How we think about ourselves can determine how we think about God, and how we think about God can affect our self-understanding. Virtually all the major world religions insist upon the cardinal importance for all of us to know ourselves. Ernst Cassirer went so far as to characterize the duty to “know thyself” in Judaism, Buddhism, Confucianism, and Christianity as a categorical or absolute imperative. The vital importance of knowing oneself is an especially central theme in Christian spiritual texts, poetry, theology, and philosophy. Christian mystics, such as Meister Eckhart, have held that self-knowledge is crucial to spiritual development; it is in some sense prior to knowledge of God. Well before him, Augustine interwove self-exploration and strenuous philosophical reflection on the mind of God in the Confessions. For Augustine, the pursuit of self-knowledge and the knowledge of God occur together naturally and virtually simultaneously. In his classic work On the Trinity, Augustine even proposed that our internal, mental life of memory, intellect, and will could be recognized as a mirror, vestige or distant reflection of the inner, three-part life of God. Our interior life is an echo of God's.

Today many philosophers would endorse something like Augustine's and Eckhart's insistence upon the link between our view of God and our view of the self, but conclude that deep philosophical reflection on what it is to be a person, to act intentionally and to have conscious experience, undermines any substantive view of God and, indeed, of religion as a whole.