The path of species is clear: achieve a niche in an ecosystem, then solidify it, and at that point, seek new territory. When you have dominated the world, like flies or orchids, you know it is time for a new goal.
As it turns out, the night sky reveals one, an infinite space outside this planet. This is a convenient goal since our planet is vulnerable to comet strikes, sun implosion and other forms of instability that would terminate all life. We must take to space if we want to live for the long term.
The questions “why have we not taken to the stars?” and “why are there no aliens among us?” have the same answer. First, witness the framework to the question:
As the philosopher Nick Bostrom explains, this idea suggests there are several “evolutionary transitions or steps” that life on an Earth-like planet has to achieve before it can communicate with civilizations in other star systems. But an obstacle or barrier may make it impossible for an intelligent species like ours to get through all those steps. That would explain why we haven’t heard from or seen any other life.
In other words, there are pitfalls and thresholds that any species must overcome in order to take to the stars, and these may occur after the necessary technologies are developed.
The biggest pitfalls are on our planet: can we achieve a stable social order so that we can send people to the stars? And if we do, can we motivate them with something stronger than self-interest, so that they carry on in order that generations far removed from them are the ones who benefit? Do they have an identity strong enough to compel them to do so?
Our only hope lies in something that bonds us to past and future at a level higher than either the individual or the hive/collective. This requires a strong sense of identity and purpose, the type that only comes with national identity. Nothing else can bond us.
Most likely, civilizations all decay the same way, which is to lose site of their purpose, and therefore to include Others as a means to the ends of those in power. This keeps them from exploring the stars: they are not strongly bonded enough and fragment upon encountering the challenges of deep space.
If we wish to survive as a species, our hope lies within strongly bonded national groups who are ready to explore the stars without bringing everyone else along.