Ruminations on fecundity
Tue 12 Jun 2007 01:39 AM
Philosophers of science who argue over the virtues of theories typically concentrate on fit with observation, novel prediction, support for intervention, explanation, and unification. For each, there are arguments that it is truth-indicative, that it is not, that it marks a theory worth accepting, that it does not, and so on. Philosophers have had less to say about fecundity, the virtue a theory has when it gives us some sense of what to do next in enquiry. Obviously, scientists can make no use whatsoever of a theory that gives them no sense of what they might do next. The remainder of this post provides some almost connected ruminations on the subject.
Lakatos' Methodology of Scientific Research Programmes is a notable exception to philosophers' neglect of fecundity. (I have the affectation of using Lakatos' British spelling of "programme" to distinguish research programmes in a Lakatosian sense from more quotidian programs.)
Consider, as an example, research into the influence of hormones on development; what Helen Longino dubs the linear-hormonal model (LH). The programme "can continue to generate studies that are used to support microhypotheses about the etiology of particular forms of behavior that are consistent with [its] broader model." (For references, see Hormone Research as an Exemplar of Underdetermination.) Study after study can observe a correlation between prenatal hormone levels and gender-linked juvenile behavior. Different populations and data sets may be used, and so in some sense the programme suggests further research. Yet the programme dwells on observations of superficial phenomena, accumulating similar results insufficient to underwrite practitioners' claims about brain development. The programme's further direction doesn't seem to get anywhere.
In Lakatos' jargon, a research programme is theoretically degenerating if it does not yield any new testable predictions and empirically degenerating if its predictions turn out to be false.
One might defend the LH programme: Its research does make predictions and those predictions are often true, so it is both theoretically and empirically progressive (i.e., not degenerating.)
However, the LH programme only makes the conservative prediction that an observed correlation between two variables will continue in further instances. The predictions of a progressive research programme should be novel and unexpected, so LH is either somewhat degenerating or only minimally progressive (depending on how you want to spin it.) Unfortunately, surprisingness is most naturally treated as a psychological notion. This would lead us to say that jumpy, unimaginative scientists (who are surprised by banal predictions) will be judged to enjoy more progress than imperturbable scientists (who are surprised by nothing.)
The LH programme offers a kind of pathological fecundity, but are there any scientific research programmes that lack even that sliver of the virtue?
A clear example, I think, is so-called Intelligent Design theory. It is deliberately constructed so as to be incompatible with the research programme of evolutionary biology but to stop short of actually describing the alleged designer. It makes some predictions, perhaps, but not ones that can guide any sort of research programme.
A search of the blog reminds me that I have discussed these issues before, a propos of demarcation and pragmatism. As a slight tangent, I think this is an advantage of having a blog: If I had merely thought those things, I would have forgotten irretrievably. If I had written notes to myself on scraps of paper, they would either be buried in a file cabinet or thrown away long ago. Moreover (as I pointed out in the last post) notes to myself would have been more elliptical than the blog post. Even if I had exhumed them, it might have required some effort even for me to reconstruct what I had meant.
I am not certain how to draw these strands together, but during last Summer's reading group I discovered this relevant passage in Dewey's Logic:
The history of science, as an exemplification of the method of inquiry, shows that the verifiability (as positivism understands it) of hypotheses is not nearly as important as is their directive power. As a broad statement, no important scientific hypothesis has ever been verified in the form in which it was originally presented nor without very considerable revisions and modifications. The justification of such hypotheses has lain in their power to direct new orders of experimental observation and to open up new problems and fields of subject matter. In doing these things, they have not only provided new facts but have often radically altered what were previously taken to be facts. [p. 519]To my knowledge, Dewey's point here was not directly influential on later philosophers and historians who said similar things. Thomas Kuhn (who listed fecundity among the scientific values) and Martin Rudwick (who has often emphasized the fact that a victorious theory typically arises from attempts to develop earlier theories) probably had not read this passage in Dewey. (This is a safe bet, because almost no one read Dewey's Logic.)
As a final note, I should say that the word 'fecundity' has a strange resonance for me. My homepage and e-mail are hosted at fecundity.com, a domain I have owned since 1999. I bought hosting and my own domain just so that I could toy with writing CGIs, an activity forbidden on the university servers. I had first encountered the word 'fecundity' years before when reading Jeremy Bentham. This gave it a strange association with the internet, since the live webcam of Jeremy Bentham's mummified body was one of the cool things on the net back then. The word has a nice sound to it, and the connection motivated one of the first banner ads I made for the site: