He offered sharp criticisms of Immanuel Kant's approach to epistemology.
[4] In his article "The Conquest of Subjectivism,"[5] Paul Ferdinand Linke pointed out that it was Rehmke who first made a courageous break from subjectivism, which was the pervasive philosophical paradigm in late modern German philosophy.
After his first lessons from his father, he attended the elementary school in Uetersen and then the Gymnasium Christianeum in Altona, where among others Helmuth von Moltke was his classmate.
Rehmke earned his doctorate in 1873 at Zurich with the thesis Hartmanns Unbewußtes auf die Logik hin kritisch beleuchtet (Hartmann's Unconscious Critically Examined from a Logical Standpoint; a work on Karl Robert Eduard von Hartmann) and his habilitation in 1884 at the University of Berlin with his 1880 monograph Die Welt als Wahrnehmung und Begriff (The World as Percept and Concept).
In 1921, Rehmke was forced by local Nazi-groups[citation needed] (among them student organisations) to give up his professorship at Greifswald.