This paper presents the view that tropes can change, and so are not individuated by their determinate qualitative characters. On the view I have in mind, a trope is at any given time fully determinate, but can change qualitatively within the bounds set by a determinable essence. A charge trope, for example, must at any time have some exact intensity, but can survive changes in intensity. My argument, roughly, is this: Objects can change, and tropes are the parts of objects that change (in a special sense of ‘part’), so tropes can change too. After some preliminaries, I present the argument carefully and discuss the operant notions. I then discuss each premise in turn. I respond to the charge that the view isn't realist, and to objections based on identity-conditions for tropes. I describe both substratum- and bundle-theoretic versions of the view, and finally, show what the view buys us.

中文翻译：

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比喻和质变

本文提出的观点是，比喻可以改变，因此不会因其确定的定性特征而个性化。根据我的观点，比喻在任何给定时间都是完全确定的，但可以在可确定的本质所设定的范围内发生质的变化。例如，电荷比喻在任何时候都必须具有某种精确的强度，但可以承受强度的变化。我的论点大致是这样的：对象可以改变，而比喻是对象变化的部分（在“部分”的特殊意义上），所以比喻也可以改变。经过一些准备后，我仔细地提出了论点并讨论了操作性的概念。然后我依次讨论每个前提。我回应了这种观点不现实的指控，以及基于比喻的身份条件的反对意见。