I was watching The Great Courses, "The Inexplicable Universe," with Neil DeGrasse Tyson and he said something that got my wheels turning. Our DNA is only 1% different from our closest cousins, the chimpanzee, and look what that 1% can do as far as intelligence. The smartest ape may be able to stack some boxes to get a banana and do some rudimentary sign language, but they are no more intelligent than a toddler (as far as our definition). It is pretty audacious to believe that we will run into aliens who are exactly the same as us genetically. Even if they have DNA as their molecular code for life, they will probably be more or less than 1% different from us. We can't even communicate with another species on the planet, so what makes us believe we will be able to communicate with an intelligent life form? And what about intelligence? What if to them, we are like the chimps and their toddlers are doing algebra and writing term papers in school and then grow up to be "genius" to a degree we cannot fathom? He even goes on to say that we stick chimps in zoos for our entertainment, so would they do the same to us?
My argument is, evolution works by natural selection to increase fitness - fitness as defined by a population being able to breed and pass on their genes. Therefore, we became more intelligent over time as a means to problem solve to survive - find food, compete with other species, communicate, etc. I do not see why we would see a significant growth in intelligence past the point we are at now. Evolution has no need to make us more intelligent because we have conquered the planet. There is no more selection pressure for our population to be smarter. The same goes for another species on another planet, unless their is some niche I just cannot think of that would require ever-increasing smartness. Hmm...
So, I do not believe that if we run into another alien species they will be vastly different from us intellectually. In other ways, yes, of course. The aliens in my book are humanoid because it is well known that the human hand is the greatest tool of all time. In order for another intelligent species to build ships to even get here, they would need something similar. Now if we go to another planet there could very well be an intelligent species that looks completely different physically - but they won't be making the tools they need to go anywhere, knows what I'm sayin'?
Thanks Mr. Tyson for making me think!