In ethics

Ethics

Ethics, also known as moral philosophy, is a branch of philosophy that addresses questions about morality—that is, concepts such as good and evil, right and wrong, virtue and vice, justice and crime, etc.Major branches of ethics include:...

, the plank of Carneades is a thought experiment

Thought experiment

A thought experiment or Gedankenexperiment considers some hypothesis, theory, or principle for the purpose of thinking through its consequences...

 first proposed by Carneades

Carneades

Carneades was an Academic skeptic born in Cyrene. By the year 159 BC, he had started to refute all previous dogmatic doctrines, especially Stoicism, and even the Epicureans whom previous skeptics had spared. As head of the Academy, he was one of three philosophers sent to Rome in 155 BC where his...

 of Cyrene

Cyrene, Libya

Cyrene was an ancient Greek colony and then a Roman city in present-day Shahhat, Libya, the oldest and most important of the five Greek cities in the region. It gave eastern Libya the classical name Cyrenaica that it has retained to modern times.Cyrene lies in a lush valley in the Jebel Akhdar...

; it explores the concept of self-defense

Self-defense

Self-defense, self-defence or private defense is a countermeasure that involves defending oneself, one's property or the well-being of another from physical harm. The use of the right of self-defense as a legal justification for the use of force in times of danger is available in many...

 in relation to murder

Murder

Murder is the unlawful killing, with malice aforethought, of another human being, and generally this state of mind distinguishes murder from other forms of unlawful homicide...

.

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, proximately, 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.

The Case of the Speluncean Explorers

The Case of the Speluncean Explorers

The Case of the Speluncean Explorers is a famous hypothetical legal case used in the study of law, which was written by Lon Fuller in 1949 for the Harvard Law Review....

 by legal philosopher Lon Fuller is a similar exploration of morality and legality in extremis.

See also

• Duress
  Duress
  In jurisprudence, duress or coercion refers to a situation whereby a person performs an act as a result of violence, threat or other pressure against the person. Black's Law Dictionary defines duress as "any unlawful threat or coercion used... to induce another to act [or not act] in a manner...
  
  
• Trolley problem
  Trolley problem
  The trolley problem is a thought experiment in ethics, first introduced by Philippa Foot, but also extensively analysed by Judith Jarvis Thomson, Peter Unger, and Frances Kamm...
  
  
• Deontology
• Utilitarianism
  Utilitarianism
  Utilitarianism is an ethical theory holding that the proper course of action is the one that maximizes the overall "happiness", by whatever means necessary. It is thus a form of consequentialism, meaning that the moral worth of an action is determined only by its resulting outcome, and that one can...