Copernican reasoning involves considering ourselves, in the absence of other information, to be randomly selected members of a reference class. Consider the reference class intelligentobservers. If there are extraterrestrial intelligences (ETIs), taking ourselves to be randomly selected intelligent observers leads to the conclusion that it is likely the Earth has a larger population size than the typical planet inhabited by intelligent life, for the same reason that a randomly selected human is likely to come from a more populous country. The astrophysicist Fergus Simpson contends that this reasoning supports the claims that the typical planet inhabited by ETIs is smaller than Earth (radius $$\approx$$ 5000 km; cf. Earth’s radius = 6371 km) and that the typical ETI is significantly larger than us ($$\approx$$ 314 kg, the size of an adult male grizzly bear). Simpson’s applications of Copernican reasoning are novel and exciting. They should be of interest to philosophers concerned with Richard Gott’s delta t argument, the N = 1 problem in astrobiology, limited principles of indifference, and probabilistic epistemology in general. While we agree with Simpson about the qualitative direction of his conclusions, we take issue with his presentation of precise quantitative results because his methods (1) display bias, (2) ignore other variables contributing to population size, (3) commit an equivocation, and (4) conceal their dependence on arbitrary assumptions.

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关于智能外星人的哥白尼推理：对辛普森的答复

哥白尼推理涉及在没有其他信息的情况下将我们自己视为参考类中随机选择的成员。考虑参考类智能观察者。如果存在外星智能（ETI），将我们自己当作随机选择的智能观察者会得出这样的结论：地球的人口规模可能比典型的智慧生命居住的行星还要大，原因与随机选择的人类相同可能来自人口较多的国家。天体物理学家弗格斯·辛普森 (Fergus Simpson) 争辩说，这种推理支持了 ETI 居住的典型行星比地球小（半径 $$\approx$$ 5000 公里；参见地球半径 = 6371 公里）并且典型的 ETI 明显大于地球的说法。我们（$$\约$$ 314 公斤，成年雄性灰熊的大小）。辛普森对哥白尼推理的应用既新颖又令人兴奋。关心理查德·戈特 (Richard Gott) 的 delta t 论证、天体生物学中的 N = 1 问题、有限的冷漠原则和一般的概率认识论的哲学家应该会对它们感兴趣。虽然我们同意辛普森关于他结论的定性方向，但我们对他提出的精确定量结果提出异议，因为他的方法 (1) 显示偏差，(2) 忽略其他影响人口规模的变量，(3) 模棱两可， (4) 隐藏他们对任意假设的依赖。有限的冷漠原则和一般的概率认识论。虽然我们同意辛普森关于他结论的定性方向，但我们对他提出的精确定量结果提出异议，因为他的方法 (1) 显示偏差，(2) 忽略其他影响人口规模的变量，(3) 模棱两可， (4) 隐藏他们对任意假设的依赖。有限的冷漠原则和一般的概率认识论。虽然我们同意辛普森关于他结论的定性方向，但我们对他提出的精确定量结果提出异议，因为他的方法 (1) 显示偏差，(2) 忽略其他影响人口规模的变量，(3) 模棱两可， (4) 隐藏他们对任意假设的依赖。