What does it mean for a hypothesis to be ad hoc? One prominent account has it that ad hoc hypotheses have no independent empirical support. Others have viewed ad hoc judgements as subjective. Here I critically review both of these views and defend my own Coherentist Conception of Ad hocness by working out its conceptual and descriptive attractions.

The history of the Parallelogram Rule for composing physical quantities, such as motions and forces, is marked by conceptual difficulties leading to false starts and halting progress. In particular, authors resisted the required assumption that the magnitude and the direction of a quantity can interact and are jointly necessary to represent the quantity. Consequently, the origins of the Rule cannot be traced to Pseudo-Aristotle or Stevin, as commonly held, but to Fermat, Hobbes, and subsequent developments in the latter part of (...) the seventeenth century. (shrink)

William Gilbert’s 1600 book, De magnete, greatly influenced early modern natural philosophy. The book describes an impressive array of physical experiments, but it also advances a metaphysical view at odds with the soon to emerge mechanical philosophy. That view was animism. I distinguish two kinds of animism – Aristotelian and Platonic – and argue that Gilbert was an Aristotelian animist. Taking Robert Boyle as an example, I then show that early modern arguments against animism were often effective only against Platonic (...) animism. In fact, unacknowledged traces of Aristotelian animism can be found in Boyle’s mechanical account of nature. This was Gilbert’s legacy. (shrink)

In A Treatise of Artificial Magnets, John Michell observes, Not being aware of this property [i.e. the equality of attraction and repulsion], he [Gilbert] concluded from some experiments he had made, not very irationally [sic], that the Needle was not attracted by the magnet, but turned into its position by, what he calls, a disponent virtue […]. For Michell, the disponent virtue 1 is the underlying cause of magnetic phenomena in Gilbert’s treatment. He is not alone. Ridley and Carpenter also (...) read Gilbert’s magnetism as positing a disponent virtue.2 I agree. In this paper, I show what it would entail to treat Gilbertian magnetism as... (shrink)

Galileo proposed what has been called a proto-inertial principle, according to which a body un horizontal motion will conserve its motion. This statement is only true in counterfactual circumstances where no impediments are present. This paper analyzes how Galileo could have been justified in ascribing definite properties to this idealized motion. This analysis is then used to better understand the relation of Galileo’s proto-inertial principle to the classical inertial principle.

This dissertation draws upon historical studies of scientific practice and contemporary issues in the metaphysics and epistemology of science to account for the nature of physical quantities. My dissertation applies this integrated HPS approach to dimensional analysis—a logic for quantitative physical equations which respects the distinct dimensions of quantities (e.g. mass, length, charge). Dimensional analysis and its historical development serve both as subjects of study and as a sources for solutions to contemporary problems. The dissertation consists primarily of three related (...) papers on: (1) the methodological and metaphysical foundations of dimensional analysis, (2) the use of dimensional analysis in determining physical symmetries, (3) the use of dimensional analysis in securing metrological extension. (shrink)

Francis Bacon’s natural philosophy contains a whole series of interconnected concepts related to extension, such as “borders,” “leaps” and “orbs of virtue”. These Baconian concepts are still not fully understood and are in need of a detailed analysis. They do not derive from a general conception of physical or mathematical space, and are not explainable in terms of parts of matter and aggregates. Instead, they are somewhat mysteriously defined in terms of limits and boundaries of action. This article offers a (...) contextual investigation of Bacon’s extension relating concepts. I show that in adopting a particular strategy of deriving spatial properties and extension related concepts from a theory of action and force, Bacon follows in the footsteps of Gilbert’s magnetic philosophy. However, in contrast to the more traditional approaches of William Gilbert, Giovan Battista della Porta and Johannes Kepler, Bacon strips his extension-related concepts from most natural philosophical content and argues for a methodologically driven approach, leading to operational definitions. (shrink)