Eastern philosophy
The "Dao De Jing" ("Tao-Te-Ching," c. 4th century BCE), traditionally attributed to Laozi, and the "Nan Hua Jing" ("Zhuang Zi") are considered the key texts of the tradition. The first organized form of Taoism, the Tianshi (Celestial Masters') school arose in the 2nd century CE. Xuanxue ("deep learning", also "Neo-Taoism") was a major philosophical movement influenced by Confucian scholarship, which focused on the interpretation of the "Yijing," "Daodejing," and "Zhuangzi" and which flourished during the third to sixth centuries CE. The most important philosophers of this movement were He Yan, Wang Bi, the Seven Sages of the Bamboo Grove, Ge Hong and Guo Xiang. Thinkers like He Yan and Wang Bi focused on the deep nature of Tao, which they saw as being best exemplified by the term "Wu" (nothingness, non-being, negativity).
Søren Kierkegaard
Philosophers and theologians influenced by Kierkegaard are numerous and include major twentieth century theologians and philosophers. Paul Feyerabend's epistemological anarchism in the philosophy of science was inspired by Kierkegaard's idea of subjectivity as truth. Ludwig Wittgenstein was immensely influenced and humbled by Kierkegaard, claiming that "Kierkegaard is far too deep for me, anyhow. He bewilders me without working the good effects which he would in deeper souls". Karl Popper referred to Kierkegaard as "the great reformer of Christian ethics, who exposed the official Christian morality of his day as anti-Christian and anti-humanitarian hypocrisy". Hilary Putnam admired Kierkegaard, "for his insistence on the priority of the question, 'How should I live?'". By the early 1930s, Jacques Ellul's three primary sources of inspiration were Karl Marx, Søren Kierkegaard, and Karl Barth. According to Ellul, Marx and Kierkegaard were his two greatest influences, and the only two authors of which he read all of their work.