Intertheoretic relations

So what good, then, what special value, does chemistry offer contemporary philosophy of science Typically philosophical problems, even problems in philosophy of science, are not confined to a particular science. For general problems—problems about representation, inference, discovery, explanation, realism, intertheoretic and interdisciplinary relations, and so on—what is needed are scientific illustrations that go to the heart of the matter without requiring specialized technical knowledge of the reader. The science needed for most philosophy is familiar, not esoteric, right in the middle of things, mature and diverse enough to illustrate a variety of fundamental issues. Almost uniquely, chemistry fits the description. 

A related but distinct notion of reduction is as a dateable achievement of intertheoretic explanation. For this usage, see for instance Scerri 1994. 

When we explore the relationships theories have to one another, when one of the theories works at a more and rhe other at a less foundational level, we discover a rich and complicared srory. Consider, for example, rhe puzzling relation between physical (wave) optics and geometrical oprics. Curious aspects of the intertheoretical relation here are duplicated when one looks at the relation between quantum mechanics with its wave-like aspects and classical mechanics. 

When intertheoretic relationships are studied in flesh-and-blood science, one can see the different kinds of resources needed to establish the links. In fact, the relations between theories are usually much more subtle and varied than what the traditional perspective supposes they involve limits, coarse-graining, approximations and other mathematical techniques far more complex than the simple logical links involved in reduction. Moreover, they are not mere tools to which we turn in response to our perceptual or technological limitations. 

How should we understand the intertheoretic relations between chemistry and physics, especially quantum mechanics How might this understanding impact on general accounts of theory reduction How might it impact on the viability of physicalism in the philosophy of mind ... 

Three featmes of these classical accoimts of reduction are worth emphasising. Firstly, intertheoretic reduction is a kind of subsmnption, in which a more generally applicable theory replaces one of more restricted application. Secondly, intertheoretic relationships may show how to correct the laws of the reduced theory, as when the atomic theory showed how to correct the ideal gas laws to reflect the molecular structure of gases, via the van der Waals equation of state. Thus the laws of the reduced theory may be recovered only approximately. Thirdly, because reduction is an intertheoretic relation, the reduction of one disciphne (or domain ) by another is a scientific achievement seemed at some specific time, when theories with the requisite explanatory resources become available. 

I suspect that the status of chemistry as the middle science makes it especially fertile ground for the development of hybrid representation schemes that function explicitly as inferential tools. Consider, for example, chemical equations, Lewis structures, the periodic table, and reaction mechanism diagrams. In each case there is a rich story of novel representation in the face of complexity. We would do well to consider in a more systematic manner how such representation schemes can be robust inferential tools, how issues of representation are related to explanatory power, and how recognition of amalgamated concepts might influence our accounts of reduction and intertheoretic relations more generally. 

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