Forty years ago, Gould and Lewontin used the metaphor of a building's “spandrels” to highlight that organismal traits could be the inevitable consequence of organismal construction, with no alternative configurations possible. Because adaptation by natural selection requires variation, regarding a trait incapable of variation as an adaptation could be a serious error. Gould and Lewontin's exhortation spurred biologists’ efforts to investigate biases and limitations in development in their studies of adaptation, a major methodological advance. But in terms of the metaphor itself, over the past 40 years there are virtually no examples of “spandrels” in the primary literature. Moreover, multiple serious confusions in the metaphor have been identified and clarified, for example, that the “spandrels” of San Marco are pendentives, and pendentives are perfect examples of adaptation. I look back over the sparse empirical fruits of the “spandrels” metaphor, and ask what the clarifications of the past 40 years mean for biological theory and practice. I conclude that if there is anything to be rescued from the clarified spandrels metaphor, it is not “constraint” at all. Instead, it is the still‐unresolved issue of trait delimitation, which is how to parse organisms into subsets that are tractable and biologically appropriate for study.

中文翻译：

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流氓和特质的界定：没有“建筑约束”之类的东西。

四十年前，古尔德（Gould）和莱沃汀（Lewontin）用建筑物“废料桶”的比喻来强调，有机特性可能是有机建筑的必然结果，没有其他可能的配置。由于通过自然选择进行的适应需要变异，因此将无法变异的特征视为适应可能是一个严重的错误。古尔德（Gould）和勒沃汀（Lewontin）的劝告促使生物学家努力研究适应性研究中发展方面的偏见和局限性，这是方法学的重大进步。但是就隐喻本身而言，在过去的40年中，基本文献中几乎没有“流浪汉”的例子。此外，已经发现并澄清了隐喻中的多个严重混淆，例如，圣马可的“流浪汉”是沉思者，悬念是适应的完美例子。我回顾了“流浪汉”隐喻的经验稀疏成果，并询问过去40年的澄清对于生物学理论和实践意味着什么。我得出的结论是，如果有什么要从澄清的跨度隐喻中解脱出来，那根本不是“约束”。取而代之的是，特质划界问题仍未解决，即如何将生物体解析成易于处理且生物学上适合研究的子集。