Sunday, January 15, 2012

Paradigms, research communities, and the rationality of science


An earlier post on scientific explanation provoked some interesting comments from readers who wanted to know why Thomas Kuhn was not mentioned.  My brief answer is that Kuhn's contribution doesn't really offer a theory of scientific explanation at all, but instead an account of the cognitive and practical processes involved in formulating scientific knowledge.  Here I'll dig into this question a bit deeper.

In The Structure of Scientific Revolutions (1962) Kuhn asks us to recenter our thinking about scientific knowledge in several important ways.  He de-emphasizes questions about the logic of theory and explanation.  He argues that we should not think of science as an accumulation of formal, logical and mathematical expressions that permit codification of observable phenomena.  He doubts the availability of a general, abstract "scientific method" that serves to guide the formation of scientific knowledge.

Against the abstract ideas about the logic of science associated with positivism, Kuhn advocated for a more practical and historical study of science as a concrete human activity.  He arrives at several ideas that have turned out to have a great deal of influence -- the idea of a scientific paradigm, the idea of incommensurability across paradigms, and the idea that science doesn't just consist in the formal theories that a research tradition advances.  But the most fundamental insight that he developed throughout his career, in my judgment, is the idea that we can learn a great deal about method and scientific rationality by considering the history of science in close detail.

This approach has important implications for the philosophy of science at numerous levels.  First, it casts doubt on the hope that we might reconstruct an ideal "scientific method" that should govern all scientific research.  This was a goal of the logical positivists, and it doesn't survive close scrutiny of the ways in which the sciences have developed.  Second, it leaves room for the idea of scientific rationality, but here again, it suggests that the standards of scientific reasoning need to be specified in each research tradition and epoch, and there is no single "logic" of scientific reasoning that could be specified once and for all.  The injunction, "Subject your theories to empirical tests!", sounds like a universal prescription for scientific rationality; but in fact, the methods and processes through which theories are related to observations are widely different throughout the history of science.  (And, of course, the post-positivist philosophers of science demonstrated that we can't draw a sharp distinction between observation and theory.) Methods of experimentation and instrumentation have varied widely across time and across disciplines.  So empirical evaluation takes many different forms in different areas of the sciences.

There is an implicit tension between a sociological and historical understanding of the sciences, on the one hand, and a realist understanding of the sciences, on the other.  When we look at the formation of scientific beliefs and theories as the output of a specific research tradition and set of research institutions, we will be struck by the scope of contingency that seems to exist in the development of science.   When we look at science as a set of theories about the world, we would like to imagine that they are sometimes true and that they represent reality in approximately the way that it really works.  And we would like to suppose that the cognitive and social values that surround scientific research -- attentiveness to data, openness to criticism, willingness to revise one's beliefs -- will gradually lead to systems of scientific belief that are more and more faithful to the ways the world is.  From this perspective, the contingency and social dependency of the research process seems at odds with the hope that the results will be univocal.

Following Kuhn's historical turn, efforts to place scientific knowledge within a social context gained support within sociology rather than philosophy.  A field of thought emerged, called the sociology of scientific knowledge (SSK), which took very seriously the idea that social conditions and institutions very deeply influenced or created systems of scientific belief.  Here we can think of David Bloor (Knowledge and Social Imagery), Barry Barnes et al (Scientific Knowledge: A Sociological Analysis), and Bruno Latour (Laboratory Life: The Construction of Scientific Facts), who took the discipline in the direction of a more relativist understanding of the nature of systems of scientific belief.  According to the relativist position on scientific knowledge, belief systems are internally consistent but incomparable from one to another, and there is no absolute standard that allows us to conclude that X is more rationally justified than Y as an explanation of the world.

Here is David Bloor towards the beginning of Knowledge and Social Imagery:
The sociologist is concerned with knowledge, including scientific knowledge, purely as a natural phenomenon. The appropriate definition of knowledge will therefore be rather different from that of either the layman or the philosopher.  Instead of defining it as true belief -- or perhaps, justified true belief -- knowledge for the sociologist is whatever people take to be knowledge.  It consists of those beliefs which people confidently hold to and live by. In particular the sociologist will be concerned with beliefs which are taken for granted or institutionalised, or invested with authority by groups of people. (5)
He goes on to assert that the sociology of science needs to be -- causal, impartial with respect to truth and falsity, symmetrical in explanation, and reflexive (its principles should apply to sociology itself) (7).

From a philosopher's point of view, it would be desirable to find a position that reconciles the social groundedness of scientific belief formation -- and the self-evident ways in which the research process is sometimes pushed by non-cognitive, non-rational forces -- with the ideas of scientific truth and reference.  Essentially, I think that most philosophers would like to acknowledge that human rationality is socially constituted, but is still a form of rationality, and is capable of discovering approximate truths about the world.  It would be desirable to arrive at a philosophy of science that is both sociologically informed and realist.  Imre Lakatos took something like this perspective in the 1970s in his writings about scientific research programmes (The Methodology of Scientific Research Programmes, Criticism and the Growth of Knowledge). But in general, it is my impression that the discipline of the philosophy of science hasn't taken much heed of the challenges presented by SSK and the more sociological-historical approach. That is unfortunate, because the premises of the sociological-historical approach, and of the SSK approach in particular, are pretty compelling.