And a quote explaining the main theme of the book:
Yet, as Dennett and others argue, genetic evolution is not enough to explain the skills, power and versatility of the human mind. Over the past 10,000 years, human behaviour and our ability to manipulate the planet have changed too quickly for biological evolution to have been the driving force. In Dennett’s view, our brains turned into fully fledged modern minds thanks to cultural memes: ‘ways of behaving’ — pronouncing a word this way, dancing like so — that can be copied, remembered and passed on.
Some memes are better than others at getting passed on. This drives natural selection, fashioning memetic design without a designer. The first memes, Dennett argues, were words, “the lifeblood of cultural evolution”, which act as virtual DNA for the richly cumulative cultural evolution that marks out our species. At first, he writes, words evolved to better fit the brains they had to colonize. Only later did brains start evolving genetically to better accommodate words, beginning a co-evolutionary process that turned us into voluble creatures.