I'm with Brad DeLong on this. The belief that intellectual work 
proceeds linearly, involving as citation studies assume, links of 
similar kinds, is simply contrary to both fact and sense and is 
contrary to how "science" works. As Bruno Latour once wrote:
"since the status of a claim depends on later users' insertions, what 
if there are no later users whatsoever? This is the point that people 
who never come close to the fabrication of science have the greatest 
difficulty in grasping. They imagine that all scientific articles are 
equal and arrayed in lines like soldiers, to be inspected one by one. 
However most papers are never read at all. No mater what a paper did 
to the former literature, if no one else does anything else with it, 
then it is as if it had never existed at all. You may have written a 
paper that settles a fierce controversy once and for all, but if 
readers ignore it it cannot be turned into a fact; it simply cannot." 
[Science in Action, p. 40]

Years ago I tried to say this with respect to HE in:
"Is 'Is a Precursor of' a Transitive Relation," E. R. Weintraub, 
South Atlantic Quarterly 94.2 (1995): 571-589. Reprinted (in slightly 
different form) in Andrea Salanti and Ernesto Screpanti (eds.), 
Pluralism in Economics, Cheltenham, UK: Edward Elgar, 1996, 212-226; 
Reprinted in Barbara Herrnstein Smith and Arkady Plotnitsky, 
Mathematics, Science, and Cultural Theory, Durham: Duke University 
Press, 1997, 173-188.


E. Roy Weintraub