Even if our messages are unlikely to be heard, the threat to our species that contact with extrasolar entities poses means that determining what content to include in Messaging Extraterrestrial Intelligence (METI) messages presents serious ethical questions. I tackle one of those questions: Should our opening move in interstellar diplomacy be a peaceful overture or a belligerent warning?

Those in favor of broadcasting peaceful overtures sometimes argue that the ability to interpret a METI message requires advanced technology and communicative skills, which in turn depends on a suite of social capacities and prosocial attitudes. We can thus assume that any species which receives our message will at least be open to peaceful coexistence.

I show that this argument does not hold up under scrutiny because it seriously underestimates just how different an advanced alien intelligence could be from Earth life. An extraterrestrial entity might be similar to us: a society composed of cooperating autonomous individuals. But it could also be an instance of eusocial hive cooperation, or an evolving superindividual, which develops not through natural selection but through learning. These possibilities blow some of the premises of the argument for peaceful overture out of the water.

I conclude by making a case that, if we send any message at all, defensive belligerence is the more prudent diplomatic tactic, even in case of serious technological asymmetry.

即使不太可能听到我们的消息，但与外星体接触的物种对我们的物种构成的威胁也意味着，确定要在外星智能消息（METI）消息中包含哪些内容会带来严重的道德问题。我要解决一个问题：我们在星际外交中的开放举动是和平的序曲还是好战的警告？

那些赞成广播和平序曲的人有时认为，解释METI消息的能力需要先进的技术和沟通技巧，而这又取决于一系列的社会能力和亲社会态度。因此，我们可以假设，任何收到我们信息的物种将至少对和平​​共处持开放态度。

我证明了这一论点并没有受到严格的审查，因为它严重低估了先进的外星情报与地球生命有何不同。一个外星人的实体可能与我们相似：一个由相互协作的自治个人组成的社会。但是，这也可能是完全社会性的一个实例蜂巢合作，还是一个不断发展的超个人的，它通过自然选择，而是通过学习发展不是。这些可能性为和平序曲的争论提出了一些前提。

最后，我提出一个理由，即如果我们发送任何信息，即使在严重的技术不对称的情况下，防御性的交战也是更为谨慎的外交策略。