In the light of his recent (and fully deserved) Nobel Prize, this pedagogical paper draws attention to a fundamental tension that drove Penrose’s work on general relativity. His 1965 singularity theorem (for which he got the prize) does not in fact imply the existence of black holes (even if its assumptions are met). Similarly, his versatile definition of a singular space–time does not match the generally accepted definition of a black hole (derived from his concept of null infinity). To overcome this, Penrose launched his cosmic censorship conjecture(s), whose evolution we discuss. In particular, we review both his own (mature) formulation and its later, inequivalent reformulation in the pde literature. As a compromise, one might say that in “generic” or “physically reasonable” space–times, weak cosmic censorship postulates the appearance and stability of event horizons, whereas strong cosmic censorship asks for the instability and ensuing disappearance of Cauchy horizons. As an encore, an “Appendix” by Erik Curiel reviews the early history of the definition of a black hole.

鉴于他最近（也是当之无愧的）诺贝尔奖，这份教学论文提请人们注意引起彭罗斯关于广义相对论的基本张力。他于1965年提出的奇异性定理（尽管获得了大奖）实际上并不意味着存在黑洞（即使满足其假设）。同样，他对奇异时空的通用定义与黑洞的普遍接受定义不匹配（源自他的零无穷大概念）。为了克服这一点，彭罗斯（Penrose）提出了他的宇宙审查猜想，我们将讨论其演变。特别是，我们既查看自己的（成熟）的制定和其后来，在不等价再形成PDE文学。作为一种折衷，人们可能会说，在“一般”或“物理上合理”的时空中，弱的宇宙审查制度假设事件层的出现和稳定性，而强的宇宙审查制度要求柯西层的不稳定和随之而来的消失。作为重头戏，埃里克·库里尔（Erik Curiel）撰写的“附录”回顾了黑洞定义的早期历史。