Social life consists of making mistakes, then correcting them. The big questions do not concern who makes the fewest mistakes and why, but whether the mistakes are fruitful, how fast people recognize them, and how well they correct them. The same principles apply to writing books, even if the interaction and error-correction take longer to operate than in everyday conversation. This symposium's vigorous, vital critiques of Durable Inequality establish that my book is no exception to the rule. Clearly in writing the book I made mistakes of at least four kinds: