Discussion of "Causal inference using invariant prediction:   identification and confidence intervals" by Peters, B\"uhlmann and   Meinshausen
  Contribution to the discussion of the paper "Causal inference using invariant prediction: identification and confidence intervals" by Peters, B\"uhlmann and Meinshausen, to appear in the Journal of the Royal Statistical Society, Series B. 
Chris J. Oates, Jessica Kasza and Sach Mukherjee
stat.ME