  Artificial intelligence (AI) is supposed to help us make better choices. Some
of these choices are small, like what route to take to work, or what music to
listen to. Others are big, like what treatment to administer for a disease or
how long to sentence someone for a crime. If AI can assist with these big
decisions, we might think it can also help with hard choices, cases where
alternatives are neither better, worse nor equal but on a par. The aim of this
paper, however, is to show that this view is mistaken: the fact of parity shows
that there are hard limits on AI in decision making and choices that AI cannot,
and should not, resolve.
