Roland Wittwer is head of research of the Galen-project (formerly Corpus Medicorum Graecorum) at the Berlin-Brandenburg Academy of sciences. His research interests cover all aspects of ancient medicine, ancient philosophy and textual criticism with a focus at present on Galen and Hellenistic philosophy. Within the context of Topoi he is currently working on a new edition of Philodemus De signis (PHerc 1065), a key text on ancient theories of sign-inference. He is the spokesman of the research group (D-2) Mapping Body and Soul .