This chapter considers stages of growing intelligence, and even of growing spiritual knowledge, marked by an inevitable and lamentable decline in apparent depth and vitality of spiritual experience. In such stages, the greatest concerns of our lives are somehow for a while hidden, even forgotten. We become more knowing, more clever, more critical, more wary, more skeptical, but we seemingly do not grow more profound or more reverent. Such a stage in human experience is represented, in great part, by the philosophical thinkers who flourished between the time of Spinoza's death, in 1677 and the appearance of Kant's chief philosophical work, “The Critique of Pure Reason” in 1781. It is the period which has been especially associated, in historical tradition, with the eighteenth century.