Full Idea
The doctrine of double effect is that there is a moral distinction between what is foreseen by an agent as a likely result of an action, and what is intended.
Gist of Idea
Double effect is the distinction between what is foreseen and what is intended
Source
Thomas Mautner (Penguin Dictionary of Philosophy [1996], p.150)
Book Reference
Mautner,Thomas: 'Dictionary of Philosophy' [Penguin 1997], p.150
A Reaction
Abortion for a pregnancy threatening the mother's life. What always intrigues me is the effects which you didn't foresee because you couldn't be bothered to think about them. How much obligation do you have to try to foresee events?