What we learn from this book is not only that Facebook friends cannot replace real, authentic, bodily friendships with a real community, but also that humans do in fact need community. No person is biologically designed to be alone, because we are animals that herd, so even the most introverted introverts are introverted compared to the social tendencies of a herd. Overall, however, every human is evolved to be in communities of up to 150 friends and family members.
These kinds of differences between perception and reality are why the book is playfully titled You Are Not So Smart. It's a joking reminder that if we study our brains from a scientific perspective, we can discover that we are not designed for mathematical precision. In other words, every human is limited by animal nature, literally, because we are literally animals.
Why should humans need a reminder that we are animals? Because the experience of having a mind doesn't necessarily imply that a person will question the truth of their own point of view. Many people go through life with a delusional sense of confidence about their conclusions and opinions. By paying closer attention to the various ways we are limited, we can begin to approach life with more strategy and honesty.
