In his book, The Logic of Religious Experience, Leidhold focuses on spiritual experience. He systematically analyzes it, looking at it from an intercultural and historical perspective. By applying his theory of experience to religion and its spiritual foundations, he shows how spiritual experience has evolved in the course of history and throughout an array of Eastern and Western cultures. This examination reveals that the way people get in touch with the numinous. The structure of spiritual experience, has changed several times. Elements of its structure were only gradually brought to light.
He defines spiritual experience as participation in a peculiar source, the so-called numinous. The peculiarity of this numinous source is that the source itself becomes not present as an object, but is realized only as a genuine form of participation. Spiritual experience is the participation in something transcendent, i.e. the awareness of an absent presence. Later he discusses this paradoxical experience in more detail, demonstrating its rationale or ‘logic’, as implied by the work’s title.
He addresses deformed varieties of religious experience. He states: If of the two components of religious experience (the absent presence) only the moment of absence remains, then this leads to nihilism or to a theology without participation in transcendence. If, on the other hand, only the moment of presence is represented, it leads to some sort of reified deity, deifying all kinds of things (the universe as a whole ((pantheism)), parts of it (((such as celestial bodies, the earth etc.))), even humanity itself, the nation or the “race.”) In the end, he looks at this through the lens of major religious traditions (Hinduism, Zarathustra, Judaism, Christianity, Greek and Roman antiquity, Taoism, and Islam).
In dealing with the history of religious experience, several questions arose. Did all dimensions of experience develop along a similar trajectory? Did they all originate at the same time, like on an axis? Or was there a sequence, so that first one, then another had emerged? Was there a kind of genealogy of experience? These questions appeared to Leidhold to be worthy of further investigation. The result was a project of a comprehensive history of experience.