I’m a number cruncher. Always have been, always will be. If you’ve read any of my blog posts about running or bicycling, you know this. That doesn’t mean I believe numbers are everything, because they’re not and I don’t; but they’re something. By analyzing my performance over time, under similar conditions, I gain a better understanding of my progress toward goals and of the effect aging has on such things as heart rate and speed. Here is a review of a new book by Yale law professor Ian Ayres.