One of humanity's greatest queries has focused on the nature of a change from good to evil. There is no single answer; several possible reasons apply. Julius Caesar, who dramatically asked his friend, "Et tu, Brute?" learned the hard way about the power of opportunity. In the fictional series, Homeland, empathy for a child was the root of Nicholas Brody's turncoat actions. Finally, there is the longstanding issue of necessity, in which a person turns to crime to deal with environmental stressors, such as a lost job or poverty.