There has been contention in recent debates concerning what constitutes acceptable forms of argument when dealing with emotive issues, and the purpose of this article is to offer some simple guidelines that may provide assistance in this regard.
 

Fallacies

Carl Sagan in his book The Demon-Haunted World (page 199-200) offers a list of some common fallacies that are often found in arguments. I present it here for our reader's consideration so that they can avoid falling into errors of reasoning:

"· Argument from authority (e.g., President Richard Nixon should be re-elected because he has a secret plan to end the war in Southeast Asia – but because it was secret, there was no way for the electorate to evaluate it on its merits; the argument amounted to trusting him because he was President: a mistake, as it turned out).

· Argument from adverse consequences (e.g., a God meting out punishment and reward must exist, because if He didn't, society would be much more lawless and dangerous – perhaps even ungovernable. Or: the defendant in a widely publicized murder trial must be found guilty; otherwise, it will be an encouragement for other men to murder their wives).

· Appeal to ignorance - the claim that whatever has not been proved false must be true, and vice versa (e.g., there is no compelling evidence that UFOs are not visiting the Earth; therefore UFOs exist - and there is intelligent life elsewhere in the Universe. Or: there may be seventy kazillion other worlds, but not one is known to have the moral advancement of Earth, so we're still central to the Universe). This impatience with ambiguity can be criticized in the phrase: absence of evidence is not evidence of absence.

· Special pleading, often to rescue a proposition in deep rhetorical trouble (e.g., how can a merciful God condemn future generations to unending torment because, against orders, one woman induced one man to eat an apple? Special plead: you don't understand the subtle Doctrine of Free Will. Or: how can there be an equally godlike Father, Son and Holy Ghost in the same Person? Special plead: you don't understand the Divine Mystery of the Trinity. Or: how could God permit the followers of Judaism, Christianity and Islam - each in their own way enjoined to heroic measures of loving-kindness and compassion - to have perpetrated so much cruelty for so long? Special plead: you don't understand Free Will again. And anyway, God moves in mysterious ways).

· Begging the question, also called assuming the answer (e.g., we must institute the death penalty to discourage violent crime. But does the violent crime rate in fact fall when the death penalty is imposed? Or: the stock market fell yesterday because of a technical adjustment and profit taking by investors. But is there any independent evidence for the causal role of 'adjustment' and profit taking; have we learned anything at all from this purported explanation?).

· Observational selection, also called the enumeration of favorable circumstances, or as the philosopher Francis Bacon described it, counting the hits and forgetting the misses (e.g., a state boasts of the Presidents it has produced, but is silent on its serial killers).

· Statistics of small Numbers - a close relative of observational selection (e.g. 'they say I out of 5 people is Chinese. How is this possible? I know hundreds of people, and none of them is Chinese. Yours truly'. Or: 'I've thrown three sevens in a row. Tonight I can't lose.')"
 

Ad Hominem

An ad hominem argument is where the person espousing an argument is attacked rather than the argument itself. Robert H. Thouless, in his book Straight and Crooked Thinking, (page 170 - 176) provides a number of examples of this kind:

"· Angering an opponent in order that he may argue badly. Dealt with by refusing to get angry however annoying our opponent may be...

· Argument by attributing prejudices or motives to one's opponent. Best dealt with by pointing out that other prejudices may equally well determine the opposite view, and that, in any case, the question of why a person holds an opinion is an entirely different question from that of whether the opinion is or is not true."

It is important to remember that questioning the worth of an individual's beliefs is very different from questioning the worth of an individual. For example, consider the following statements:

(1)    X's arguments are deficient because of y.
(2)    X is deficient because of y.