With the careful use of the polywater episode in the history of chemistry as a case study, I will show that the distinction recently made in the philosophy of science between experimenting on an entity and manipulating that entity is best seen as a distinction between experimenting on, and experimenting with, that entity. The polywater case also reveals that Ian Hacking's 1983 manipulability criterion is not a necessary condition for realism, and that scientists can, and do, justifiably change their minds (...) as to the reality of theoretical entities. (shrink)

In this sequence of philosophical essays about natural science, the author argues that fundamental explanatory laws, the deepest and most admired successes of modern physics, do not in fact describe regularities that exist in nature. Cartwright draws from many real-life examples to propound a novel distinction: that theoretical entities, and the complex and localized laws that describe them, can be interpreted realistically, but the simple unifying laws of basic theory cannot.

Quantum systems have a holistic structure, which implies that they cannot be divided into parts. In order tocreate (sub)objects like individual substances, molecules, nuclei, etc., in a universal whole, the Einstein-Podolsky-Rosen correlations between all the subentities, e.g. all the molecules in a substance, must be suppressed by perceptual and mental processes.Here the particular problems ofGestalt (shape)perception are compared with the attempts toattribute a shape to a quantum mechanical system like a molecule. Gestalt perception and quantum mechanics turn out (on an (...) informal level) to show similar features and problems: holistic aspects, creation of objects, dressing procedures, influence of the observer, classical quantities and structures. The attribute classical of a property or structure means thatholistic correlations to any other quantity do not exist or that these correlations are considered as irrelevant and therefore eliminated (either deliberately and by declaration or in a mental process that is not under rational control). An example of animposed classical structure is the nuclear frame of a molecule. Candidates for classical properties that arenot imposed by the observer could be the charge of a particle or the handedness of a molecule. It is argued here that at least part of a molecule's shape can begenerated automatically by the environment. A molecular shape of this sort arises in addition to Lamb shift-type energy corrections. (shrink)

This 1983 book is a lively and clearly written introduction to the philosophy of natural science, organized around the central theme of scientific realism. It has two parts. 'Representing' deals with the different philosophical accounts of scientific objectivity and the reality of scientific entities. The views of Kuhn, Feyerabend, Lakatos, Putnam, van Fraassen, and others, are all considered. 'Intervening' presents the first sustained treatment of experimental science for many years and uses it to give a new direction to debates about (...) realism. Hacking illustrates how experimentation often has a life independent of theory. He argues that although the philosophical problems of scientific realism can not be resolved when put in terms of theory alone, a sound philosophy of experiment provides compelling grounds for a realistic attitude. A great many scientific examples are described in both parts of the book, which also includes lucid expositions of recent high energy physics and a remarkable chapter on the microscope in cell biology. (shrink)