In the second part entitled Constructive Watson gives such an interpretation of religious ideas as may seem to be required by the greater complexity and comprehensiveness of modern thought. Watson attends to the evolution of ideas, concentrating on suggestive ideas in Hegel and his English exponents, though refusing to accept some of the doctrines presented as Hegelian in the works of certain exponents and critics in England and Germany.

The Interpretation of Religious Experience is divided into two parts, published in separate volumes. In the first part entitled Historical Watson reflects critically upon religion and especially upon Christianity, discussing theological and philosophical writers. An enquiry into the origin and development of Christianity is conducted, devoting particular attention both to the systematic formulation of religious experience in theology and also to the influence of philosophy on theology.