This worksheet focuses on a defining piece of 20th Century ethics. It is so well-known that it has made its way into popular culture — a rare feat for philosophy! It concerns the well-known “Trolley Problem”, and was devised by Philippa Foot. Moreover, the problem is usually employed to convey and discuss the basics of consequentialist ethics. However, the use that Foot makes of the problem is far more subtle and well worth considering: the doctrine of double effect.