In the Mangle of Practice Andrew Pickering, a former physicist (particle theoretician) turned historian,  develops a dialectic of resistance and accommodation he calls the mangle.  The mangle accounts for the development of scientific theories and practices which are linked to performance and production but not to a representational theory of reality.  The mangle theory is scale invariant, and indeed, Pickering appears to think it is robust enough to serve as a Theory of Everything.

What is the mangle, and how does it "work?"  First, it is important to grasp material agency in relation to the mangle as Pickering defines it.  A scientist posits a theory, and builds an instrument to test the theory (Instruments are important to Pickering's ideas of practice).  S/he runs a first test, and looks at the results.  If the results are not what was unexpected, a second test follows, or perhaps a third.  The results of each test are Pickering's "material agency:" in other words, a way to describe the unexpected obduracy of things, especially things that do not perform as expected or desired.  The push/pull between the human and the material are the two halves of the mangle. Each time through the mangle changes the performer, the performance, and the results. Also important is Pickering's concept of temporal emergence.  None of the practices, and none of the results, can be absolutely known before-hand.  Knowledge, practice, production and performance are (I think I can say this for Pickering) always historically situated, always open for re-creation.

Pickering speaks of "captures" and "frames" to describe, respectively, "the things that come out of the mangle" and "the theories that are generated as a result of the mangle and subsequently go back into the mangle."  Human agency and material agency are "constitutively intertwined" and "interactively stabilized" (17)  Scientific knowledge is sustained in extended representational chains. (70) Associations and alignments are made from the material apparatus and its performance out to the world of theory (69)  Another key concept is the "disciplined" human agency -- that is, a person who practices and thinks on the authority of theory accepted by his or her discipline.  In this way Pickering accounts for the interaction of obdurate concepts with obdurate material. So how to establish facts? Pickering says "...my suggestion is that we should see empirical scientific knowledge as constituted and brought into relation with theory via representational chains linking multiple layers of conceptual culture, terminating in the heterogeneous realm, of captures and framings of material agency, and sustaining and sustained by another heterogeneous realm, that of disciplined human practices and performances. " (111)

Chapters Two through Five give examples that illuminate different aspects of the mangle.  He traces the struggles of Donald Glaser to track particles in a bubble chamber, and to stay in small science.  In the first, after many trips through the mangle, he was successful; in the second, less so, although he never attained to the burden of a two million dollar budget, as did his colleague Luis Alvarez.  He turns to the work of Italian physicist Giacomo Morpurgo, who likewise struggled to find quarks using a variety of instruments, and based on his results, revised his theories along the way, concluding that free random quarks were not to be found (98).  To further his ideas on resistance and accommodation in instrumentation and deft practice, he also describes the very interesting and somewhat difficult recreation of James Joule's "work = heat" experiments by Heinz Otto Sibum.   I must admit that chapter four more or less left me behind.  Pickering describes three steps towards building new theories:  bridging, transcription, and filling.  Bridging throws out the first part of the "cantilever," in other words, taking an old theory and applying it to a new and untested area.  Transcription is using some of the old "moves" or "steps" to go a bit further.  "Filling" is "completing the new system in the absence of any clear guidance from the base model." (116) Through a close exegesis of a rather complex passage in the notebooks, Pickering describes Sir William Rowan Hamilton's development of the mathematical system of quaternions.  (For my part, I understood Pickering's ideas by relating them to how I have learned any new software program.) Chapter Five turns to a somewhat different example:  the workers in GE's Aero Engine Group plant at Lynn, Massachusetts who were rather reluctantly forced into a better acquaintance with numerically controlled machine tools.   In this case, Pickering argues that social roles and practice were mangled together.

Chapters Six and Seven turn again to theoretical questions and take issue with other schools of
thought.  In defining scientific practice as the work of cultural extension (3) Pickering puts himself in the way of talking to other sociologists. While informed by Bruno Latour's actor-network theory, and unwilling to enter into a realist or positivists account of knowledge, he also resists the move to semiotics, preferring instead a description that depends on practices. He likewise turns away from the Collins and Yearley debate about accounts of material agency by suggesting that although -- yes -- humans have to do the telling (so far no volunteers among the inanimate), nevertheless, no account of the discovery of knowledge can be understood without understanding that said knowledge is temporally emergent, and in effect, re-created in the telling afterwards.  Scientists or sociologists have an equal right to the telling.

Pickering rejects the actor-network to the degree that human and material agency are supposed to be symmetrical.  He says that it makes sense to talk about people planning to reach goals; it does not make sense to think of say, doorstops, as planning for goals. Although humans and materials are not symmetrical, for Pickering the world is post-humanist, in that Pickering takes issue with the SSK explanations that focus on human agency, and particularly on self-interest as motivation.   Self-interest leads (in my mind) to politics, and here Pickering seems to desire to engage without having an agenda beyond a general attraction for cyborgs (228).

One question I have on his theory:  Pickering distrusts floating constraints that are simply "out there," invoked as reasons for results, and not as "things that can go through the mangle."  Earlier, however, he says, "Constraint is synchronic, preexisting practice and enduring through it, while resistance in diachronic, constitutively indexed by time." (66)  How are constraints to be understood?  (Temporality appears to be the key to Pickering's concepts, and I would like to discuss the ideas on p 220 and following).