Delusion as error: the history of a metaphor.

Error has been the major metaphor for understanding delusions through the past three centuries. Modern definition of delusion as erroneous opinion or belief is evidence of the continuing role of this metaphor to this day. However, through long habituation the metaphorical nature of the association between delusion and error is no longer recognized. In other words, the metaphor has become literal and all but invisible. This paper seeks to shed light on this metaphor by tracing its development from inception in the seventeenth century to the present time. Also, the impact of the metaphor on modern research and therapeutic approaches is briefly discussed. Finally, to put the metaphor of error in perspective, some other metaphors applied to delusion over the years are reviewed.