Plank of Carneades

In ethics, the plank of Carneades is a thought experiment first proposed by Carneades of Cyrene; it explores the concept of self-defense in relation to murder.

In the thought experiment, there are two shipwrecked sailors, A and B. They both see a plank that can only support one of them and both of them swim towards it. Sailor A gets to the plank first. Sailor B, who is going to drown, pushes A off and away from the plank and, thus, ultimately, causes A to drown. Sailor B gets on the plank and is later saved by a rescue team. The thought experiment poses the question of whether Sailor B can be tried for murder because if B had to kill A in order to live, then it would arguably be in self-defense.

Plank of Carneades in fiction

*In the "Kindaichi Case Files" manga volume 6, The Legend of Lake Hiren, the target of the murderer was in a situation involving Carneades' Plank.
*In the 2003 movie "Saw", Doctor Gordon must kill Adam Faulkner in order to be released from a remote room. This situation could be argued as involving Carneades' Plank.
*In the anime "Gunbuster", Operation Carneades refers to a military exercise to destroy a large portion of the galactic core to insure mankind's survival at the expense of an alien menace.

Plank of Carneades in reality

*The English case of "R. v. Dudley and Stephens" (1884) established that necessity is no defence against a charge of murder.

ee also

*Duress
*Trolley problem