Ultimately, we are all alone. Each of us has relationships with other human beings, but we are still alone in our heads. Since we have no idea what is beyond the small parts of space that we can locate and search at a distance, it is hard to say that we are the only intelligent species in space. If we exist, why couldn’t another planet be inhabited with what we would call an intelligent species? It might be farther away than we can reach, and they may not have technology advanced enough to reach us either.