I just read William Easterly's NYTBR review of Matt Ridley's The Rational Optimist. I had to look twice to be sure of the name of the reviewer.
Yes, Ridley makes the case for optimism, but is it reasonable for a reviewer to wheel out the straw man of the unblemished "free market"? I recall the book's discussions of markets, but never an allusion to the textbook straw person. Knocking that one down is child's play and an argument easily available to anyone.
No, this is not paradise, but evidence of progress is powerful. And good things happened to humanity in the twentieth century despite two horrid world wars, the Great Depression, the Cold War, the influenza epidemic of the 1920s, etc. Ridley likes "half-full" better than "half-empty", but to mention that he forgot Lehman Bros and Richard Fuld's salary is a cheap shot.
We do not have "free markets", we have crony capitalism with way too much of "crony", but in spite of the obvious shortcomings, no informed person would trade places with his/her ancestors. That's an awesome fact and the best explanation we have is the workings of the market -- even the imperfect type.
UPDATE
Here is Ridley summarizing the book.