Interesting discussion about intelligence and aliens with Richard Dawkins and Neil Degrasse Tyson.

Tyson makes a point I used to make as a kid.  Why do aliens in movies always look so humanlike?  But then he makes a less valid point.  If intelligence is such an inevitable consequence of evolution, why are humans the only life on Earth with advanced cognition.  Dawkins provides no good answer.

The answer, in my humble opinion, is that the human mind is the most complex known object in the universe, and thus takes billions of years to evolve.  Further, to reach our level of intelligence, you almost need a four legged animal with hands to become bipedal, because only then are the hands free to create and use tools.  This probably also explains why intelligent life, even if evolved from dinosaurs, would look like us: