 The theological developments in the nineteenth century in reference to which the term “fideism” was first used had their philosophical inspiration not simply in the skepticism of the sixteenth and seventeenth centuries, however, but also, and more immediately, in Immanuel Kant’s critical philosophy. For Kant, God’s existence was a postulate of practical – rather than pure – reason. Accordingly, Kant rejected the traditional “proofs” of God’s existence – the cosmological, teleological, and ontological arguments – in favor of a moral argument. Thus, although Kant famously championed the conception of a thoroughly “rational” (i.e., moral) version of Christianity – a “religion within the limits of reason alone” – he also placed religious belief outside the domain of what can be known by means of speculative philosophy. In this way, he “found it necessary to deny knowledge, in order to make room for faith” (1929, 29).