The compatibility of science and religion is the main theme of the book.Numerous essays in God in the Dock try to show that science and religion are compatible. Specifically, many believe that modern science renders belief in Christianity irrational, but Lewis denies this. In "Miracles" he argues that modern science does not teach that miracles are impossible; at best, it shows that they are rare. In "Dogma and the Universe" Lewis maintains that there is no problem holding to Christian dogma in a world where science is always developing.