Focusing on Michael Hißmann’s Psychologische Versuche (1777), this chapter documents the role granted to experience by representatives of ‘Göttingen materialism,’ an underinvestigated movement that emerged from the anti-Wolffian, Lockean ideas defended by Meiners and, to a lesser extent, Feder. In particular, Wunderlich shows how Hißmann moved beyond Meiners’s empiricist manifesto Revision of Philosophy (1772) by arguing that philosophical investigations into the soul should be based not so much on inner experience as on the “key observations of the medical doctors,” that is, on findings obtained in physiology and medicine. Wunderlich contends, moreover, that while Hißmann took his materialism to be an anti-metaphysical endeavor, he held that we can neither prove nor disprove the possibility of immaterial beings by drawing on these sciences. In this regard, he argues, Hißmann’s materialism does not exclude a Leibnizian account of the soul. The chapter concludes by discussing Hißmann’s mitigated appreciation of Leibniz’s monadology as at least a consistent hypothesis.