The Metaphysics of Science.
Alexander Bird Dartmouth College, NH, and the University of Edinburgh
Metaphysics, rather than the avoidance of it, is back at the heart of the philosophy of science. This book is a contribution to that trend. The best instances provide meaty answers to substantive problems. But the danger with metaphysics is the temptation of system building. Apart from giving the reader a headache wondering what is really meant by these abstract structures, they leave her or him perplexed as to the point of it all. This volume aims at the former but achieves only a little more than the latter. By ploughing its own furrow, it either ignores or is at cross purposes with some central concerns of the metaphysics of science.
My main argument is with Dilworth's treatment of anti-realism. Being a realist, he criticizes van Fraassen for not coming to grips with the real characteristic of realism. This he takes to be the opinion that science aims to provide explanations. Van Fraassen, he says, mischaracterizes the realist view as being that science aims to provide a literally true story of what the world is like. The boot, however, is on the other foot. By Dilworth's criterion van Fraassen is a realist since he too has a place for explanation (albeit a pragmatic notion thereof) in science. At the same time, Dilworth's distinction between description and explanation itself betrays non-realist leanings. To my mind a true realist must reject this. From a realist perspective one of the things that a full description of the world will include will be an account of what explains what. Explanatory relations, including causal ones, are facts like any other. Put the other way round, if a full description of the world were not to include explanations, then what business would science have in dealing with them? For this would imply that there are no explanatory facts and this in turn would suggest that what we call explanations are at best projected on to or constructed out of the non-explanatory facts. That would appear a thoroughly anti-realist position.
Other topics which I thought Dilworth was tackling from an oblique angle were laws and natural kinds. The superficial ground for this is a lack of discussion of the main lines of thought we have become accustomed at least to being mentioned. As regards natural kinds, Kripke gets a reference in a footnote and Putnam is not mentioned, though Dilworth takes an essentialist line not far removed from the views of those philosophers. In a book subtitled 'An Account of Modern Science in Terms of Principles, Laws and Theories', nowhere is there a clear exposition of what laws are or might be, let alone, for instance, a discussion of the relative merits of nomic necessitation versus regularity conceptions of law.
Moving to Dilworth's positive views, we find a structure which is something like this. Observation yields 'empirical laws' which are just regularities. The job of the scientist is to explain these laws, that is to show how they are manifestations of the discipline's basic principles. This is what is achieved by the theoretical model. There is not a lot by way of exemplification, but one instance might be the following. Boyle's law is an empirical law - an observed regularity. The principles of our discipline are Newton's laws of motion. Our theoretical model has a 'substantial' element - the ontological bit which tells us what sorts of stuff we are dealing with, molecules in this case. It employs the basic principles, Newton's laws, working on the substance, the molecules, and by relating magnitudes at the theoretical level with those at the observable level, e.g. mean kinetic energy and temperature, it is able to derive the empirical law. This is all very well and the same story could be extended to cover particular events like the extinction of the dinosaurs as well as empirical regularities (though Dilworth does not say so).
Newton's laws are refined principles. They are mathematically precise. They contrast with fundamental principles, of which there are, according to Dilworth, three in number. These are the principles of the Uniformity of Nature, of Substance, and of Causality. These are very general in nature. For instance, the principle of the Uniformity of Nature states that change takes place according to rules. I have a number of problems with these principles. First, they get restated in forms which do not seem to be equivalent. So, for instance, the principle of the Uniformity of Nature is also taken to say that similar states are succeeded by similar states. Even if the world and all change in it are governed by deterministic laws, the most we can be assured of is that identical states will be followed by identical states, and with indeterministic laws even that is not guaranteed. The second problem is best expressed by Dilworth himself: 'The three ontological principles . . . are extremely general, so general in fact that they are seldom if ever referred to in the doing of science.' So what do they explain then? It may be true that modern science presupposes that the world is law-governed. But this does little to characterize science, except in so far as if people believed this principle to be false they would not bother donning their lab-coats. Dilworth does go on to point out that the principles do exist in explicit, refined forms, such as spatial and temporal invariance principles, conservation laws, and the law of inertia. But in so far as we are now getting towards substantive claims which have some level of empirical support, we no longer need to bother with the inexplicit and vague principles we started with. Perhaps we can see our most general laws as the product of an interplay between experience and some very general and vague conceptions of the way things are. But I do not see the importance of this.
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|Publication:||The British Journal for the Philosophy of Science|
|Article Type:||Book Review|
|Date:||Jun 1, 1997|
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