I've been reading blogs like Less Wrong for almost a decade. So then, a lot of what was said in this book wasn't new to me. However, I still really liked it.
I'm of the opinion that in order to deeply understand a topic, it's not just enough to understand it conceptually, you have to see lots and lots of examples of it, from many different angles. I felt like this book helped me with that. Despite the fact that I spend so much time reading rationality related blogs, The Scout Mindset still felt like it non-trivially deepened my understanding of the subject matter.
The stories that were told in this book were really good. They were a nice blend of appropriate, instructive, and engaging. I'm always impressed when books like these manage to do this. I spend too much of my time reading blogs and not enough of my time reading books. I often find myself similarly impressed by the quality of stories chosen in other books as well.
My main critique of The Scout Mindset is that, well, let me start with this. Early in the book, Julia pointed out that the difficulty isn't in knowing that you should do stuff like account for cognitive biases. It's in actually bringing yourself to do it!
My path to this book began in 2009, after I quit graduate school and threw myself into a passion project that became a new career: helping people reason out tough questions in their personal and professional lives. At first I imagined that this would involve teaching people about things like probability, logic, and cognitive biases, and showing them how those subjects applied to everyday life. But after several years of running workshops, reading studies, doing consulting, and interviewing people, I finally came to accept that knowing how to reason wasn't the cure-all I thought it was.
Knowing that you should test your assumptions doesn't automatically improve your judgement, any more than knowing you should exercise automatically improves your health. Being able to rattle off a list of biases and fallacies doesn't help you unless you're willing to acknowledge those biases and fallacies in your own thinking. The biggest lesson I learned is something that's since been corroborated by researchers, as we'll see in this book: our judgment isn't limited by knowledge nearly as much as it's limited by attitude.
So then, the question becomes, how do you actually get people to have a scout mindset? Julia's "approach has three prongs: 1) Realize that truth isn't in conflict with your other goals, 2) Learn tools that make it easier to see clearly, 3) Appreciate the emotional rewards of Scout Mindset". This is where my criticism comes in. I didn't really find that this approach was that effective. It didn't "tug on my heartstrings" enough.
To me, when I think about books that have moved me, they have told longer, deeper, more emotionally compelling stories. This often means that the book is fiction, but not always. It could be non-fiction. As an example of non-fiction, biographies come to mind. So does some long-form journalistic reporting. I think doing something like that in The Scout Mindset would have been more effective. Instead, Julia chose to use lots of smaller stories. By doing so, I think the book falls too close to "educational" on the spectrum from educational-to-inspirational.
That said, I do think that there is a place for a book that lives at that point on the spectrum. Not all books should be, say, at +8 points towards inspirational.
A related maybe-not-even-a-critique is that a book doesn't feel like the right medium for the goal of "inspire people to adopt a Scout Mindset". Something that is more social, interactive, and community-based seems like a better tool for that job. To her credit, Julia has in fact spent time tackling the problem from that angle in founding the Center for Applied Rationality, amongst other things. She also mentions various communities you can join online in the book such as the FeMRADebates or ChangeMyView subreddits, or the Effective Altruist community. And I'll mention Less Wrong again as another example.
Overall, I felt that The Scout Mindset was a pleasant read, and a book that did help me make progress as a scout. I don't feel like it was very much progress though, and I have thoughts about what could have been done instead to promote more progress. However, this is a super important topic, so any progress is valuable, and I'll happily take what I can get.