He first went to Leipzig, where he attended the lectures of Moritz Wilhelm Drobisch (1802–1896), a Herbartian philosopher and one of the forerunners of the neo-Kantian revival of the 1860s. He was there at the same time that Nietzsche was a student, although it does not appear that they met. In 1869, he moved to Tübingen and to Stuttgart in 1871. Here, at the orthodox Church of the Court, he married on 30 January 1872, Elisabeth (Elise) Gatternich and the two had a daughter, Hélène. In Leipzig, Spir befriended the publisher and fellow Freemason Joseph Gabriel Findel, who published most of Spir's works. His most important book, "Denken und Wirklichkeit: Versuch einer Erneuerung der kritischen Philosophie" ("Thought and Reality: Attempt at a Renewal of Critical Philosophy") was published in 1873. A second edition, which was the one owned by Nietzsche, was published in 1877. In an attempt to reach a broader readership, Spir wrote directly in French his "Esquisses de philosophie critique" ("Outlines of critical philosophy"), published for the first time in 1877. A new edition was published forty years after his death, in 1930, with an introduction by the French philosopher and professor at the Sorbonne Léon Brunschvicg.