Emotion's role in human behavior is an old debate that has become increasingly relevant to the computational sciences. Two-and-a-half millennia ago, Aristotle espoused a view of emotion at times remarkably similar to modern psychological theories, arguing that emotions (such as anger), in moderation, play a useful role, especially in interactions with others. Those who express anger at appropriate times are praiseworthy, while those lacking in anger at appropriate times are treated as a fool. The Stoics took a different view; four centuries after Aristotle, Seneca considered emotions (such as anger) as a threat to reason, arguing, "reason ... is only powerful so long as it remains isolated from emotions." In the 18th century, David Hume radically departed from the Stoic perspective, arguing for the key motivating role of emotions, saying, "Reason is, and ought only to be the slave of the passions."
A similar dichotomy of views can be seen in the history of artificial intelligence (AI) and agent research. Early work by Herbert A. Simon35 argued that emotions served a critical function in intelligent behavior, as an interrupt capacity that provides a means for an organism to shift between competing goals, as well as to balance reactive and deliberative processing. Marvin Minsky posed his question of whether a robot could even be intelligent without emotion. However, late-20th century AI research took a more Stoic perspective, treating emotion as antithetical to intelligence.