  Increasingly secret, complex and inscrutable computational systems are being
used to intensify existing power relations and to create new ones; in
particular, they are being used to govern. To be all-things-considered morally
permissible new, or newly intense, power relations must meet standards of
procedural legitimacy and proper authority. This is necessary for them to
protect and realise democratic values of individual liberty, relational
equality, and collective self-determination. For governing power in particular
to be legitimate and have proper authority, it must meet a publicity
requirement: reasonably competent members of the governed community must be
able to determine that they are being governed legitimately and with proper
authority. The publicity requirement can be satisfied only if the powerful can
explain their decision-making to members of their political community. At least
some duties of explanation are therefore democratic duties. This paper first
sets out the foregoing argument, then applies it to opaque computational
systems, and clarifies precisely what kinds of explanations are necessary to
fulfil these democratic values.
