In his seminal article on philosophical authority published in 1997, David Sedley showed that, in antiquity, the founder of a philosophical school was taken as figure of ‘authority’ by subsequent members of the school, who would carefully avoid expressing disagreement with him. What is more, the reason for their deference was not purely formal, or political: the authority with which school-members invested the founder of their school was epistemic as well, in the sense that it involved some level of concern to know and be guided by their founder’s views. But this is far from the end of the story. As Jan Opsomer and Angela Ulacco have been careful to describe subsequently, ‘epistemic authority’ ranges widely in sense and strength: from uncritical assent to the truth of whatever can be gleaned from the authority-figure within a given domain, to the belief that their views might help to point one in the right direction.1 Where one stands on this question might make all the difference to the character of one’s philosophical project.