What is the theme in The Metaphysical Club: A Story of Ideas in America by Louis Menand?

Science and Religion make up the major theme. During the 19th Century, religion was the basis for everything. Harvard College started as a religiously based school and all the curriculum was focused around religion. However, as science began to grow and become more complex, religion started being pushed to the side. Those in philosophy wanted to show science and religion could be integrated without damaging the dogma or findings of the two fields of study.