Evaluating the truth of an argument primarily involves deciding if the evidence fits the claim and if the evidence is enough to believe the claim. We examine the evidence presented and see if it meets up with our standards of good evidence, just as a judge and jury weigh the evidence in a trial to see if it is enough to convict.
Poor arguments fall into patterns called fallacies. Noticing such a pattern can alert you quickly to the fact that the argument is going nowhere. However, the study of fallacies is limited because there are many ways arguments can go wrong. All of these ways are variations of one problem: They have failed to present appropriate and convincing evidence. Instead they appeal to people in various other ways.
An excellent website that catalogs and explains a wide variety of false appeals is called Mission: Critical. It gives lots of helpful examples of how arguments go wrong. Below are just a few tactics to watch out for.
Bandwagon. Bandwagon arguments say that you should do something because everyone else is doing (i.e., you should "get on the bandwagon"). Sometimes the bandwagon appears as the modern way, and doing things differently would "turn back the clock." It could be that what everyone is doing is harmful or foolish, and you are better advised to stay off the bandwagon.
Begging the question. Begging the question means assuming a claim that is in question. This evades the question of whether or not the claim is true. One of the most common ways to beg the question is to attack the character of an opponent rather than presenting evidence for a claim: Name calling.
Name calling. Name calling is attacking a person's character instead of addressing his claims. It is such a mainstay in Internet discussions that it has a special name: flaming. Flames are hurtful insults designed to drive away an opponent rather than providing a reasonable answer.
False cause. False-cause arguments make unjustified claims about the causes of behavior. This happens frequently in evaluating empirical claims in the social sciences. With the best of intentions, people provide correlational evidence to argue about a cause. A correlation simply means that two kinds of behavior are found together. For example, we know children who voluntarily read a lot score better on reading achievement tests. Can we conclude that we can raise reading scores by getting children to read more? The correlation between voluntary reading and achievement is not enough to support this claim. It may be that children read more because they are good readers. Another type of false-cause argument generalizes from a single case study. With a single case, it is impossible to know what caused a behavior because there are no experimental controls to rule out other explanations. Using careful standards for evaluating scientific research can help us rule out false-cause arguments.
Slippery slope. Slippery slope arguments exaggerate the consequences of a course of action. For example, the popular writer Rudolph Flesch, after identifying some less effective teaching strategies for helping children learn to read, argued that future generations would have to import doctors, lawyers, and scientists because no one who had learned to read in our schools would be capable of the serious reading required by these professions. Needless to say, this hasn't happened. Slippery slope arguments fail to take into account the corrective forces that counter adverse events.
Return to "How do you know if a claim is true?"
to the quotations from Nothing But the Truth.