasoning something like this leads G. William Skinner to distinguish between administrative and commercial cities in late Imperial China.)

A "peasant" revolution?

The Chinese communist party became a peasant revolutionary party after the spectacular destruction of the urban basis of the movement by Chiang Kai-shek in Shanghai in 1927. But who and what was a peasant, and how did this group become a revolutionary group?

In one sense the answer is obvious. China’s population consisted of a majority of poor farmers at the time of the collapse of the Qing dynasty, under a variety of forms of land tenure. They were poor, had little land, and were subject to exploitation by landlords, lenders, and the state. So we might say that this answers both questions: peasants were poor farmers, they were a large majority throughout China, and they were potentially revolutionary as a result of their poverty and exploitation. All that was needed was a party that could mobilize and activate them.

This response is too simple, however, for several reasons. First, the concept of peasant is a social and political construction. A “farmer” is an agricultural producer; but this fact about production status tells us little about how rural people defined their own social realities or the way that others defined them.

Second, the mobilization of “peasants” along class lines requires an organized political effort by a party that aggressively makes for the salience of class over other affinities — kinship, lineage, regional identity, or ethnicity. Marx expressed his assessment of the lack of solidarity of the French peasantry of the 1840s in these terms: “A small-holding, a peasant and his family; alongside them another small-holding, another peasant and another family. A few score of these make up a village, and a few score of villages make up a Department. In this way, the great mass of the French nation is formed by simple addition of homologous magnitudes, much as potatoes in a sack form a sack of potatoes” (Marx, The Eighteenth Brumaire of Louis Bonaparte). In order for a population to become a self-conscious identity group, it is necessary for a deliberate process of identity-formation to take place. The CCP worked single-mindedly to create this affinity with class identity throughout the 1920-30s in rural China. (Lucien Bianco, Peasants Without the Party: Grass-Root Movements in Twentieth-Century China; Odoric Wou, Mobilizing the Masses: Building Revolution in Henan.)

And third, it turns out that the politically defined status of “peasant” incorporated its own definition of internal inequality — between rich, middle, and poor peasants. These terms of internal differentiation played a prominent role in the mobilization strategies and policies of the CCP in its drive to revolution. The CCP emphasized conflicts within the class of peasants as much as the conflicts between peasants and others.

The mobilization strategies of the CCP of the 1930s were aimed at creating a large and energized supporting population of poor and middle peasants. They pursued this goal by recruiting local cadres who could communicate the party message to their intended supporters and by offering a program of land reform and social reversal that would strongly appeal to this group. Their efforts were successful in several important base areas, and the CCP was in fact able to cultivate a loyal base among poor and middle peasants. Moreover, this group increasingly provided recruits for middle and higher positions of leadership in the military and political organizations of the party.

So we might say that the peasant movement was in fact created and shaped by CCP doctrines in the 1930s as a contingent but portentious social force in China. And for the first 30 years of the Chinese communist state serious efforts were made to retain the loyalties of this social segment.

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.

Generalizations about cluster items

What is the basis of classification of items into groups? And how do classifications fit into scientific inquiry and theory? First, what different types of classification are there?

Essential: The items may share a common defining characteristic (e.g. “liquid”, “metal”)
— Etiological: The items may share a common cause (e.g. “viral illness”)
— Structural: The items may share a common underlying structure (e.g. “protein”, “elm”)
— Functional: The items may share a common function (e.g. “weapon”, “school”)

Non-essential: The items may lack necessary and sufficient conditions but share some overlapping characteristics.
— Symptomatic: The items may share a set of observable characteristics or symtoms (e.g. “pneumonia”, “schizophrenia”)
— Cluster: the items may share some among a list of characteristics (e.g. “game”, “leader”)

(It is a bit curious to observe that this amounts to a classification of systems of classification.)

Now let’s consider some social science terms and see where they fall in this scheme: riot, civil war, bicameral legislature, ethnic group, democracy, charismatic leader, financial city, working class organization.

Several of these concepts are symtom or cluster concepts: riot, democracy. Several others are etiological or structural: civil war, bicameral legislature, financial city. One combines structural with functional criteria: bicameral legislature.

Now suppose we have identified a set of things as being “democracies”. They share some among a set of features that are associated with democracy, and there is no set of features shared by all instances. What kinds of social science inquiry can we do? First, we can do comparisons within the group of democracies we have identified; we can look for similarities and differences across the group. And second, we can ask whether membership in this group is associated with membership in some other group beyond what chance would predict. In other words, we can consider whether there are true statements like “all democracies are X” or “most democracies are Y.”

It is not the case that “all pneumonias respond to penicillin”–for the reason that there are two causal and structural kinds of pneumonia, and only one of these involves organisms treatable with penicillin. The causal heterogeneity of this group means that strong generalizations are difficult or impossible here.

The concepts of riot, revolution, and democracy are similarly heterogeneous, both causally and structurally. So we should expect only weak generalizations across this group and other social charactistics. On the other hand, the tools of social comparison are most valuable here. We can discover through additional comparative work within the category, whether there are similar structural and causal processes at work among instances of this concept.