I argue that the reality of the weak neutral current was the upshot of particle physicists' practices, and not the reverse. [….]

[In particular]…the acceptability of the weak neutral current (and hence of the associated interpretative practices [that supported this acceptability]) was determined by the opportunities its existence offered for future experimental and theoretical practice in particle physics. Quite simply, particle physicists accepted the existence of the neutral current because they could see how to ply their trade more profitably in a world in which the neutral current was real. (136)

a) "…scientific experiment should not be equated with the passive and unproblematic observation of natural phenomena. Phenomena are grounded in experimental practices which appear unproblematic only as long as they are left unexamined. Crucial to the discovery of the weak neutral current - and crucial to the repair of the disjuncture between the experimental and theoretical practical physics communities - was a shift in the interpretative practice of neutrino experimenters. The interpretative practice of the 1960s, which supported the non-existence of the neutral current, was displaced by that of the 1970s, which made the neutral current manifest. I have tried to show that neither the practice of the 1960s nor that of the 1970s was in itself compelling of assent - each was open to counterargument. And I have therefore suggested that experimental practices and natural phenomena are inextricably bound together; assessment of one is ultimately an assessment of the other." (150)

b) "Following on from this, I have tried to show that the assessment of natural phenomena is itself conditioned by the dynamical aspect of scientific practice: that is, by the continuing process of choice of experimenters to perform one experiment rather than another and of theorists to elaborate one theory rather than another." (150)

c) the disruption of the two relatively stable periods of symbiosis between theorists and experimenters came in this instance from "'internal' dynamics of theoretical practice….particle theorists saw in t'Hooft's 1971 demonstration of the renormalisability of gauge theory opportunities for constructive practice: all of the techniques which had been developed for handling renormalisable theories could be transplanted to this area, and indeed this is just what theorists with the appropriate expertise did. Significantly, in the present context, they did this with one eye on the possibility of symbiosis with their experimental colleagues, elaborating primarily those gauge theories which were physically realistic - the Weinberg-Salam model and variants of it. In the course of this theoretical work it became apparent that some new phenomenon was needed and as we have seen, neutrino experimenters modified their interpretative practices, produced the neutral current, and reestablished the symbiosis on a new footing." (151)

d) As a result, "…the explanatory emphasis [concerning the discovery of the weak neutral current] has been on what scientists do rather than upon the phenomena which they report. I have focussed upon two aspects of scientific practice: the interpretative aspect of experimental practice, whereby happenings in the laboratory are transformed into reports about the natural world; and the dynamical aspect of both experimental and theoretical practice, relating to scientists' choices of which experiments to perform, which theories to elaborate and so on. My argument has been that, far from being distinct, these two aspects are bound up together at the level of natural phenomena. The relative acceptability of different experimental interpretative practices was conditioned by the expertise and objectives and experimenters and theorists." (151)

"Seen in this way, science no longer seems adequately described in terms of an adversarial relationship in which experiment tests theory. An image of experimenters and theorists in the production, rather than the discovery, of a congenial phenomenal world seems more appropriate." (151)

A central element of Pickering's account concerns the effort between 1972 and 1973 among members of the so-called "Gargamelle" team to persuade themselves that a "neutron background…could not account for all of the neutral current events on the film [of particle decay as recorded in the bubble chamber]" and thus, that these events were caused by the weak neutral current. "My aim will be to demonstrate the fragility - the lack of compelling force - of their interpretative practice, both as a matter of principle and as a matter of historical fact. I will then highly this fragility by contrasting the interpretative practice of the Gargamelle experimenters with that of earlier neutrino experimenters at CERN." (140)

To estimate the neutron background in the Gargamelle experiment required "Monte Carlo" computer simulations, described on 140. Examining the details of these simulations, Pickering argues, opens up several possibilities of counter-argument - derived generally from the scale of the simulation attempted (see 140) . There are four specific possible counter-arguments:

While such assumptions are by no means improper or unusual for experimenters to undertake - these are assumptions which can be reasonably questioned. As well,

Taken together, Pickering argues that these factors mean that

…it seems clear that the decision of the group as a whole to publish the claim at that time [July 1973] was influenced as much by priority concerns and the forthcoming conference season as by the conviction that the analysis was watertight.

[The implication here, further, is that since American researchers at the National Accelerator Laboratory - now Fermilab - were about to announce findings for netural currents, the Gargamelle team were pushed into publishing less than watertight evidence in order to beat the American team. (141)]

[By winter of 1973] …the NAL [American] experimenters had made changes to their apparatus and had concluded that neutral currents did not in fact exist. This result was transmitted to CERN, where the Gargamelle experimenters came under great pressure, from both the physicists and management of CERN, to either improve their result or retract it. Their position was not strengthened when CERN phsicist Jack Steinberger - a veteran of the first neutrino expriment at Brookhaven, though not a member of the Gargamelle team - made public his own Monte Carlo simulations, which indicated that a substantial fraction of the / Gargarmelle neutral-current events could be interpreted as neutron background.

The debate over the Gargamelle team's interpretative practices was finally more-or-less closed in the spring of 1974, but again it is significant to note that this cannot be ascribed to any new compelling quality of their neturon background calculations. The turning point came when the American experimenters revised their own Monte Carlo simulations and, for the second time, decided that they had indeed found evidence for neutral currents. (141f.)

…that as a matter of principle and as a matter of historical fact the interpretative practices of the Gargamelle group were not beyond legitimate doubt. Put simply, in 1973 and early 1974 particle physicists both inside and outside the Gargamelle group did not treat the neutron-background calculations as compelling assent. Assent to the practices implied assent to the existence of the weak netural current, but any physicist dissenting from the latter could quite legitimately question the former. Interpretative practice and natural phenomenon stood or fell together. (142)

It was precisely the practice of gauge theorists like Gell-Mann which guaranteed that neutral currents would be seen as a significant topic for neutrino experimenters to explore. And conversely, it was precisely the experimental reports on the neutral current which fed and legitimated the continuing practice of gauge theorists. As a real phenomenon, the weak neutral current was a bonanza for theorists and experimenters alike and the acceptance of novel intepretative practices [e.g., the Monte Carlo methods, etc.] was a small price to pay. (150)

The organization of science operates as a system of institutionalized vigilance, involving competitive co-operation. It affords both commitment and reward for finding where others have erred or have stopped before tracking down the implications of their results or have passed over in their work what is there to be seen by the fresh eye of another. In such a system scientists are always ready to pick apart and appraise each new claim of knowledge. This unending exchange of critical judgment, of praise and punishment, is developed in science to a degree that makes the monitoring of children's behavior by their parents seem little more than child's play.

-- Robert Merton