pitt hps graduate student wip talks

The graduate students in the History and Philosophy of Science department at the University of Pittsburgh host regular Work in Progress talks to share ideas, get feedback, and promote community.

Talks are held in Room G28 of the Cathedral of Learning. While talks are not generally open to the public, exceptions can be made: Please contact Bryan Roberts if you are interested in attending an upcoming talk.
 

Next WIP Talk

2009 March 6 at 4:30 pm
Newton's Empiricism and the Changing Metaphysics of Void Space
Zvi Biener

In definitions written for possible inclusion in the third edition of Book III of the Principia, Newton defined both “body” and “vacuum” in terms of resistance: body is that which gives resistance, vacuum is the place in which body can move without resistance. Curiously, Newton was vehement that these definitions were not the only possible definitions of body and vacuum, but merely the ones with which he was concerned in the Principia. About “other sorts of bodies and another sort of void”, he wrote, “let authors in other sciences dispute”. This admission is stunning. Newton had struggled throughout his career to precisely define ‘body’ and ‘void’. But while he had often relativized his concept of body to the project of the Principia—other physical theories may hypothesize other sorts of bodies—until these draft definitions he had never done so for the concept of void. In fact, in the earlier anti-Cartesian De Gravitatione, he even portrayed his account of void space as the only metaphysically possible one!

I argue that these definitions—as well as a small change in the scholium on space and time—betray a subtle change in Newton’s metaphysics of void space. In particular, I argue that Newton began to question a claim he had initially articulated in De Gravitatione ; namely, that void space was lacking all agency and thus categorically distinct from substance. This change was caused by a co-relative change in the epistemic status of void space vis-a-vis Newtonian mechanics.

These claims are supported by two threads of argumentation. First, I show that Newton’s conception of space in both De Gravitatione and the scholium on space and time was supported by an argument concerning the geometrical structure of space as well as an argument concerning space’s lack of agency. Although the two arguments are intertwined, they are methodologically independent. While the first concerns the conceptual necessity of absolute space’s geometry for physical theory, the second concerns empirical evidence regarding the vacuity of the celestial spaces. Because of this methodological independence, when in the 1710s Newton came to doubt the validity of his arguments concerning the vacuity of space (expressed in revisions to Prop. 6 of Book III of the Principia), he could question whether space was necessarily inert without throwing into doubt space’s geometrical structure. Space's lack of agency, however, was also used in De Gravitatione to support the ontological necessity of space. It was on the basis of this inertness and the claim that substance is “an entity that can act” that Newton argued for space’s being “neither substance nor accident” and so a necessary, divine emanation. Thus, when he began to doubt the vacuity of the celestial spaces, he was also committed to rethinking his position regarding space as an emanative effect.

The second thread of argumentation concerns Newton’s preferred method of reasoning in natural philosophy. Newton often claimed that his method is that “of the geometers”. On this method, terms are used only in accordance with their precise definitions. Their vulgar use, if it exists, is ignored . However, in De Gravitatione and the scholium Newton avoided using this method in his treatment of space. In fact, in the first two edition of the Principia he explicitly held that since “time, space, place, and motion” are “very well known to all”, he shall not define them. Rather, in order to treat space Newton followed a common dialectical strategy: he took a familiar (if not precise) concept and showed through a series of arguments what could and could not be properly said of it. For Newton, the concept of space was thus the same as that of his predecessors, but cleansed of their errors and misconceptions. Yet Newton’s treatment of space changed in the 1710s. During this period, because of his increasing doubts regarding the nature of void space, Newton came to believe that space itself must be subjected to “the method of the geometers”. On Newton’s understanding of this method, foundational theoretical terms (like “space”) are not defined a priori, but are defined a posteriori through the machinery of physical theory. This relativizes their application to the scope of the physical theory in question. Because of this understanding of the “manner of the geometers”, Newton's concept of space ceased to have a general, metaphysical application (as it did in De Gravitatione) and became relativized to the framework of the Principia.

upcoming wip talks

March 6, 2009:
Zvi Biener
(abstract)

February 27, 2009:
Bryan Roberts
(abstract)

February 27, 2009:
Julia Bursten
(abstract)

February 20, 2009:
Jonathan Livengood
(abstract)

February 13, 2009:
Tom Pashby
(abstract)

January 9, 2009:
Peter Gildenhuys
(abstract)