ABNER SHIMONY

COMMENT ON SAGAL

Sagal criticizes naturalistic epistemology generically for falling short of the mission of justifying the sciences with "no circles and no gaps," and he outlines a program, essentially along the lines of Paul Lorenzen's constructive philosophy, which is intended to carry out that mission. I shall present some reasons for believing that the constructive program is unachievable. The answer which I shall then offer to Sagal's criticisms of naturalistic epistemology is based in large part upon the inevitability of curtailing our philosophical ambitions.

The part of constructive philosophy which Sagal presents in greatest detail, as a demonstration piece for its power, is philosophy of mathe­matics. He has correctly assessed the area of his greatest strength. It is indeed astonishing how much of mathematics, including most of the analysis which is used in the natural sciences, can be recovered constructively. Even a philosopher who is unwilling to reject on principle all of non-constructive mathematics can be impressed by the achievement of the constructivists and can admit that they have made a strong case that a large part of mathematics is an artifact of the mind.

But what reason is there for thinking that constructivism can be extrapolated beyond the domains which can plausibly be regarded as man-made (which include language, logic, perhaps mathematics, per­haps ethics, and not much else)? To be sure, Kant suggested a way in which the domain "of the natural sciences might be understood as man-made - by regarding nature as experience subjected to law, and considering the laws in their general form to be imposed by the mind. If, however, one does not regard the mind as a transcendental legis­lator, but rather as an entity in nature - and Sagalappears to be a naturalist to this extent - then one cannot use the argument strategy for extending constructive analysis to the natural sciences.

There exists, however, a non-Kantian defense of constructivism in the natural sciences, presented by Hugo Dingler, Lorenzen, and other protophysicists: they insist that scientific theory is founded upon practice, and of course crafts and technologies are human accomplish­ments. Since Sagal does not recapitulate their arguments in any detail,

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Abner Shimony and Debra Nails (eds.), Naturalistic Epistemology, 333-336. © 1987 by D. Reidel Publishing Company.

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and since my knowledge of the literature is limited, I cannot pretend to offer a decisive criticism, but I can state my reasons for skepticism.

(1) It is hard to see how any extrapolation of principles from practical situations in which they have been successfully applied to new situations can dispense with a procedure of induction, and therefore the extrapolation is no more justified without circles and gaps than are the procedures of inductive logic. In reply, some constructivists resort to a vindicatory argument, which Reichenbach and others outside their school have invoked to defend induction: we cannot be sure that the principles of protophysics will work, but we cannot dispense with them and therefore it is reasonable to commit oneself to them (Peter Janich, cited by Andreas KamIah, 1981, pp. 220-1). But a gap in the argu­ment remains, because one does not know that an alternative proto­physics, as yet unformulated, will not work as well as the Euclidean­Galilean one to which the constructivists are committed. KamIah says:

Angenommen nun, aile bisherigen Normensysteme der Liingenmessung, welche nicht die euklidische Geometrie voraussetzen - fUr andere Bereich der Protophysik gilt Analoges - seien tatsiichlich als zirkelhaJt erwiesen, was wiire die Situation? Kann man eine Aussage also apriori gilltig ansehen, deren Aprioritiit nur induktiv erwiesen werden kann, so dass sozusagen ihre Aprioritiit'aposteriori' giiltig ist. (Kamlah, 1981, p. 223)

(2) By now we have seen many concrete examples of theories which are accurate in their predictions in a restricted domain but inaccurate beyond it. They are limiting or special cases of theories which are reliable in broader domains. Niels Bohr introduced the notion of a correspondence principle governing the relation between quantum physics and its classical limiting cases. An extension of his notion can be applied whenever a theory is honorably superseded by a more accurate and/or more general one. Is it inconceivable that the principles of a practically efficacious protophysics are the 'correspondence limits' of some more general principles? This suggestion is particularly attractive if one takes a naturalistic view of human beings and recognizes that human practical activity is limited in spatial extent, in temporal duration, in the range of the objects handled, and in the fineness of human sensory observation. Is it inconceivable that instru­ments constructed in a shop, in accordance with Euclidean and Galilean principles, will be capable of discriminations which lend evidential support to modifications of those principles? If one studies in detail the machine shop procedures for fabricating an interferometer, and sees why it can be used to make length measurements more

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precisely than the micrometers which were employed in constructing it, then the program just now suggested becomes quite plausible.

(3) The special theory of relativity provides an exemplary instance of inferring a scientific theory which corrects the principles assumed in the machine shop. The extraordinary agreement between the crucial predictions of this theory and observation, its internal coherence, and its ability to account for its own genesis constitute very strong evidence against the constructive philosophy of the natural sciences. A good part of the constructivist literature is devoted to disputing the virtues which I have just attributed to the special theory of relativity - to exhibiting its alleged conceptual incoherence and to showing that all its successful experimental predictions could be achieved within a Euclidean-Galilean framework. This dispute is too complicated and technical to summarize here. I shall only point out that there is an excellent anthology by Joachim Pfarr (1981) which reprints some of the relevant critiques of relativity theory by the protophysicists along with some assessments of their arguments. A later paper by John Stachel (1983) is also relevant. My impression is that the critics of the protophysical variety of constructivism make overwhelmingly a better case than the defenders.

Sagal's assertion that naturalistic epistemology has fallen short of the mission of justifying the sciences in based almost entirely upon an analysis of a paper of Quine. I agree with much of what SagaJ says about Quine, as can be seen from my "Integral Epistemology" in this volume and from my comments on the paper of Levine, but I do not see how his criticisms are decisive against the generic enterprise of naturalistic epistemology. In particular, if one does not simply identify epistemology with psychology, but requires that a part of its method is a dialectic whereby it criticizes its own starting point, then one is conforming to Sagal's maxim "that philosophy must be self-critical." (I suggest, incidentally, that Quine is more dialectical in practice than either Sagal or he himself admits.)

A very important part of the task of self-criticism is to examine the concept of justification itself. The concept of justification which one entertains at the beginning of a philosophical investigation may turn out to be too narrow, too idealized, and too much borrowed from a favored discipline. When Sagal says that the task of philosophy "is to provide the foundation for all other intellectual disciplines" and when he speaks of construction with "no circles and no gaps," he conveys the impres­sion that his concept of justification is borrowed from mathematics, much as Descartes' was in his Discourse on Method. But may not

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the standards of justification in mathematics be inappropriate or inachievable in the natural sciences, the social sciences, and in practical activities? There are several different ways to approach this question. One is an examination of the history of thought, to see how dedicated searchers for knowledge were forced to discriminate between mathe­matical and causal necessity, and to retreat from imposing the ideal of mathematical demonstration in other disciplines. Another way is to reflect upon the place of human beings in nature and upon the constitu­tion of the human faculties, a reflection which will almost inevitably force us to recognize human limitations and fallibility. A third way is to engage in dialogue, and since Sagal is a follower of Lorenzen, who espouses a dialogical method, I suppose that this is the way he would prefer.

Since the version of naturalism which I propose in 'Integral Epis­temology' has a dialectical component, there should not be an impasse between Sagal and me. I have found counterparts in the writings of the constructivists to all the four theses for organizing dialectic that were listed in my paper, including notably the recourse to vindicatory arguments. (This last point should contribute greatly to a consensus between us, since it constitutes a definite retrenchment from the ideal of mathematical justification.) The constructivists' emphasis upon initiating theoretical investigation in the realm of practice is cognate to my thesis that "commonsense judgments about ordinary matters of fact have a prima facie credibility, which should not be discounted without clear positive reasons". Where I sharply diverge from the construc­tivists, however, is in my conviction that clear positive reasons for discounting initial commonsense and practical judgments have some­times been found. In my opinion, the dialectical method gains in strength rather than loses because of its flexibility.

Boston University

REFERENCES

Kamlah, Andreas: 1981. 'Zur Diskussion urn die Protophysik.' In Pfarr (1981). Pfarr, Joachim: 1981. Protophysik und Relativitiitstheorie. Mannheim, Vienna, Zurich:

B. I. Wissenschaftsverlag. Stachel, John: 1983. 'Special Relativity from Measuring Rods.' In R. S. Cohen and L.

Laudan (eds.), Physics, Philosophy, and Psychoanalysis: Essays in Honor of Adolf Griinbaum. Dordrecht, Boston, and London: D. Reidel.