Task: Text Categorization
Input (English): One of this thinker's works claims "Subjectivity is truth" and is seen as a sequel to a work that defines man as the "Learner" and his "Error" as sin. This author of Concluding Unscientific Postscript to Philosophical Fragments included the "Seducer's Diary" in another work that discusses the evolution through the aesthetic, ethical, and religious stages of life. He asked, "Is there a teleological suspension of the ethical" in a work that contrasts the knight of infinite faith with the knight of infinite resignation. That work examines Abraham's sacrifice of Isaac. For 10 points, name this author of Either/Or and Fear and Trembling, a frequent user of pseudonyms.
Output (English): Social Science