Authors unknown
"What is an emotion?" That question was asked in precisely that form by William James, as the title of an essay he wrote for *Mind* well over 100 years ago (James, 1884). But philosophers have been concerned about the nature of emotion since Socrates and the "pre-Socratics" who preceded him, and although the discipline has grown up (largely because of Socrates and his student Plato) as the pursuit of reason, the emotions have always lurked in the background—often as a threat to reason and a danger to philosophy and philosophers. One of the most enduring metaphors of reason and emotion has been the metaphor of master and slave, with the wisdom of reason firmly in control and the dangerous impulses of emotion safely suppressed, channeled, or (ideally) in harmony with reason. But the question "What is an emotion?" has proved to be as difficult to resolve as the emotions have been to master. Just when it seems that an adequate definition is in place, some new theory rears its unwelcome head and challenges our understanding.