Fermi paradox

You can google it for more details, maybe you can find the wikipedia page if you are curious enough. Anyway, put it in a simple way, the paradox is talking about the contradiction between the reality that we have not met any aliens and the high probability there should be so many aliens in the cosmos because the universe is so big.

It occurs to me that when a society becomes more civilized, it kind of loses the impulse to invade as one way of exploration. You need to treat all those living things equally because you can see the tendency that we treat with each other more fairly no matter who you are, where you come from, or what are you. In the end, everyone lives happily in their chambers and forgets the big universe exists.

Or maybe, there could be a pandemic out there in the universe, everyone during this period of time needs to stay low and keep quiet. It is equivalent to the dark forest theory I know. But the twist here is that the pandemic can end, and it will.