The red herring fallacy is a logical fallacy in which the subject of an argument is subtly changed so that the other party or audience will completely lose sight of the original argument.
The source of the term “red herring” has been attributed to a technique of training hunting dogs in how to follow the scent of a fox during a hunt. Once the hunting dogs have found the scent of a fox, nothing will deter them from their path except for a more powerful scent. In this case, the more powerful scent comes from a smoked red herring. If the hunt, for whatever reason, needs to be called off, the “red herring” scent can be dragged along the ground in order to lead the hunting dogs in a direction other than that of the fox. This metaphor of distraction translates to the realm of argument in that it describes a method of diverting attention to a new, unrelated issue in such a manner that the listening party will completely lose sight of the original issue.
Source:
Tindale, Christopher W.. “Fallacies of Diversion.” Fallacies and argument appraisal. Cambridge: Cambridge University Press, 2007. 28. Print.