 Clinical trials are commonly anticipated by a formalized process in which participants receive explanations of the purpose, methods, risks, benefits, and alternatives to study participation, as well as other matters, before they sign informed consent forms (Beauchamp and Childress 2008, 129). Fairly similar processes exist in invasive care. But what is the point of these processes? One of Plato’s characters mocks doctors who set aside time to keep sick patients informed: “Foolish fellow, … you are not healing the sick man, but you are educating him; and he does not want to be made a doctor, but to get well” (Plato Laws, IV.720a–c, p. 413). Let us discuss two forms of transgression of the information requirement: (1) lies, deceit, and merely-partial disclosure, and (2) the patient’s failure to comprehend well-presented information. We shall then discuss (3) the content and (4) the cogency of the information requirement.