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Philosophical Mechanics in the Age of Reason

Katherine Brading and Marius Stan

Out now with Oxford University Press

This is a book about the uneasy --  yet inextricable -- entanglement between matter theory, mechanics, metaphysics, and physics during the 18th century, in the wake of Descartes's Principles of Philosophy, Newton's Principia, and Leibniz's papers on dynamics.

Why "philosophical mechanics"? See here and here.

The first half of our book (see here for more) follows the attempts of leading 18th century philosophers from across Europe to provide an account of collisions between bodies. Descartes had placed collisions at the heart of matter theory, thereby opening up a dizzying array of questions including:

  • What are the correct rules of collision?

  • What is the process by which one body acts on another?

  • What are the properties of bodies?

  • Do bodies have inherent force?

  • And above all: How can we know about any of this?


From Malebranche to Du Châtelet in France, from the English Newtonians (such as Keill) to the Dutch (such as Musschenbroek), from Wolff in Germany to Hermann in St. Petersburg, an urgent search was underway for an account of collisions that successfully integrated matter theory with mechanics.

The second half of our book follows another strand of philosophical mechanics, whose leading figures include the Bernoullis, Maupertuis, Euler, d'Alembert and Lagrange. The primary focus in this second strand is the development and enlargement of rational mechanics, a project that is intertwined -- inevitably -- with questions about the material basis of the subject-matter of mechanics and the epistemological justification of its principles.

Unifying the whole is the struggle to solve the problem of bodies.


The failure of the eighteenth century to arrive at a successful philosophical mechanics, with a single all-encompassing account of bodies, has serious ramifications throughout philosophy.

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