Tuesday, July 28, 2015

Supervenience, isomers, and social isomers

A prior post focused on the question of whether chemistry supervenes upon physics, and I relied heavily on R. F. Hendry's treatment of the way that quantum chemistry attempts to explain the properties of various molecules based on fundamentals of quantum mechanics. This piece raised quite a bit of great discussion, from people who agree with Hendry and those who disagree.

It occurs to me that there is a simpler reason for thinking that chemistry fails to supervene upon the physics of atoms, however, which does not involve the subtleties of quantum mechanics. This is the existence of isomers for various molecules. An isomer is a molecule with the same chemical composition as another but a different geometry and different chemical properties. From the facts about the constituent atoms we cannot infer uniquely what geometry a molecule consisting of these atoms will take. Instead, we need more information external to the physics of the atoms involved; we need an account of the path of interactions that the atoms took in "folding" into one isomer or the other. Therefore chemistry does not supervene upon the quantum-mechanical or physical properties of atoms alone.

For example, the properties of the normal prion protein and its isomer, infectious prion protein, are not fixed by the constituent elements; the geometries associated with these two compounds result from other causal influences. The constituent elements are compatible with both non-equivalent expressions. The prion molecules do not supervene upon the properties of the constituent elements. The question of which isomer emerges is one of a contingent path dependent process.

It is evident that this is not an argument that chemistry does not supervene upon physics more generally, since the history of interactions through which a given isomer emerges is itself a history of physical interactions. But it does appear to be a rock-solid refutation of the idea that molecules supervene upon the atoms of which they are constituted.

Significantly, this example appears to have direct implications for the relation between social facts and individual actors. If we consider the possibility of "social isomers" -- social structures consisting of exactly similar actors but different histories and different configurations and causal properties in the present -- then we also have a refutation of the idea that social facts supervene upon the actors of which they are constituted. Instead, we would need to incorporate the "path-dependent" series of interactions that led to the formation of one "geometry" of social arrangements rather than another, as well as to the full suite of properties associated with each individual actor. So QED -- social structures do not supervene on the features of the actors. And if some of the events that influence the emergence of one social structure rather than another are stochastic or random -- one social isomer instead of its compositional equivalent -- then at best social structures supervene on individuals conjoined with chance events in a path-dependent process.

There has been much discussion of the question of multiple realizability -- that one higher-level structure may correspond to multiple underlying configurations of components and processes. But so far as I have been able to see, there has been no discussion of the converse possibility -- multiple higher-level structures corresponding to a single underlying configuration. And yet this is precisely what is the case in chemistry for isomers and in the hypothetical but plausible possibility sketched here for "social isomers". This is indeed the key finding of the discovery of path-dependencies in social outcomes.

Sunday, July 26, 2015

Is chemistry supervenient upon physics?

Many philosophers of science and physicists take it for granted that "physics" determines "chemistry". Or in terms of the theory of supervenience, it is commonly supposed that the domain of chemistry supervenes upon the domain of fundamental physics. This is the thesis of physicalism: the idea that all causation ultimately depends on the causal powers of the phenomena described by fundamental physics.

R. F. Hendry takes up this issue in his contribution to Davis Baird, Eric Scerri, and Lee McIntyre's very interesting volume, Philosophy of Chemistry. Hendry takes the position that this relation of supervenience does not obtain; chemistry does not supervene upon fundamental physics.

Hendry points out that the dependence claim depends crucially on two things: what aspects of physics are to be considered? And second, what kind of dependency do we have in mind between higher and lower levels? For the first question, he proposes that we think about fundamental physics -- quantum mechanics and relativity theory (174). For the second question, he enumerates several different kinds of dependency: supervenience, realization, token identity, reducibility, and derivability (175). In discussing the macro-property of transparency in glass, he cites Jaegwon Kim in maintaining that transparency in glass is "nothing more" than the features of the microstructure of glass that permit it to transmit light. But here is a crucial qualification:
But as Kim admits, this last implication only follows if it is accepted that “the microstructure of a system determines its causal/nomic properties” (283), for the functional role is specified causally, and so the realizer’s realizing the functional property that it does (i.e., the realizer–role relation itself) depends on how things in fact go in a particular kind of system. For a microstructure to determine the possession of a functional property, it must completely determine the causal/nomic properties of that system. (175)
Hendry argues that the key issue underlying claims of dependence of B upon A is whether there is downward causation from the level of chemistry (B) to the physical level (A); or, on the contrary, is physics "causally complete". If the causal properties of the higher level are fully fixed by the causal properties of the underlying level, then supervenience is possible; but if the higher level has causal properties that permit influence on the lower level, then supervenience is not possible.

In order to gain insight into the specific issues arising concerning chemistry and physics, Hendry makes use of the "emergentist" thinking associated with C.D. Broad. He finds that Broad offers convincing arguments against "Pure Mechanism", the view that all material things are determined by the micro-physical level (177). Here are Broad's two contrasting possibilities for understanding the relations between higher levels and the physical micro-level:
(i) On the first form of the theory the characteristic behavior of the whole could not, even in theory, be deduced from the most complete knowledge of the behavior of its components, taken separately or in other combinations, and of their proportions and arrangements in this whole . . .
(ii) On the second form of the theory the characteristic behavior of the whole is not only completely determined by the nature and arrangements of its components; in addition to this it is held that the behavior of the whole could, in theory at least, be deduced from a sufficient knowledge of how the components behave in isolation or in other wholes of a simpler kind (1925, 59). [Hendry, 178]
The first formulation describes "emergence", whereas the second is "mechanism". In order to give more contemporary expression to the two views Hendry introduces the key concept of quantum chemistry, the Hamiltonian for a molecule. A Hamiltonian is an operator describing the total energy of a system. A "resultant" Hamiltonian is the operator that results from identifying and summing up all forces within a system; a configurational Hamiltonian is one that has been observationally adjusted to represent the observed energies of the system. The first version is "fundamental", whereas the second version is descriptive.

Now we can pose the question of whether chemistry (behavior of molecules) is fixed by the resultant Hamiltonian for the components of the atoms involved (electrons, protons, neutrons) and the forces that they exert on each other. Or, on the other hand, does quantum chemistry achieve its goals by arriving at configurational Hamiltonians for molecules, and deriving properties from these descriptive operators? Hendry finds that the latter is the case for existing derivations; and this means that quantum chemistry (as it is currently practiced) does not derive chemical properties from fundamental quantum theory. Moreover, the configuration of the Hamiltonians used requires abstractive description of the hypothesized geometry of the molecule and the assumption of the relatively slow motion of the nucleus. But this is information at the level of chemistry, not fundamental physics. And it implies downward causation from the level of chemical structure to the level of fundamental physics.
Furthermore, to the extent that the behavior of any subsystem is affected by the supersystems in which it participates, the emergent behavior of complex systems must be viewed as determining, but not being fully determined by, the behavior of their constituent parts. And that is downward causation. (180)
So chemistry does not derive from fundamental physics. Here is Hendry's conclusion, supporting pluralism and anti-reductionism in the case of chemistry and physics:
On the other hand is the pluralist version, in which physical law does not fully determine the behavior of the kinds of systems studied by the special sciences. On this view, although the very abstractness of the physical theories seems to indicate that they could, in principle, be regarded as applying to special science systems, their applicability is either trivial (and correspondingly uninformative), or if non-trivial, the nature of scientific inquiry is such that there is no particular reason to expect the relevant applications to be accurate in their predictions.... The burden of my argument has been that strict physicalism fails, because it misrepresents the details of physical explanation (187)
Hendry's argument has a lot in common with Herbert Simon's arguments about system complexity (link) and with Nancy Cartwright's arguments about the limitations of (real) physics' capability of representing and calculating the behavior of complex physical systems based on first principles (link). In each case we get a pragmatic argument against reductionism, and a weakened basis for assuming a strict supervenience relation between higher-level structures and a limited set of supposedly fundamental building blocks. What is striking is that Hendry's arguments undercut the reductionist impulse at what looks like its most persuasive juncture -- the relationship between quantum physics and quantum chemistry.

Thursday, July 23, 2015

Microfoundations for rules and ascriptions

One of the more convincing arguments for the existence of social facts that lie above the level of individual actors is the social reality of rules and ascriptive identities. Bob and Alice are married by Reverend Green at 7 pm, July 1, 2015. The social fact that Bob and Alice are now married is not simply a concatenation of facts about their previous motions, beliefs, and utterances. Rather, it depends also on several trans-individual circumstances: first, that their behaviors and performances conform to a set of legal rules governing marriage (e.g., that neither was married at the time of their marriage to each other, or that they had secured a valid marriage license from the county clerk); and second, that various actors in the event possess a legal identity and qualification that transcend the psychological and observational properties they possess. (Reverend Green is in fact a legally qualified agent of a denomination that gives him the legal authority to perform the act of marriage between two qualified adults.) If Bob has permanently forgotten his earlier marriage in a moment of intoxication to Francine, or if Reverend Green is an imposter, then the correct performance of each of the actions of the ceremony nonetheless fails to secure the legal act of "marriage". Bob and Alice are not married if these prior conditions are not satisfied. So the social fact that Bob and Alice are married does not depend exclusively on their performance of a specific set of actions and utterances.

Is this kind of example a compelling refutation of the thesis of ontological individualism (as Brian Epstein believes it is; link)? John Searle thinks that facts like these are fundamentally important in the social world; he refers to them as "status functions" (link). And Epstein's central examples of supra-individual social facts have to do with membership and ascriptive status. However, several considerations suggest to me that the logical status of rules and ascriptions does not have a lot of importance for our understanding of the ontology of the social world.

First, ascriptive properties are ontologically peculiar. They are dependent upon presuppositions and implicatures that cannot be fully validated in the present. Consider the contrast between these two statements about Song Taizu, founder of the Song Dynasty: "Song was a military and political mastermind" and "Song was legitimate emperor of China." The former statement is a factual statement about Song's embodied characteristics and talents. The latter is a complex historical statement with debatable presuppositions. The truth of the statement turns on our interpretation of the legal status of the seven-year-old "Emperor" whom he replaced. It is an historical fact that Song ruled long and effectively as chief executive; it is a legal abstraction to assert that he was "legitimate emperor".

Second, it is clear that systems of rules have microfoundations if they are causally influential. There are individuals and concrete institutions who convey and interpret the rules; there are prosecutors who take offenders to task; there are libraries of legal codes and supporting interpretations that constitute the ultimate standard of adjudication when rules and behavior come into conflict. And individuals have (imperfect) grasp of the systems of rules within which they live and act -- including the rule that specifies that ignorance is no excuse for breach of law. So it is in fact feasible to sketch out the way that a system of law or a set of normative rules acquires social reality and becomes capable of affecting behavior.

Most fundamentally, I would like to argue that our interest is not in social facts simpliciter, but in facts that have causal and behavioral consequences. We want to know how social agglomerates behave, and in order to explain these kinds of facts, we need to know how the actors who make them up think, deliberate, and act. Whether Alice and Bob are really married is irrelevant to their behavior and that of the individuals who surround them. Instead, what matters is how they and others represent themselves. So the behaviorally relevant question is this: do Alice, Bob, Reverend Green, and the others with whom they interact believe that they are married? So the behaviorally relevant content of "x is married to y" is restricted to the beliefs and attitudes of the individuals involved -- not the legalistic question of whether their marriage satisfied current marriage laws.

To be sure, if a reasonable doubt is raised about the legal validity of their marriage, then their beliefs (and those of others) will change. Assuming they understand marriage in the same way as we do -- "two rationally competent individuals have undertaken legally specified commitments to each other, through a procedurally qualified enactment" -- then doubts about the presuppositions will lead them to recalculate their current beliefs and status as well. They will now behave differently than they would have behaved absent the reasonable doubts. But what is causally active here is not the fact that they were not legally married after all; it is their knowledge that they were not legally married.

So is the fact that Bob and Alice are really married a social fact? Or is it sufficient to refer to the fact that they and their neighbors and family believe that they are married in order to explain their behavior? In other words, is it the logical fact or the epistemic fact that does the causal work? I think the latter is the case, and that the purely ascriptive and procedural fact is not itself causally powerful. So we might turn the tables on Epstein and Searle, and consider the idea that only those social properties that have appropriate foundations at the level of socially situated individuals should be counted as real social properties.

Wednesday, July 15, 2015

Supervenience and the social: Epstein's critique

Does the social world supervene upon facts about individuals and the physical environment of action? Brian Epstein argues not in several places, most notably in "Ontological Individualism Reconsidered" (2009; link). (I plan to treat Epstein's more recent arguments in his very interesting book The Ant Trap: Rebuilding the Foundations of the Social Sciences in a later post.) The core of his argument is the idea that there are other factors influencing social facts besides facts about individuals. Social facts then fail to supervene in the strict sense: they depend on facts other than facts about individuals. There are indeed differences at the level of the social that do not correspond to a difference in the facts at the level of the individual. Here is how Epstein puts the core of his argument:
My aim in this paper is to challenge this [the idea that individualism is simply the denial of spooky social autonomy]. But ontological individualism is a stronger thesis than this, and on any plausible interpretation, it is false. The reason is not that social properties are determined by something other than physical properties of the world. Instead it is that social properties are often determined by physical ones that cannot plausibly be taken to be individualistic properties of persons. Only if the thesis of ontological individualism is weakened to the point that it is equivalent to physicalism can it be true, but then it fails to be a thesis about the determination of social properties by individualistic ones. (3)
And here is how Epstein formulates the claim of weakly local supervenience of social properties upon individual properties:
Social properties weakly locally supervene on individualistic properties if and only if for any possible world w and any entities x and y in w, if x and y are individualistically indiscernible in w, then they are socially indiscernible in w. Two objects are individualistically- or socially-indiscernible if and only if they are exactly like with respect to every individualistic property or every social property, respectively. (9)
The causal story for supervenience of the social upon the individual perhaps looks like this:

The causal story for non-supervenience that Epstein tells looks like this:

In this case supervenience fails because there can be differences in S without any difference in I (because of differences in O).

But maybe the situation is even worse, as emergentists want to hold:

Here supervenience fails because social facts may be partially "auto-causal" -- social outcomes are partially influenced by differences in social facts that do not depend on differences in individual facts and other facts.

In one sense Epstein's line of thought is fairly easy to grasp. The outcome of a game of baseball between the New York Yankees and the Boston Red Sox depends largely on the actions of the players on the field and in the dugout; but not entirely and strictly. There are background facts and circumstances that also influence the outcome but are not present in the motions and thoughts of the players. The rules of baseball are not embodied on the field or in the minds of the players; so there may be possible worlds in which the same pitches, swings, impacts of bats on balls, catches, etc., occur; and yet the outcome of the game is different. The Boston pitcher may be subsequently found to be ineligible to play that day, and the Red Sox are held to forfeit the game. The rule in our world holds that "tie goes to the runner"; whereas in alto-world it may be that the tie goes to the defensive team; and this means that the two-run homer in the ninth does not result in two runs, but rather the final out. So the game does not depend on the actions of the players alone, but on distant and abstract facts about the rules of the game.

So what are some examples of "other facts" that might be causally relevant to social outcomes? The scenario offered here captures some of the key "extra-individual" facts that Epstein highlights, and that play a key role in the social ontology of John Searle: situating rules and interpretations that give semantic meaning to behaviors. Epstein highlights facts that determine "membership" in meaningful social contexts: being President, being the catcher on the Boston Red Sox. Both Epstein and Searle emphasize that there are a wide range of dispersed facts that must be true in order for Barack Obama to be President and Ryan Hanigan to be catcher. This is not a strictly "individual-level" fact about either man. Epstein quotes Gregorie Currie on this point: "My being Prime Minister ... is not just a matter of what I think and do; it depends on what others think and do as well. So my social characteristics are clearly not determined by my individual characteristics alone" (11).

So, according to Epstein, local supervenience of the social upon the individual fails. What about global supervenience? He believes that this relation fails as well. And this is because, for Epstein, "social properties are determined by physical properties that are not plausibly the properties of individuals" (20). These are the "other facts" in the diagrams above. His simplest illustration is this: without cellos there can be no cellists (24). And without hanging chads, George W. Bush would not have been President. And, later, one can be an environmental criminal because of a set of facts that were both distant and unknown to the individual at the time of a certain action (33).

Epstein's analysis is careful and convincing in its own terms. Given the modal specification of the meaning of supervenience (as offered by Jaegwon Kim and successors), Epstein makes a powerful case for believing that the social does not supervene upon the individual in a technical and specifiable sense. However, I'm not sure that very much follows from this finding. For researchers within the general school of thought of "actor-centered sociology", their research strategy is likely to remain one that seeks to sort out the mechanisms through which social outcomes of interest are created as a result of the actions and interactions of individuals. If Epstein's arguments are accepted, that implies that we should not couch that research strategy in terms of the idea of supervenience. But this does not invalidate the strategy, or the broad intuition about the relation between the social and the actions of locally situated actors upon which it rests. These are the intuitions that I try to express through the idea of "methodological localism"; link, link. And since I also want to argue for the possibility of "relative explanatory autonomy" for facts at the level of the social (for example, features of an organization; link), I am not too troubled by the failure of a view of the social and individual that denies strict determination of the former by the latter. (Here is an earlier post where I wrestled with the idea of supervenience; link.)

Sunday, July 5, 2015

Goffman on close encounters

image: GIF from D. Witt (link)

George Herbert Mead's approach to social psychology is an important contribution to the new pragmatism in sociology (link). Mead puts forward in Mind, Self, and Society: From the Standpoint of a Social Behaviorist a conception of the self that is inherently social; the social environment is prior to the individual, in his understanding. And what this means is that individuals acquire habits, attitudes, and ways of thinking through their interactions in the social environments in which they live and grow up. The individual's social conduct is built up out of the internalized traces of the practices, norms, and orientations of the people around him or her.

Erving Goffman is one of the sociologists who has given the greatest attention to the role of social norms in ordinary social interaction. One of his central themes is a focus on face-to-face interaction. This is the central topic in his book, Interaction Ritual - Essays on Face-to-Face Behavior. So rereading Interaction Ritual is a good way to gain some concrete exposure to how some sociologists think about the internalized norms and practices that Mead describes.

Goffman's central concern in this book is how ordinary social interactions develop. How do the participants shape their contributions in such a way as to lead to a satisfactory exchange? The ideas of "line" and "face" are the central concepts in this volume. "Line" is the performative strategy the individual has within the interaction. "Face" is the way in which the individual perceives himself, and the way he perceives others in the interaction to perceive him. Maintaining face invokes pride and honor, while losing face invokes shame and embarrassment. So a great deal of the effort extended by the actor in social interactions has to do with maintaining face -- what Goffman refers to as "face-work". Here are several key descriptions of the role of face-work in ordinary social interactions:
By face-work I mean to designate the actions taken by a person to make whatever he is doing consistent with face. (12)
The members of every social circle may be expected to have some knowledge of face-work and some experience in its use. In our society, this kind of capacity is sometimes called tact, savoir-faire, diplomacy, or social skill. (13)
A person may be said to have, or be in, or maintain face when the line he effectively takes presents an image of him that is internally consistent, that is supported by judgment and evidence conveyed by other participants, and that is confirmed by evidence conveyed through and personal agencies in the situation. (6-7)
So Goffman's view is that the vast majority of face-to-face social interactions are driven by the logic of the participants' conceptions of "face" and the "lines" that they assume for the interaction. Moreover, Goffman holds that in many circumstances, the lines available for the person in the circumstance are defined by convention and are relatively few. This entails that most interactional behavior is scripted and conventional as well. This line of thought emphasizes the coercive role played by social expectations in face to face encounters. And it dovetails with the view Goffman often expresses of action as performative, and self as dramaturgical.

The concept of self is a central focus of Mead's work in MSS. Goffman too addresses the topic of self:
So far I have implicitly been using a double definition of self: the self as an image pieced together from the expressive implications of the full flow of events in an undertaking; and the self as a kind of player in a ritual game who copes honorably or dishonorably, diplomatically or undiplomatically, with the judgmental contingencies of the situation. (31)
Fundamentally, Goffman's view inclines against the notion of a primeval or authentic self; instead, the self is a construct dictated by society and adopted and projected by the individual.
Universal human nature is not a very human thing. By acquiring it, the person becomes a kind of construct, build up not from inner psychic propensities but from moral rules that are impressed upon him from without. (45)
Moreover, Goffman highlights the scope of self-deception and manipulation that is a part of his conception of the actor:
Whatever his position in society, the person insulates himself by blindnesses, half-truths, illusions, and rationalizations. He makes an "adjustment" by convincing himself, with the tactful support of his intimate circle, that he is what he wants to be and that he would not do to gain his ends what the others have done to gain theirs. (43)
One thing that is very interesting about this book is the concluding essay, "Where the Action Is". Here Goffman considers people making choices that are neither prudent nor norm guided. He considers hapless bank robbers, a black journalist mistreated by a highway patrolman in Indiana, and other individuals making risky choices contrary to the prescribed scripts. In this setting, "action" is an opportunity for risky choice, counter-normative choice, throwing fate to the wind. And Goffman thinks there is something inherently attractive about this kind of risk-taking behavior.

Here Goffman seems to be breaking his own rules -- the theoretical ones, anyway. He seems to be allowing that action is sometimes not guided by prescriptive rules of interaction, and that there are human impulses towards risk-taking that make this kind of behavior relatively persistent in society. But this seems to point to a whole category of action that is otherwise overlooked in Goffman's work -- the actions of heroes, outlaws, counter-culture activists, saints, and ordinary men and women of integrity. In each case these actors are choosing lines of conduct that break the norms and that proceed from their own conceptions of what they should do (or want to do).  In this respect the pragmatists, and Mead in particular, seem to have the more complete conception of the actor, because they leave room for spontaneity and creativity in action, as well as a degree of independence from coercive norms of behavior. Goffman opens this door with his long concluding essay here; but plainly there is a great deal more that can be said on this subject.

The 1955 novel and movie Man in the Grey Flannel Suit seems to illustrate both parts of the theory of action in play here -- a highly constrained field of action presented to the businessman (played by Gregory Peck), punctuated by occasional episodes of behavior that break the norms and expectations of the setting. Here is Tom Rath speaking honestly to his boss. (The whole film is available on YouTube.)

Thursday, July 2, 2015

Deliberative democracy and the age of social media

Several earlier posts have focused on the theory of deliberative democracy (link, link, link). The notion is that political decision-making can be improved by finding mechanisms for permitting citizens to have extended opportunities for discussion and debate over policies and goals. The idea appeals to liberal democratic theorists in the tradition of Rousseau -- the idea that people's political preferences and values can become richer and more adequate through reasoned discussion in a conversation of equals, and political decisions will be improved through such a process. This idea doesn't quite equate to the wisdom of the crowd; rather, individuals become wiser through their interactions with other thoughtful and deliberative people, and the crowd's opinions improve as a result.

Here is the definition of deliberative democracy offered by Amy Gutmann and Dennis Thompson in Why Deliberative Democracy? (2004):
Most fundamentally, deliberative democracy affirms the need to justify decisions made by citizens and their representatives. Both are expected to justify the laws they would impose on one another. In a democracy, leaders should therefore give reasons for their decisions, and respond to the reasons that citizens give in return... The reasons that deliberative democracy asks citizens and their representatives to give should appeal to principles that individuals who are trying to find fair terms of cooperation cannot reasonably reject. (3)
All political reasoning inherently involves an intermingling of goals, principles, and facts. What do we want to achieve? What moral principles do we respect as constraints on political choices? How do we think about the causal properties of the natural and social world in which we live? Political disagreement can derive from disagreements in each of these dimensions; deliberation in principle is expected to help citizens to narrow the range of disagreements they have about goals, principles, and facts. And traditional theorists of deliberative democracy, from the pre-Socratics to Gutmann, Thompson, or Fishkin, believe that it is possible for people of good will to come to realize that the beliefs and assumptions they bring to the debate may need adjustment.

But something important has changed since the 1990s when a lot of discussions of deliberative democracy took place. This is the workings of social media -- blogs, comments, Twitter discussions, Facebook communities. Here we have millions of people interacting with each other and debating issues -- but we don't seem to have a surge of better or more informed thinking about the hard issues. On the one hand, we might hope that the vast bandwidth of debate and discussion of issues, involving enormous numbers of the world's citizens, would have the effect of deepening the public's understanding of complex issues and policies. And on the other hand, we seem to have the evidence of continuing superficial thinking about issues, hardening of ideological positions, and reflexive habits of racism, homophobia, and xenophobia. The Internet seems to lead as often to a hardening and narrowing of attitudes as it does to a broadening and deepening of people's thinking about the serious issues we face.

So it is worth reflecting on what implications are presented to our ideas about democracy by the availability of the infrastructure of social media. It was observed during the months of the Arab Spring that Twitter and other social media platforms played a role in mobilization of groups of people sharing an interest in reform. And Guobin Yang describes the role that the Internet has played in some areas of popular activism in China (link). This is a little different from the theory of deliberative democracy, however, since mobilization is different from deliberative value-formation. The key question remains unanswered: can the quality of thinking and deliberation of the public be improved through the use of social media? Can the public come to a better understanding of issues like climate change, health care reform, and rising economic inequalities through the debates and discussions that occur on social media? Can our democracy be improved through the tools of Twitter, Facebook, or Google? So far the evidence is not encouraging; it is hard to find evidence suggesting a convergence of political or social attitudes deriving from massive use of social media. And the most dramatic recent example of change in public attitudes, the sudden rise in public acceptance of single-sex marriage, does not seem to have much of a connection from social media.

Here is a very interesting report by the Pew Foundation on the political segmentation of the world of Twitter (link). The heart of their findings is that Twitter discussions of politics commonly segment into largely distinct groups of individuals and websites (link).
Conversations on Twitter create networks with identifiable contours as people reply to and mention one another in their tweets. These conversational structures differ, depending on the subject and the people driving the conversation. Six structures are regularly observed: divided, unified, fragmented, clustered, and inward and outward hub and spoke structures. These are created as individuals choose whom to reply to or mention in their Twitter messages and the structures tell a story about the nature of the conversation.
If a topic is political, it is common to see two separate, polarized crowds take shape. They form two distinct discussion groups that mostly do not interact with each other. Frequently these are recognizably liberal or conservative groups. The participants within each separate group commonly mention very different collections of website URLs and use distinct hashtags and words. The split is clearly evident in many highly controversial discussions: people in clusters that we identified as liberal used URLs for mainstream news websites, while groups we identified as conservative used links to conservative news websites and commentary sources. At the center of each group are discussion leaders, the prominent people who are widely replied to or mentioned in the discussion. In polarized discussions, each group links to a different set of influential people or organizations that can be found at the center of each conversation cluster.
And here is the authors' reason for thinking that the clustering of Twitter conversations is important:
Social media is increasingly home to civil society, the place where knowledge sharing, public discussions, debates, and disputes are carried out. As the new public square, social media conversations are as important to document as any other large public gathering. Network maps of public social media discussions in services like Twitter can provide insights into the role social media plays in our society. These maps are like aerial photographs of a crowd, showing the rough size and composition of a population. These maps can be augmented with on the ground interviews with crowd participants, collecting their words and interests. Insights from network analysis and visualization can complement survey or focus group research methods and can enhance sentiment analysis of the text of messages like tweets.
Here are examples of "polarized crowds" and "tight crowds":

There is a great deal of research underway on the network graphs that can be identified within social media populations. But an early takeaway seems to be that segmentation rather than convergence appears to be the most common pattern. This seems to run contrary to the goals of deliberative democracy. Rather than exposing themselves to challenging ideas from people and sources in the other community, people tend to stay in their own circle.

So this is how social media seem to work if left to their own devices. Are there promising examples of more intentional uses of social media to engage the public in deeper conversations about the issues of the day? Certainly there are political organizations across the spectrum that are making large efforts to use social media as a platform for their messages and values. But this is not exactly "deliberative". What is more intriguing is whether there are foundations and non-profit organizations that have specifically focused on creating a more deliberative social media community that can help build a broader consensus about difficult policy choices. And so far I haven't been able to find good examples of this kind of effort.

(Josh Cohen's discussion of Rousseau's political philosophy is interesting in the context of fresh thinking about deliberation and democracy; link. And Archon Fung and Erik Olin Wright's collection of articles on democratic innovation, Deepening Democracy: Institutional Innovations in Empowered Participatory Governance (The Real Utopias Project) (v. 4), is a very good contribution as well.)