  We provide a formal definition of blameworthiness in settings where multiple
agents can collaborate to avoid a negative outcome. We first provide a method
for ascribing blameworthiness to groups relative to an epistemic state (a
distribution over causal models that describe how the outcome might arise). We
then show how we can go from an ascription of blameworthiness for groups to an
ascription of blameworthiness for individuals using a standard notion from
cooperative game theory, the Shapley value. We believe that getting a good
notion of blameworthiness in a group setting will be critical for designing
autonomous agents that behave in a moral manner.
