First, like all life-forms, we survive because we extract energy from our environment and turn that energy into more of ourselves. Second, like all the more intelligent animals, we are curious creatures. We are constantly tinkering, wondering whether things are edible, whether we can have fun with them, whether we can improve them. We are just much better at tinkering than other animals, because we have big, fast brains with lots of folds to think things through, endlessly supple vocal cords to talk things through, and opposable thumbs to work things through.
