I voted for Intelligence and Survival of the Fittest. I mean, we would have no technology if we were not intelligent, eh? I mean, if we were not evolved to be intelligent and efffect our suuroundings, we would still be apes hanging from trees scratching our armpits.
However, this is not the answer. The true basis of our society is 42. It is the ultimate answer to everything. Read Hitchhikers Guide to the Galaxy for more info. The ultimate question, however, is a mystery.