The Austrian philosopher Ludwig Wittgenstein (1889-1951) is often considered to be the most influential philosopher of the twentieth century. As the quotation above suggests, Wittgenstein was himself greatly influenced by the thinker he considered the most profound thinker of the previous century, Søren Kierkegaard. As scholars have recently demonstrated, Wittgenstein’s work, including his early Tractatus Logico-Philosophicus, published in 1922, and later Philosophical Investigations, posthumously published in 1953, was greatly inspired by his encounter with Kierkegaard’s thinking. Kierkegaard also profoundly influenced the transition in Wittgenstein’s thought between this early and later work, as we can see in the 193037 Denkbewegungen (“Movements of Thought”) notebooks only recently published in 1997 and in his 1938 “Lectures on Religious Belief.”