E. Contingent Realism and InstrumentalismThere are many versions of scientific realism but Wilfrid Sellars put forth a position that appears to have the status of a received view. He defines scientific realisms thus:
to have a good reason for holding a theory is ipso facto to have good reasons for holding that the entities postulated by the theory exist.{75}McMullin, a long defender of scientific realism, in a recent article defending realism says "realism had to do with the existence implications of successful theories".{76} But McMullin in a very fair discussion of both realism and antirealism qualifies his position very carefully when confronted with the evidence from the history of science which some view as the garbage heap of rejected theories.{77} He says:
The value of this sort of reminder, however, is that it warns the realist that the ontological claim he makes is at best tentative, for surprising reversals have happened in the history of science. But the nonreversible (a long list is easy to construct here also) still require some form of (philosophic) explanation, or so I shall argue.{78}Michael R. Gardner{79} provides an interesting case study of the arguments for taking the Copernican theory at first instrumentally and then realistically. Initially, many scientists and non-scientists took the Copernican heliocentric theory instrumentally as a calculating device because there were too many problems with taking it realistically. Heliocentrism was inconsistent with current Aristotelian physics, the Scriptures and the world view of the man in the street. With the development of Galilean and Newtonian physics and new observational data that became available as a result of the invention of the telescope the arguments for taking the heliocentric theory realistically became much more convincing. As this case illustrates scientists have adopted both attitudes but at different times and concerning different theories or theoretical entities. The task of philosophers and historians of philosophy is to exhibit the arguments for taking a theory realistically or instrumentally as they unfold in development of a paradigm-theory. Then there is the question whether these arguments are cogent or not. This question is extremely complex but, there is no doubt in my mind that it needs to be answered and furthermore that an answer should be attempted and that philosophers should get centrally involved in these attempts. There is a grain of truth in Fine's NOA position but it is hidden deep in NOA a kind of no philosophy philosophy. Fine says that NOA's attitude as to what is real is exactly the attitude that scientists take to this question. He calls this attitude to the truths of science the "core position". Fine says:
. . . both (the realist and instrumentalist) accept the certified results of science as on a par with more homely and familiarly supported claims. What distinguishes realists from antire~;ists, then, is what they add onto this core position.{80}I want to put the matter differently. 1 want to say that already in the core position scientists at times take on some version of the realist or instrumentalist position. For example Geoffrev Chew, a proponent of the S-matrix theory, explicitly adopts a non-realist position concerning his theory claiming that it has no "implication of physical meaning." His position sidesteps questions concerning the existence of subatomic particles.{81}
For the rival position of quantum field theory to answer the question as to whether there are electrons or quarks or tachyons scientists have to look at the merits of the evidence on a case bv case basis. There are periods in the history of any specialty when this or that theoretically postulated entity had not yet achieved conclusive observational confirmation, whatever that means in the specialty in question at a particular time. But philosophical consideration can and will be interjected to help resolve questions of the existence of this or that phenomenon when the observational evidence allows for multiple interpretations. Loren Graham puts this point very well. He says:
All Scientists in the course of their investigations must proceed beyond physical facts and mathematical methods; such theorization is one of the basis of scientific explanation. Choices among alternative courses that are equally justifiable on the basis of the mathematical formalism and the physical facts must be made. The choice will often be based on philosophical considerations and will often have philosophical implications. Thus, Fock in his interpretation of quantum mechanics defined "complementarity" as a complementarity between classical descriptions of microparticles and causality" (see p. 339). In his subsequent choice between retaining either a classical description or causality, he chose causality, and thereby lost the possibility of a classical description. He could have gone the other way. Whis decision inevitably involved philosophy.{82}One of the main problems with many versions of scientific realism or instrumentalist is that they are global positions attempting to argue that science is one or the other, whereas questions of existence or reality should be addressed on a case by case basis. Questlons of the reality of this or that phenomenon is a contingent matter. Thus, according to my position of "contingent scientific realism" acceptance of a scientific theory does not yet guarantee the existence of all the entities postulated by the theory. However, it should be said that it does provide motivation for the pursuit of research aimed at the discovery of entities postulated by such theories. Mendeleef' table of elements provided grounds for the pursuit of research connected with the discovery of radium by Madame Currie. More recently Dirac's theory of maqnetic monopoles provided grounds for experiments aimed at detecting these hypothetical particles. To theoretical papers on faster-than-light quanta by Bilaniuk{83}, Deshpande, and Sudarsham gave rise to the search for tachyons. None have been observed as yet. These and other examples can be produced which undermine the global formulations of scientific realism but which support contingent scientific realism.
Table of Contents -- Bibliography
Notes {75} Wilfrid Sellars, Science, Perception and Reality (New York: Humanities Press, 1962): p. 97. [Back]
{76} Ernan McMullin "A Case for Scientific Realism" in Scientific Realism, ed. Jarrett Leplin (Berkeley: University of California Press, 1984): p. 13. [Back]
{77} For such a list see in particular L. Lauden "A Confutation of Convergent Realism" in Scientific Realism, ed. Leplin. [Back]
{78} McMullin "Case for Scientific Realism" p. 18 [Back]
{79} Michael R. Gardner "Realism and Instrumentalism in Pre-Newtonian Astronomy" in Testing Scientific Theories, ed. John Eanrman (Minneapolis: University of Minnesota, 1983). [Back]
{80} Fine, The Shaky Game, p. 128. [Back]
{81} See McMullin for further discussion of S-matrix theory, p. 15. [Back]
{82} Loren Graham, Science, Philosophy, and Human Behavior in the Soviet Union (New York: Columbia University Press, 1987): p. 352. [Back]
{83} For the original paper which proposed the existents of such superluminal particles originally called "metaparticles" see O. M. P. Bilaniuk, V. K. Deshpande, E. C. G.Sudarshan, "Metarelativity" American Journal of Physics Vol. 30, pp. 718-723. For a discussion of tachyons and other missing particles see also Olexa M. Bilaniuk and John R. Boccio "Les particules introuvables" in La Recherche December 1973, pp. 1037-1047. [Back]
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