The Ottoman reformist intellectuals’ strong association of materialist and positivist currents in the West with modernization itself has been a central feature of the studies on the intellectual history of the late Empire. The reaction which the scientific materialism espoused by these thinkers engendered on the part of the Ottoman proponents of philosophical spiritualism has also been given considerable scholarly attention. Yet another heated debate, almost completely ignored by historians and intricately linked to the one just mentioned, had briefly flared up in fin de siècle Istanbul between the practitioners of phenomenal spiritualism and certain members of the capital’s medical community about the possibility of communicating with the dead. The episode in question not only complicates the current picture of the intellectual history of the period, but also carries considerable significance for the study of the history of Ottoman science. This talk focuses on the controversy precipitated by the appearance, after 1908, of a number of periodicals and books in Turkish that were dedicated to modern occultism in general and spirit communication in particular. As “table-turning” quickly turned into a fad in an Istanbul where the so-called Young Turk Revolution had just taken place, some of the claims made by these publications were publicly denounced by two prominent doctors: Kemal Cenab [Berksoy] (1876-1949), a professor of physiology at the University of Istanbul, and the psychiatrist Mazhar Osman [Usman] (1884-1951). Based both on the contents of the Ottoman spiritualist publications, and on the reactions of Kemal Cenab and Mazhar Osman, it will be argued that the question of scientific authority lay at the center of this controversy. While being of interest to anti-materialist circles in the capital, the doctrines embraced by the Ottoman spiritualists notably claimed a great degree of scientificity and empirical validity. In this context, it will be emphasized that the emergence of a short-lived but vibrant Ottoman spiritualist press coincided with a growing emphasis on psychical studies in the West and a positivist approach to the detection of spiritual phenomena.