Logical fallacies are errors of reason that can occur in inductive reasoning. Since inductive reasoning moves from the particular to the general, it is important to determine how much and what kind of evidence you need to make a valid argument. Failure to have proper evidence is linked to several kinds of logical fallacies.
Since logic is one of the main techniques used in persuasion, being able to identify and discount logical fallacies in others' arguments and avoid making them in one's own arguments are both important. One of the things that can undermine logic is resting arguments on an appeal to emotion, rather than arguing on rational grounds. There are several errors that one can make through an appeal to emotion, and the following fallacies of appeal to emotion occur so frequently that they are named.
Appeal to hate. This fallacy connects the quality of an idea to its general appeal. An example is: The hard-working families of this city are adamantly opposed to this change in the high school graduation requirements enacted, and that proves that it's a bad idea. This is a logical fallacy of appeal to emotion because the quality of a suggestion cannot be determined from the emotional response of people who support it or reject it, but resides in the details of the idea itself.
Appeal to force. Using threat or force to persuade a course of action is an appeal to force. It is another example of a way to involve emotions rather than reason in a decision. An example is: If you don't support my candidacy for mayor, you'll be sorry, believe you me . . . The fear of dire consequences to one's person is not the kind of influence that should determine political decisions -- it is an appeal to emotion to force a decision, rather than an appeal to reason to make a logical decision.
Guilt by association. In this fallacy, there is an assumption that a connection furnishes more information than it actually does. An example is: The chairperson was in office during the purchase of that hideous new oil painting, so of course, we can't trust her judgment . . . This fallacy may fail either by drawing the erroneous conclusion that because two things are connected in one regard, they are connected in every regard, or alternatively, that anyone with any connection to certain items or people must be beyond the pale.
In the above example, holding an office during an event does not necessarily identify that person as supporting or responsible for the event. For all we know, the chairperson might have voted against the purchase and been overruled by others. Knowing as little as we do, it is certainly not valid to draw general conclusions about her judgment. By trying to engage our wrath about a previous decision, the argument is an appeal to emotion and tries to involve our emotions about the earlier decision in the current discussion. This is not a rational way to make a decision.
