This metaphor reflects Harry Collins's thinking on the matter of scientific change and appears in his reply to Pickering's critique of 'Changing order', reproduced in the post-script of the 1992 edition - a veritable metaphor smack-down.
I don't think it is either readily apparent or obvious enough how important the role of metaphors is in the type of thinking the history and sociology of science advocate. In fact, 'science studies' run on metaphor there where it matters most - the theory of how science changes.
I intend to review here three important metaphorical postures.
1. Political revolutions/Religious war.
This is the metaphor behind Kuhn's proposal of how science changes. Kuhn says that he uses the model of political revolutions, but because he also talks of faith, conversion and hints at the idea of excommunication, I think a certain hint of religious war is also present there.
Here are a couple of key passages from Chapter 9 of the Structure of Scientific Revolutions:
Political revolutions are inaugurated by a growing sense, often restricted to a segment of the political community, that existing institutions have ceased adequately to meet the problems posed by an environment that they have in part created. In much the same way, scientific revolutions are inaugurated by a growing sense, again often restricted to a narrow subdivision of the scientific community, that an existing paradigm has ceased to function adequately in the exploration of an aspect of nature to which that paradigm itself had previously led the way. In both political and scientific development the sense of malfunction that can lead to crisis is prerequisite to revolution. Furthermore, though it admittedly strains the metaphor, that parallelism holds not only for the major paradigm changes, like those attributable to Copernicus and Lavoisier, but also for the far smaller ones associated with the assimilation of a new sort of phenomenon, like oxygen or X-rays. Scientific revolutions, as we noted at the end of Section V, need seem revolutionary only to those whose paradigms are affected by them. To outsiders they may, like the Balkan revolutions of the early twentieth century, seem normal parts of the developmental process.Here from Ch. 10:
Then, as the crisis deepens, many of these individuals commit themselves to some concrete proposal for the reconstruction of society in a new institutional framework. At that point the society is divided into competing camps or parties, one seeking to defend the old institutional constellation, the others seeking to institute some new one. And, once that polarisation has occurred, political recourse fails. Because they differ about the institutional matrix within which political change is to be achieved and evaluated, because they acknowledge no supra-institutional framework for the adjudication of revolutionary difference, the parties to a revolutionary conflict must finally resort to the techniques of mass persuasion, often including force.
Before they can hope to communicate fully, one group or the other must experience the conversion that we have been calling a paradigm shift.(...)Max Planck ... sadly remarked that ‘a new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.’(...)Conversions will occur a few at a time until, after the last hold-outs have died, the whole profession will again be practicing under a single, but now different, paradigm.
2. The ice-cream
Here is the key passage:
One might say that theories of science and of society must have the right consistency. There are theories- ethnomethodology is a good example -which seem to allow society to be too thin and gaseous, as though everything that happens is a local achievement. What these approaches do not explain is why some things are harder to change than others. Why is it harder to establish existence of, say, paranormal phenomena than, say, optical pulsars? These theories fail to explain how it is that it is easier to agree or believe some things today because certain things happened yesterday.
At the other extreme there are theories of science, such as those favored by the rationalist philosophers, where scientific life is like a preformed shape of solid stone; it cannot be changed except by violent and damaging distortion.
There is an in-between kind of theory where the community gives form
to scientific beliefs but they are unchangeable once set. The analogous consistency of concrete rather than stone- still flowing liquid that solidifies when left. But all beliefs require work to maintain them -they do not stay set by themselves. Few 'constructivists' would nowadays admit to holding concrete-type theories, though, as we will see, some of Latour's formulations have too much rigidity; objects that are 'black-boxed' are hard to un-black-box -they are not much different from stone.
Better theories give cultural life the consistency of a more or less thick liquid. A liquid never sets, can be transformed into any shape, but resists rapid transformations. One may make progress through mud, but only by slow movement, not by running. Such theories as Pickering's suggest a slowly flowing liquid whose shape at time 't' is always closely related to its shape at time 't-1'. Though liquid is a more appropriate consistency for representing science than gas, stone, or concrete, we can improve the metaphor further. There are two aspects of science still unrepresented: the continual input of energy that is needed to maintain the shape of our beliefs - they will deteriorate without maintenance-and the potential for more rapid change during periods of revolutionary or extraordinary science. Ice is a good model, for ice needs energy to keep it set, but ice cream is better still because it is a little less rigid.
Ice cream, if left to itself, will slowly lose all form. Heat or pressure representing the revolutionary or extraordinary periods of science-will turn it rapidly to liquid. In Changing Order the world of the TEA-laser is thoroughly frozen, whereas the other two studies show the speed with which local hot spots can develop. Ice cream is a good aide-memoire lest we lose sight of this aspect of science.
This metaphor is used by Lorraine Daston and Peter Galison in their most recent book (not the last one, I hope) called 'Objectivity'. The same issue of change in science is at stake. They use this model to critique the rigid idea of revolutionary change and to fill the void of incommensurability, both features of Kuhn's theory or rather features that are very often read into Kuhn's theory for reason of Kuhn's use of the 'conversion' metaphor and the comparison with Gestalt switches.
Peter Galison has critiqued the Kuhnian theory of change before by proposing the brick layer model - yet another metaphor. He argues that when science changes not everything is being swept away at once and transported into the new world: science changes asynchronously - some aspects shift rapidly to a newer phase while others lag behind. There can be for example a big shift in theory while experimentalists still use the old methods for a while.
There is certainly some of the 'brick layer' model into the avalanche metaphor. Here is the key passage from the introductory chapter of their book:
Objectivity is neither the fruit of an incremental evolution nor a sudden explosion on the scientific scene - nor an all-at-once Gestalt switch. Scattered instances of scientific objectivity in word and deed started to appear in the 1830s and 1840s, but they did not thicken into a swarm until the 1860s and 1870s. Instead of either a smooth slope or an abrupt precipice, the emergence of scientific objectivity (and other epistemic virtues) might be imagined on the analogy of an avalanche: at first, a few tumbling rocks, falling branches, and minor snow slides amount to nothing much, but then, when conditions are ripe, individual events, even small ones, can trigger a massive, downward rush.A couple of conclusory thoughts:
Of course, a great deal hinges on just how to specify "when conditions are ripe." In the case of the avalanche, there will often be complicated combinations of slope, terrain, saturation, and snow-layer binding that set up the instability. The historical sequence of epistemic virtues also supplies something close to preconditions of instability. Even if conditions are known to be extremely dangerous, no one could say precisely when -or how- an avalanche might start. Like the formation of an avalanche, the potential for a previous epistemic virtue to be transvalued into an epistemic vice is localized in time, but not with on-the-dot punctuality. Just as in the case of the avalanche, preconditions must coincide with contingent circumstances. We can identify a rapidly proliferating and mutually conflicting set of ideals, each claiming to be the right way to depict the splash of a drop or the structure of a blood cell. We cannot say exactly when or why in a given domain scientists will begin to insist upon an "objective view." Rather than razor-sharp boundaries between periods, we should therefore expect first a sprinkling of interventions, which then briskly intensify into a movement, as fears are articulated and alternatives realized - the unleashing of an avalanche.
But the ambitious historian may persist: Isn't this problem, aren't all problems of historical timing, just due to insufficient information? If some Laplacean demon would turn its infinite industry and intelligence to a complete specification of all the circumstances at a given time and place, wouldn't it be possible to explain the emergence of objectivity - or, for that matter, the outbreak of the French Revolution, the invention of the magnetic compass, the rise of chivalry, yes, even the onset of an avalanche - with pinpoint precision? This is a persistent and revealing historical fantasy. It is fantastical to imagine that we can deterministically identify not only the "trigger" in historical processes - but also the detailed route of development. It is impossible not only because it is practically beyond our grasp, but also because it is incoherent. Just as in the case of the utterly useless Borgesian map that reproduces an empire in one-to-one facsimile, the Borgesian archive of all historical information would duplicate history, not explain it. Forget the thousands of microtriggers. Our interest here is, on the one hand, to capture the conditions of epistemic instability, and, on the other, to identify the new patterns that result - the most striking of which was objectivity.
- The three metaphors are central to three (the three?) consecutive periods in 'science studies' thinking.
- the last two are compatible with each other. They can be seen as an answer to the Kuhnian metaphor of revolutions which emphasizes systematic, holistic and instantaneous change - avalanches of ice-cream?
- the metaphors can be ordered in the following way according the idea of the radicality of change: 1. revolutions, 2. avalanches 3. ice cream.
- When it comes to the origin of the metaphor we obtain the following disciplinary picture: revolutions - history/ political science; ice-cream - classical physics(fluid dynamics); avalanches - geography.
- It's interesting that the last two metaphors are informed by the hard sciences.
- I think these metaphors are very useful pedagogically and could be used in a charismatic way in an introduction to the history and sociology of science.