What ethics can learn from experimental economics - if anything

Relying on the specific example of ultimatum bargaining experiments this paper explores the possible role of empirical knowledge of behavioural norm(ative) facts" within the search for an inter-personal (W)RE - (Wide) Reflective Equilibrium on normative issues. Assuming that pro-social behaviour reveals" ethical orientations, it is argued that these norm-facts" can and should be used along with stated preferences in justificatory arguments of normative ethics and economics of the means to given ends" variety.