Felony murder is a legal doctrine that holds individuals responsible for a death that occurs during the commission of a dangerous felony, even if they did not directly cause the death. This means that if someone is involved in a crime like robbery or arson and a person dies as a result, all participants in the crime can be charged with murder. The rationale behind felony murder is to deter individuals from engaging in dangerous felonies that could lead to loss of life. It emphasizes the idea that participating in a serious crime carries the risk of severe consequences, including being held accountable for unintended deaths.