by Timothy Lane
Being Logical (Random House, 2004) by D. Q. McInerney, at the time a professor of logic and philosophy, is a general guide to logical reasoning and civil discourse. The author studies how to avoid bad arguments, for example by listening (or reading) carefully to what someone else is saying and getting the facts straight (the first of 10 general rules in the first part, which covers “preparing the mind for logic”). The second part looks at basic principles, dealing with subjects such as generalizations and categorical statements, the importance of defining terms, and analyzing causes that lead to events.
In part 3 the author gets into the language of logic. This includes the making of syllogisms and using conditional arguments. This section includes a lot of difficult language for the layman, but it also gives basic guidelines for how to use formal logic.
A good recent example of flawed logic can be seen in Elizabeth Warren’s argument that she considered herself an Indian because of a picture of her “mamaw” (having grown up with frequent visits to relatives in rural Kentucky, I must say it’s nice hearing such usages from a Massachusetts senator) showing her high cheekbones. According to Warren’s grandfather, all Indians had high cheekbones, and so Warren’s grandmother and mother (though by her own admission, not Warren herself). It shouldn’t have taken any knowledge of formal logic to realize that if all Indians have high cheekbones, Warren (who doesn’t) isn’t an Indian (and thus shouldn’t have claimed to be one in seeking college employment).
But the argument never made sense to begin with. Formed into a syllogism, we would have, “If a person is an Indian, that person has high cheekbones.” If we know that a person really is an Indian, then we could predict that the person has high cheekbones. If we know that a person doesn’t have high cheekbones, then we could conclude that the person isn’t an Indian. But if a person has high cheekbones, who knows? There could be some other explanation.
Part 4 covers “sources of illogical thinking.” Mostly these are attitudes such as skepticism or cynicism that have their place but can be taken too far. The author also covers “evasive agnosticism,” narrow-mindedness, and emotional disputation. A good rational, civil argument isn’t a quarrel; when emotional commitments come in, that changes. All told, the author lists 9 different sources of illogic.
The last part lists 28 logical fallacies (which people who’ve read enough of my blogs elsewhere may have encountered on occasion). Some of these deal with errors in formal logic, and others deal with well-known fallacies such as begging the question (fallacy 5), the straw man argument (fallacy 7), the ad hominem argument (fallacy 11), the red herring (fallacy 19), and special pleading (fallacy 25).
In addition, there are such fallacies as “laughter as diversionary tactic” (fallacy 20), which I suspect most active bloggers will have encountered numerous times. Some are given as guides, such as “consider more than the source” (fallacy 15). This last fallacy includes the “argument from authority,” but also the reflexive rejection of a known poor source. Thus, if one considers Barack Obama a pathological liar (as I do), then one is entitled to be skeptical of what he says, but such justified mistrust doesn’t actually disprove his argument.