Online research in philosophy

This paper suggests that the cases made for atoms and the aether in nineteenth-century physical science were analogous, with the implication that the case for the atom was less than compelling, since there is no aether. It is argued that atoms did not play a productive role in nineteenth-century chemistry any more than the aether did in physics. Atoms and molecules did eventually find an indispensable home in chemistry but by the time that they did so they (...) were different kinds of entities to those figuring in the speculations of those natural philosophers who were atomists. Advances in nineteenth-century chemistry were a precondition for rather than the result of the productive introduction of atoms into chemistry. (shrink)

Proclus defends the Platonic view that the heavens consist in (the highest gradations) of all four elements. He attacks Aristotle's view that the heavens consist in a distinct, fifth element.

The quantum vacuum may in certain circumstances be regarded as a type of fluid medium, or aether, exhibiting energy density, pressure, stress and friction. Vacuum friction may be thought of as being responsible for the spontaneous creation of particles from the vacuum state when the system is non-stationary. Examples include the expanding universe, rotating black holes, moving mirrors, atoms passing close to surfaces, and the activities of sub-cellular biosystems. The concept of vacuum friction will be reviewed and illustrated, and (...) some suggestions for future experiments made. (shrink)

I. Introduction Siris, Berkeley's last major work, is undeniably a rather odd book. It could hardly be otherwise, given Berkeley's aims in writing it, which are three-fold: 'to communicate to the public the salutary virtues of tar-water,'1 to provide scientific background supporting the efficacy of tar-water as a medicine, and to lead the mind of the reader, via gradual steps, toward contemplation of God.2 The latter two aims shape Berkeley's extensive use of contemporary natural science in Siris. In particular, Berkeley's (...) focus on what he calls fire (or aether or light) as a quasiuniversal 'cause' of natural change3 serves these purposes, for the 'activity' of the aether, in his view, can both explain the miraculous virtues of a certain medicine, i.e. tar-water, and reveal God's action and his divine order.4 Berkeley's corpuscular speculations, including his use of fire-theory, are not especially idiosyncratic as natural philosophy. In his theorizing, as Jessop and other have noted, he is heavily indebted to the work of Hermann Boerhaave, the Dutch chemist, botanist, and physician whose teachings were highly influential in mid-eighteenth century Britain.5 Boerhaave, along with other Dutch natural philosophers cited by Berkeley, assigned a central role in accounting for physio-chemical activity to fire, a subtle, insensible particulate substance, sometimes identified with light. (shrink)

After a consideration of Reichenbach's and Winnie's axiomatizations of Special Relativity, three synchrony-free axioms which can be used to simultaneously axiomatize Special Relativity, Classical Aether Theory, and a threefold continuum of theories in between are suggested. The specific theory obtained from the axioms depends on the value of a parameter in each axiom. It is shown that the values of the three parameters are empirically determined by the Michelson-Morley, Kennedy-Thorndike, and Ives-Stilwell experiments.

Grunbaum has argued that the Lorentz-Fitzgerald contraction hypothesis is not ad hoc since the Kennedy-Thorndike experiment can be used to provide a test that is significantly different from that provided by the Michelson-Morley experiment. In the first part of the paper, I show that the differences claimed by Grunbaum to hold between these two experiments are not sufficient for establishing independent testability. A dilemma is developed: either the Kennedy-Thorndike experiment, because of experimental realities, cannot test the uncontracted Fresnel aether (...) theory, or if experimental difficulties are ignored, the Kennedy-Thorndike experiment degenerates into a version of the Michelson-Morley experiment. The second part of the paper is a feasibility study of the prospects for defining experimental types according to aims of measurement and determination. This approach is applied to the contraction hypothesis, where it is suggested that the usual analysis of independent testability be modified. (shrink)

High-level study discusses Newtonian principles and 19th-century views on electrodynamics and the aether, covers Einstein’s electrodynamics of moving bodies, Minkowski geometry and other topics. A rich exposition of the elements of the Special and General Theory of Relativity.