I get the whole argument of traveling over vast distances between neighboring stars. There are some enormous technological hurdles for us to get a man just across the solar system. But we've only been flying for like ~100 years. Human civilization is what, 8000 or so years old? So in just over 1% of the time we've been "advancing" we have driven the technology to put man into space. I just don't think we have a grasp of what is possible in say another 8000 years. As long as we don't blow ourselves up...