What is
scientific realism?
An important strand in the story
of the philosophy of science in the past three decades has been a struggle
between realists and anti-realists. The debate turns around the most adequate
way of interpreting scientific theories that refer to unobservable entities,
processes, and properties. Realists maintain that the entities postulated by
scientific theories (electrons, genes, quasars) are real entities in the world,
with approximately the properties attributed to them by the best available
scientific theories. Instrumentalists, on the other hand, maintain that
theories are no more than instruments of calculation, permitting the scientist
to infer from one set of observable circumstances to another set of observable
circumstances at some later point in time. (Important recent contributions to
the theory of scientific realism include (Miller 1987), (Leplin 1984), (Putnam
1984), (Putnam 1982), and (Boyd 1984), (Van Fraassen, Churchland, and Hooker
1985), and (Gasper 1990).)
It is worth noting at the outset
that scientific realism emerges from a tradition of thought in empiricist
philosophy of science; but that it provides the basis for a cogent critique of
many early positivist assumptions. In particular, scientific realists have
rejected (obviously) the instrumentalism associated with logical positivism;
the assumption that all scientific knowledge takes the form of empirical
regularities; the assumption that the ultimate goal of scientific research is
the formulation of lawlike generalizations; and, to some extent, the assumption
that the hypothetico-deductive model is the unavoidable foundation of empirical
reasoning in the sciences. Scientific realism is therefore a sympathetic basis
in the philosophy of social science for those philosophers and sociologists who
are most concerned to put aside the positivist origins of both philosophy of
science and sociology. Mario Bunge argues strongly that scientific realism is
most suited to an appropriate methodology for the social sciences; (Bunge
1993).
The issue of scientific realism
has been one of the central hinges of debate within the philosophy of science
for the past thirty years. The central issue is this: Do scientific theories
and hypotheses refer to real but unobservable entities, forces, and relations?
Or should we interpret theories and hypotheses as convenient systems through
which to summarize the empirical regularities of observable entities and
processes, with the apparent reference to unobservables as simply a “fa¨on de parler” with no greater significance
than the imagined can opener in the classic joke about the economist and the
accountant? Scientific realism maintains that we can reasonably construe
scientific theories as providing knowledge about unobservable entities, forces,
and processes, and that understanding the progress of science requires that we
do so. Instrumentalism denies that it is reasonable to interpret hypotheses as
referring to real unobservable entities; instead, a scientific theory should be
understood as an instrument of calculation, permitting the scientist to make
predictions about one set of observable variables on the basis of knowledge of
the current state of another set of observable variables. We may take Jarrett
Leplin’s formulation (Leplin 1984, pp. 1-2) as a representative statement of
scientific realism:
Debates about scientific realism
most commonly derive their scientific examples from the natural sciences. The
entities in question are such things as quarks, genes, quasars, and
superfluids. But social theories
too involve concepts that appear to refer to unobservable entities: classes,
systems of norms, and scissors crises, for example. So the issue of realism
arises in the social sciences as well. If we have an empirically well-confirmed
theory that invokes the concept of an X (a hypothetical social entity or
force), is this a reason to believe that X’s exist? Or is there some reason to
suppose that the ontological assumptions of scientific realism are justified in
the natural sciences but not in the social sciences?
Boyd,
Richard N. 1984. The Current Status of Scientific Realism. In Scientific
Realism, edited by J. Leplin.
Bunge,
Mario. 1993. Realism and Antirealism in Social Science. Theory and Decision 35 (3):207-235.
Gasper,
Philip. 1990. Explanation and Scientific Realism. In Explanation and its
Limits, edited by D. Knowles. Cambridge:
Cambridge University Press.
Leplin,
Jarrett. 1984. Scientific realism.
Berkeley: University of California Press.
Miller,
Richard W. 1987. Fact and method : explanation, confirmation and reality in
the natural and the social sciences.
Princeton, N.J.: Princeton University Press.
Putnam,
Hilary. 1982. Three Kinds of Scientific Realism . The Philosophical
Quarterly 32 (128).
———. 1984. What is
Realism? : in Leplin, ed. (1984).
Van
Fraassen, Bas C., Paul M. Churchland, and C. A. Hooker. 1985. Images of
science : essays on realism and empiricism, with a reply from Bas C. van Fraassen, Science and its conceptual foundations. Chicago: University of Chicago Press.