This chapter presents some important, mostly recent, writers who are developing naturalist spirituality. Recently, Mario De Caro and David Macarthur have published two collections of technical philosophical essays, Naturalism in Question and Naturalism and Normativity. In the "Introduction" to the former, the editors state that what they call "scientific naturalism" is the current orthodoxy in Anglo-American philosophy. Liberal naturalism challenges scientific naturalism in part by questioning the latter's consistency. The chapter presents some theories as examples of writers who have developed theories of spirituality within a naturalistic framework. For George Santayana, in Reason in Religion, religion is an imaginative symbol for the Life of Reason. Spirituality is the higher side of religion, which imposes a direction and ideal on the forces of human life, in short, an aspiration. Owen Flanagan's discussion of spirituality appears in his book, The Really Hard Problem, particularly Chapter 6, "Spirituality Naturalized".