Yet Galen seems remarkably confident about the possibility of secure knowledge, even in areas where he is able to produce little that looks like a “demonstration”: to the above case of element theory we might add, for example, the confident classification of pathological states and their signs or, indeed, the quantificatory account of drugs and their dosages in the pharmacological work. In all such cases, Galen seems convinced, a method proceeding from reliable empirical starting-points and applying sound logical method (and where relevant training the perceptual senses) may lead to secure knowledge; see van der Eijk 2015; Singer 2021b.