Originally Posted by Chip

Actually, this could also be incorrect. The Fermi Paradox is based on a notion of alien "civilizations" that conform to our concepts of what a civilization is. As brilliant as Mr. Fermi was in many areas, he and his colleagues were discussing 1940s comic book aliens who, no matter how strange they were drawn, were essentially advanced reflections of us. Fermi failed to consider what "alien life" might actually be like. Because of this, in terms of our understanding of biology, one could just as easily imagine a galaxy teeming with advanced alien life and not one of them comes here or contacts us in all the years of human evolution so far. There is nothing in nature to preclude that or make it any less likely. It is no more likely or unlikely than rare aliens. Though we can make informed speculations based solely on our understanding of chemistry and biology on Earth, thus far the real answer about life elsewhere in the galaxy is: we don't know.

If one objects to this notion, then one has to introspect and admit that you are embracing a concept of aliens that think like us and are essentially reflections of us. But in reality, if they exist, they're aliens, so they are not obligated to be like us at all.