We all know that, nowadays, physics and philosophy are housed in separate departments on university campuses. They are distinct disciplines with their own journals and conferences, and in general they are practiced by different people, using different tools and methods. We also know that this was not always the case: up until the early 17th century (at least), physics was a part of philosophy. So what happened? And what philosophical lessons should we take away? We argue that the split took place long after Newton's Principia (rather than before, as many standard accounts would have it), and offer a new account of the philosophical reasons that drove the separation. We argue that one particular problem, dating back to Descartes and persisting long into the 18th century, played a pivotal role. The failure to solve it, despite repeated efforts, precipitates a profound change in the relationship between physics and philosophy. The culprit is the problem of collisions. Innocuous though it may seem, this problem becomes the bellwether of deeper issues concerning the nature and properties of bodies in general. The failure to successfully address the problem led to a reconceptualization of the goals and subject-matter of physics, a change in the relationship between physics and mechanics, and a shift in who had authority over the most fundamental issues in physics.

我们都知道，如今，物理学和哲学被分设在大学校园的不同系中。它们是不同的学科，有自己的期刊和会议，通常由不同的人使用不同的工具和方法来实践。我们也知道情况并非总是如此：直到 17 世纪初（至少），物理学还是哲学的一部分。所以发生了什么事？我们应该吸取哪些哲学教训？我们认为分裂发生在牛顿原理之后很久（而不是以前，正如许多标准账户所拥有的那样），并提供了一个关于推动分离的哲学原因的新账户。我们认为，一个可以追溯到笛卡尔并一直持续到 18 世纪的特殊问题发挥了关键作用。尽管反复努力，但未能解决它，却促使物理学与哲学之间的关系发生了深刻的变化。罪魁祸首是碰撞问题。尽管看起来无关紧要，但这个问题成为有关一般物体的性质和特性的更深层次问题的风向标。未能成功解决这个问题导致了对物理学目标和主题的重新概念化，物理学和力学之间关系的变化，以及谁对物理学中最基本的问题拥有权威的转变。