There is an asymmetry in Newton's Principia between the status of rods and that of clocks. This can be seen by considering issues highlighted by Harvey Brown in his book Physical Relativity, in which he emphasizes the importance of thinking carefully about the relationships between themetrics of space and time, the spatial and temporal behaviors of rods and clocks, and dynamics. Brown's book focuses primarily on Einstein's theories of relativity, but the general lesson applies more widely. In this paper, I examine the status of rods and clocks in Newton's Principia. I argue that rods are geometrical whereas clocks are dynamical (section 2), in a sense to be explained, and comment on some aspects of this asymmetry that I find interesting (section 3). I am not suggesting that there is, in fact, an asymmetry in how rods and clocks should be treated, nor that Newton thought that there was. On the contrary, Newton sought a dynamical treatment of both rods and clocks. Nevertheless, for the purposes of the Principia, rods do not receive a dynamical treatment, do not need to receive dynamical treatment, and (given the resources of the Principia) would struggle to get such a treatment. The same is not true for clocks.

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关于牛顿原理的钟表笔记

牛顿原理中的杆状和钟状之间是不对称的。可以通过考虑Harvey Brown在他的《物理相对论》一书中强调的问题来看出这一点，他在书中强调了仔细考虑时空的度量指标，杆和钟的时空行为以及动力学之间的关系的重要性。布朗的书主要侧重于爱因斯坦的相对论，但总的教训适用范围更广。在本文中，我研究了牛顿原理中杆和钟的状态。在某种意义上，我认为杆是几何的，而钟是动态的（第2节），并就我发现有趣的这种不对称的某些方面发表评论（第3节）。我并不是说实际上有 杆和钟的处理方式不对称，牛顿也认为没有。相反，牛顿寻求对杆和钟的动力处理。然而，出于原理的目的，棒不接受动力治疗，不需要接受动力治疗，并且（鉴于原理的资源）将难以获得这种治疗。时钟不一样。