In my aging years, I've become more and more cynical of any definition that we might put forth regarding what's intelligent out there, because, of course, we define “ourselves” as intelligent. And I ask myself what even gives us that right to judge ourselves to be intelligent. We're coming up with our own definitions and so, of course we're going to look pretty good compared with other animals in the world. But you can imagine some species vastly more intelligent than we are… Why should we think we even have any hope of communicating with them? Consider that we haven't had a meaningful conversation with any other species of life on earth with whom we have DNA in common.
~ Neil deGrasse Tyson