Two characteristics distinguish quantities from non-quantitative properties and relations. First, every quantity is associated with a class of determinate “magnitudes” or “values” of that quantity, each member of which is a property or relation itself. So when a particle possesses mass or charge, it always instantiates one particular magnitude of mass or charge — like 2.5 kilograms or 7 Coulombs. Second, the magnitudes of a given quantity (alternatively, the particulars which instantiate those magnitudes) exhibit “quantitative structure”, which comprises things like: ordering structure, summation/concatenation structure, ratio structure, directional structure, etc. We often represent quantities using similarly-structured mathematical entities, like numbers, vectors, etc.

The Metaphysics of Quantity conference is a three day conference to be held at the New York University Philosophy Department, with support from the New York Institute of Philosophy, on the weekend of May 1st through May 3rd, 2015. The purpose of this conference is to showcase new work being done in this exciting subfield, which investigates the nature of, and the philosophical issues stemming from, quantities. For more about the range of topics covered, and for information on how to submit a talk for this conference, please see our Call For Papers. To register, click here.