irrelevance

Irrelevance crops up in many arguments:

When the argument itself seems logical, yet the conclusion is not relevant to or supported by the line of argument, then the fallacy is ignoratio elenchi (ignorance of the issue). Such problems may occur when the arguer is not responding to the actual question posed.

When the line of argument is off-target for the topic under discussion and distracts from the real topic, then the arguer has tossed a red herring into debate in order to create a smokescreen.

Irrelevant attacks on the arguer or cited authority are ad hominem fallacies. However, if the "authority" who/that has been cited fails as a legitimate authority on one or more grounds, then disputing the expertise or credibility of that person/reference is not an ad hominem fallacy.

Logic and emotion are often at odds. When irrelevant appeals to emotion are incorporated into arguments, then the conclusions drawn by that argument become suspect if the emotion is not specifically related to the topic. To argue that a person will probably enjoy eating chocolate is not necessarily unfounded, though it would not be relevant to discussion about chicken pot pie.

red herrings

Red Herring, Smoke Screen, Wild Goose Chase

The red herring is a diversionary tactic that distracts the opponent away from the real point under discussion. Red herring topics are irrelevant to the point under discussion, and serve to take the heat off an already weak argument.

Because creationists and advocates of intelligent design theory are arguing for a discredited, untenable position, they must resort to debating tactics such as the red herring.