 Although technically Boas' doctorate degree was in physics, his advisor Fischer, a student of Carl Ritter, was primarily a geographer and thus some biographers view Boas as more of a geographer than a physicist at this stage.The combination of physics and geography also may have been accomplished through a major in physics and a minor in geography.For his part Boas self-identified as a geographer by this time, prompting his sister, Toni, to write in 1883 "After long years of infidelity, my brother was re-conquered by geography, the first love of his boyhood."