Thursday, September 30, 2010

Hacking and Franklin on the Functional Complexity of Evidence

After posting my paper here, in the last few days, I've just happened to come across two fabulous statements related to my position. Of course, just when you start to think you're doing something a little bit original, you come across all kinds of people saying basically the same thing.

Ian Hacking, on the first page of the monumental "Experimentation and Scientific Realism":
Experiments, the philosophers say, are of value only when they test theory. . . So we lack even a terminology to describe the many varied roles of experiment.  (Hacking 1982, p. 71)
And Allan Franklin, on the first page of his Selectivity and Discord:
Experiment plays many roles in science.  One of its important roles is to test theories and provide the basis for scientific knowledge.  It can also call for a new theory. . . Experiment can provide hints about the structure or mathematical form of a theory, and it can provide evidence for the existence of the entities involved in our theory. . . it may also have a life of its own, independent of theory: Scientists may investigate a phenomenon just because it looks interesting. Such experiments may provide evidence for future theories to explain. (Franklin 2002, p. 1)
It is a nice surprise to find myself in such good company.  The aim of my paper, of course, is to try to provide a coherent picture of and some terminology for the various roles of evidence.  One of the points that I make in the paper, which I'm not sure Hacking or Franklin would accept, is that there is a useful (functional) distinction to be drawn between observational and experimental evidence.  I suspect they might even say that I leave some roles out of my picture.


  1. I have long thought of empirical investigation as a continuum between passive (naive) observation and active (interventionist) observation. It seems to me that we have been so obsessed by theory-dependence that we overlook the relativity of theory to domains of investigation, and so we may investigate a domain without theory in both modes or some mixture of them.

  2. Besides Allan Franklin, George Smith, bill harper, and Michel Jansen have also been exploring these themes in their work (often in hps mode, so in works on newton and Einstein).

  3. Are we talking here about evidence or experiments?

    My gut reaction is to say that experiments have many functions, one of which is to provide evidence for or against hypotheses.

    It sounds as though you want to say instead that, while all experiments are sources of evidence, the evidence they provide has many functions.

    I don't know why exactly I prefer the first version - I just think it stays closer to the intuitive notion of "evidence" as something that is adduced in support of an assertion or belief.

  4. J.S. Mill has a lovely discussion of observation vs. experimental evidence in Chap. VII Of Observation and Experiment in his System of Logic. Of course, you are arguing for more complexity than he presents there, but it might be a nice historical touchpoint for you.

  5. Eric and Heather - Thanks for the pointers!

    Jonathan - I see why you might go that way. Part of my argument, which will come to the fore in my 2nd paper on the subject, is that the "intuitive" notion is the source of many problems. Another part that I try to make clear in the paper I posted the other day is that it also doesn't really capture the uses of evidence in scientific practice.

  6. Now I know how to go at this! I of course agree with Jonathan's intuitions, and I look forward to seeing your account of the trouble they cause. But you are so far making an empirical argument, right? Our concept of evidence, you are saying, "doesn't really capture the uses of evidence in scientific practice". Well, what's your evidence for that? That is, how do you study the "uses of evidence in scientific practice". In this case, your source is Goldstein and Goldstein, which, as you say, draws on Snow's own account, and which you grant is inadequate as evidence (at least in the narrow sense).

    You say, you are only illustrating the idea here. But where does your knowledge of practice come from? And how does it relate to the studies of "laboratory life" that have been and continue to be produced in STS?

    I get worried when my intuitions are challenged by empirical arguments, mainly because I know that "studies show" all kinds of contradictory things. It would surprise me if a comprehensive "philosophy" of evidence could capture all its "uses in practice". (Just a philosophy of hammers won't anticipate all the ways carpenters use them.)

    In fact, I'd much prefer to look at how evidence functions "in theory", i.e., in the written reporting of results and the drawing of implications for general laws. That's really where philosophy of science can show its merit. In relation to practice, we're going to get beaten to a pulp by ethnographers.