e.g. oranges have vitamin C (is); it is good to eat oranges (ought)
Moore's Open-Question Argument
argues that good couldn't be identical to any natural property because any identity claim seems to invite an "open question"
W.D. Ross - prima facie duties
keeping promises
paying back harm done to others
not injuring others
returning favours + services that others have given us
not harming innocent people
looking after parents
use where there are conflicting duties with different people's intuition pointing them in different directions - if there is a conflict, thinking carefully about the dilemma will tell us which takes priority
