# Research Seminar: Robert DiSalle

## October 3 @ 12:00 pm - 2:00 pm

Robert DiSalle is a Professor in the Department of Philosophy at Western University and he is visiting the IHPST during 2018-2019. His research interests include the history and philosophy of physics from Newton to the present, philosophical problems of space and time, history of the philosophy of science from the 17th century to the present, and connections between philosophy of science and analytic philosophy. For more information about Professor DiSalle, visit his website at http://publish.uwo.ca/~rdisalle/ .

**The paper to be discussed:**

“On the method and metaphysics of mathematical physics”

For a copy of the paper, please contact Michael Miller (mike.miller@utoronto.ca).

**Abstract:**

Newton’s Principia was among the first examples, and eventually an ideal model, of what we now mean by “mathematical physics.” It is a challenge to understand, therefore, the view of some of his contemporaries that this work was only mathematics, and not physics at all. The explanation that is nearest to hand is that Newton’s approach set aside the pursuit of causal explanations: his contemporaries, dedicated to one or another form of the “mechanical philosophy,” would not recognize as a physical theory any mathematical account that, like Newton’s, provided no causal mechanism to explain its mathematical principles. Certainly some of Newton’s own remarks about the mathematical character of his work, and his disavowal of inquiry into the cause of gravity, seem to suggest such a view, and even suggested to later generations that he was a forerunner of logical empiricism. These views are not entirely unfounded. But they falsely suggest an abandonment, at the very commencement of mathematical physics, of the very idea of physical understanding in favour of mathematical precision and predictive success. This is is very far from Newton’s view of his work, its relation to the mechanical philosophy, and what it had achieved (and might achieve). On the contrary, Newton considered his use of mathematics in physics to be a new and indispensable method for identifying, and understanding, the action of physical causes.

Few of Newton’s contemporaries grasped the radical novelty of his mathematical method, and this explains some of the difficulties they had, not only in responding to his critique of mechanistic metaphysics, but also in grasping the metaphysical implications of his method. In the subsequent evolution of physics, however, the Newtonian conception, properly understood, illuminates the power and limitations of mathematical physics as a means of understanding as well as a tool for predicting. It sheds light on fundamental philosophical problems connected with the applicability of mathematics to the world, including questions about the nature of empiricism and realism regarding mathematical theories, that have preoccupied philosophers of post-Newtonian physics. The philosophical disagreement between Einstein and Bohr, for example, can be illuminated by this conception, for the debate rests significantly on questions about the role of mathematical formalism as a source of physical understanding. The most prominent approaches to these questions appear to be forms of “structural realism” and anti-realism; the conception that originated with Newton is a compelling alternative view of what mathematical formalism can discover about physical reality.