论文标题
关于观察外层次文明的可能性：自我指示假设的预测
On the Likelihood of Observing Extragalactic Civilizations: Predictions from the Self-Indication Assumption
论文作者
论文摘要
可以从宇宙学距离观察到雄心勃勃的文明，这些文明可以从宇宙学的距离观察到资源，但是我们可以看到一个人的可能性呢？问题归结为估计宇宙中这种事物的外观速率 - 一种根本不确定的数量。尽管以前的不确定性，但人类的考虑会引起贝叶斯的更新，从而导致预测。自我采样假设（SSA）是人类概率的学校，以前已用于此目的。在这里，我们从替代学校，自我指标假设（SIA）中得出预测，并指出其特征。 SIA偏爱更高的扩张主义生活率，但是我们在当前的宇宙时代的存在意味着这种生活不能太普遍（否则我们的银河系很久以前就已经被超越了）。这种组合将我们的较大不确定性挤压为几个数量级。背景宇宙学的细节掉了，我们得到了一些明显的结论。例如。如果技术的限制允许文明以速度$ V $扩展，那么在过去的光锥上可以看到至少一个扩展宇宙学文明的可能性为$ 1- \ frac {v^3} {c^3} $。我们还展示了如何从假设的全套调查的结果中更新SIA估计值，该调查检测到扩展文明的“ $ n $”（以$ n \ geq 0 $），并计算宇宙中隐含的最终寿命。
Ambitious civilizations that expand for resources at an intergalactic scale could be observable from a cosmological distance, but how likely is one to be visible to us? The question comes down to estimating the appearance rate of such things in the cosmos --- a radically uncertain quantity. Despite this prior uncertainty, anthropic considerations give rise to Bayesian updates, and thus predictions. The Self-Sampling Assumption (SSA), a school of anthropic probability, has previously been used for this purpose. Here, we derive predictions from the alternative school, the Self-Indication Assumption (SIA), and point out its features. SIA favors a higher appearance rate of expansionistic life, but our existence at the present cosmic time means that such life cannot be too common (else our galaxy would long ago have been overrun). This combination squeezes our vast prior uncertainty into a few orders of magnitude. Details of the background cosmology fall out, and we are left with some stark conclusions. E.g. if the limits to technology allow a civilization to expand at speed $v$, the probability of at least one expanding cosmological civilization being visible on our past light cone is $1-\frac{v^3}{c^3}$. We also show how the SIA estimate can be updated from the results of a hypothetical full-sky survey that detects "$n$" expanding civilizations (for $n \geq 0$), and calculate the implied final extent of life in the universe.
