The article shows the “Appendix” to Søren Kierkegaard’s Philosophical Fragments to be a response to Ludwig Feuerbach’s critique of Christianity. While previous studies have detected some influence by Feuerbach on Kierkegaard, they have so far discovered little in the way of specific responses to Feuerbach’s ideas in Kierkegaard’s published works. The article first makes the historical argument that Kierkegaard was very likely reading Feuerbach’s Essence of Christianity while he was writing Philosophical Fragments, as several of Kierkegaard’s journal entries from that (...) period discuss Feuerbach in relation to central ideas in Fragments. The article then shows how Kierkegaard’s pseudonym Johannes Climacus inverts Feuerbach’s projection theory, turning it against critics like Feuerbach. At the heart of Feuerbach’s critique of Christianity is the claim that religion is a conceptual illusion, whereby the individual projects his or her personal limits onto the species and then projects the unlimited onto a supposed divine being. Furthermore, Feuerbach sees Christianity as rife with absurdities that tell against its reasonableness. In exploring a hypothetical transcendent avenue toward the truth, Climacus inverts both of these philosophical moves. He argues that on the transcendent hypothesis, the immanentist critic is himself a victim of an “acoustical illusion”: the absolute paradox of the appearance of the god in time is in fact not judged by, but rather judges, the critic as absurd. In inverting and not repudiating Feuerbach’s critique, Climacus reveals the critic as a Socratic figure who displays the heights—and ultimately, the limits—of secular philosophy’s capabilities. (shrink)