Co-citation networks in philosophy

I took twenty years worth of articles from four major philosophy journals and generated a network from it based on the citations contained in those articles. The substantive idea is as follows. An academic discipline is a sort of exclusive, ongoing conversation. The conversation is carried on, amongst other settings, through books and articles. In many disciplines there are a few high-status general-interest journals that claim to publish the best work in the field. Particular members of the field will of course disagree about how true that is, but for my purposes the point is just a descriptive one. I am interested in what high-status actors in a field are talking about, and one source of information about this is what gets published in high-prestige journals that claim to represent the core of the discipline.--Kieran Healy

For a fantastic visual representation of Healy's results, see here. ("The graph shows co-citation patterns for the 500 most-cited items over the past twenty years, based on the articles published in our four journals.") The main results are instructive, but not surprising:

"[A] The core of the graph is a group of highly-cited items clustered around the most-cited item in the dataset: David Lewis’s 1986 book, On the Plurality of Worlds....[B] A second large cluster of citations focus on epistemology. Here the key works are by Tim Williamson (2000), Keith de Rose (1995), and Jim Pryor (2000). Interestingly, [C] there is a paper by Lewis here as well (Lewis 1996)....this is going to be a common occurrence....[D] there seem to be two separate clusters in the philosophy of mind...The first seems to be about consciousness...the second...is arguing with Jerry Fodor...[E] Work in ethics, metaethics, and political philosophy forms a component disconnected from the main graph."

Below the fold analysis (by Schliesser not Healy).

First, the four journals are: "Nous, the Journal of Philosophy, the Philosophical Review, and Mind."  Now, let's stipulate these are the right kind of journals for the question Healy is asking. Even so, these journals also introduce some selection biases (by definition/stipulation), some obvious some more subtle: (i) there will be almost no continental philosophy (of the SPEP kind or of the Leiter kind); (ii) for most of the period covered by Healy, at least three of these journals have been notorious for being very slow; (iii) for a chunk of the period, several of these journals did not really practice blind double or triple blind review and (perhaps, to this day) reflect the institutional commitments of particular departments. 

Now, given that Healy understands an "academic discipline as a sort of exclusive, ongoing conversation," (i)-(iii) may not be a problem at all. There is going to be exclusivity anyway, so for the purposes of Healy's analysis it does not matter if the exclusivity is due to some kind of intellectual Mafia, journal capture, or social networking.  But within the discipline (i.e., those of us studied by Healy) journal capture can be existential. As Brian Leiter put it last week in a different context, "surely the prospect of an APA-approved journal will bring out “special interest” lobbying in its worst forms."

Even if we leave aside journal capture,  (ii) and (iii) suggest that the journals may also be lagging indicators of what the discipline is "talking about." Don't get me wrong: I have no doubt that we live in the age of Lewis substantially and methodologically. But to reveal my biases: is Fodor really still central in philosophy of mind? I suspect less so. In 1998 I could have started writing a dissertation on Fodor (who, of course, is a larger-than-life, ebullient and argumentative figure), but it seemed to me that most of the exciting responses had already appeared (and nothing I have heard since has made me change my mind). Now it's possible, of course, that the cognitive revolution need not change the centrality of the philosophical issues that Fodor grappled with, but I do wonder if the citations to Fodor's work from the 80s and 90s are not totemic. So, while I grant that Healy's approach is "usually informative about what’s happening in a field," it doesn't mean that they are fine-grained enough about what people are excited about (perhaps, blog conversations, or invitations to workshop patterns may be more informative).

Okay, I could be ALL wrong about the centrality of Fodor and excitement about his granny.  Even so if the journals are lagging and selective indicators there is a genuine a concern: given that in contested areas and scarce resources any 'objective' index and metric can and often will be used to further some decision procedure, the Healy-index is likely to create more status quo bias. 

Second, it is striking how closed the large communities are. Only work by Lewis (PhD Harvard, mostly Princeton) and Stalnaker (PhD Princeton; Cornell/MIT) bridges (in Healy's sense) the metaphysics and epistemology clusters. Fair enough. (It reminds us of the centrality of modality.) Both are genuine philosopher's philosophers whose work holds up very well after repeat reading.  One wonders, of course, to what degree citations are also influenced by PhD Supervisor/Student relations as well as more generally the reading/teaching habits of charismatic figures at one's PhD granting institution. In a twenty year window such features are to be expected not to be irrelevant. Hopefully, Healy's follow-up research will explore such issues.

Third, after a century, analytical philosophy has not generated a single figure that is central to both M&E as well as value. This was part of the 'problems-focused-plan', as it were. But if there is even some trade-off between systematicity and focus, there ought to be some low-hanging systematic fruit. The question is, of course, if that fruit can be published in the Healy four.

Okay, that's enough for now; I love Healy's work, so I am sure to return to it. Obviously, Jerry Fodor and granny fans are encouraged to complain.