Here's one of those lists that are fun to argue about: What are the 25 most important innovations in human history? No. 1 is hard to argue with:
spoken language -- true semantic, syntactic, phonetic language. This idea allowed humans to transmit information about the world from one person to another. It underlies all cooperation, the economy, and clan relationships. Spoken language is the most important innovation we have ever come up with.
He also adds an Innovation Zero, intentional teaching, "the idea that humans can intentionally transmit culture and generalize knowledge from the specific instance to that which is teachable, and then intentionally give that knowledge to another person across time and space. From telling your child that the fire is hot and not to touch it to the internet itself, intentional teaching is the most important innovation of all time." But that's not so much an innovation as a part of the human condition.
At first glance, I'd probably put moveable type and paper a lot higher on the list (but perhaps I'm prejudiced), and I'd move law a little higher. I'd move farming from No. 7 somewhere into the top five, perhaps even at No. 2 or 3.
