Charles Darwin’s On the Origin of Species has an unusual format. After presenting his theory of Natural Selection in its first four chapters, there follows a series of five chapters presenting a large number of problems and objections to the theory which, he admits, appear overwhelming. Not until chapter 10 does he begin to present what he takes to be the positive evidence for his theory. In this paper I trace the evolution of this structure from its first hints in his Species Notebooks , through the 1842 Sketch and 1844 Essay to the Origin, showing that it reflects a growing awareness on Darwin’s part of what I call ’In Principle Impossible’ arguments against his theory, and of a systematic strategy for disarming them.

查尔斯·达尔文的《物种起源》有一种不同寻常的格式。在前四章介绍了他的自然选择理论之后，接下来的五章系列提出了对该理论的大量问题和反对意见，他承认这些问题似乎势不可挡。直到第 10 章，他才开始提出他认为是他理论的积极证据的东西。在本文中，我从他的《物种笔记本》中的第一次暗示，到 1842 年的草图和 1844 年的《起源论文》，追溯了这种结构的演变。，这表明它反映了达尔文对我所说的反对他的理论的“原则上不可能”的论点以及解除这些论点的系统策略的日益认识。