Be Reasonable – Part 3
“We’ll wrap this whole conversation up next time with some further discussion of inductive logic and the fallacies sometimes associated with it, and exactly how we should treat these rules of logic.�
OK, I have no idea what I was smoking when I wrote that last time. I could probably stretch the topics in that sentence into another three essays. Well, that just gives us fodder for the discussion, I suppose.
As I mentioned in the first article in this series, inductive reasoning differs from the deductive logic we’ve been focusing by being less formal and less absolute. Deductive logic is like a math problem. You take your inputs, you follow the procedure dictated by the operations, you get your output. Inductive reasoning is more like writing an interpretative essay for English or history class. You try and pull all your evidence together to support your conclusion, but you have to deal with the fact that no matter how much support you have, it’s always possible that the truth lies elsewhere.
That said, there are good and bad ways to go about making an inductive argument. So let’s look at some of the fallacies one might slip into. (These and a host of other common reasoning problems are discussed in a book called Critical Thinking and Communication: The Use of Reason in Argument. It’s a little dry, but not too technical, and can be a useful resource.)
Begging the Question
Not only is this an annoying fallacy, it’s a frequently-misused phrase. To beg the question is not to raise the question. Rather, it’s to, in essence, turn the question into the answer to the question. Let’s say we’re trying to figure out if someone can be trusted, and you say “We can trust him. He never lies.� I ask you how you know, and you say, “He told me.� The only way “he told me� is useful evidence is if we know the guy is trustworthy. But that’s exactly what we’re trying to figure out!
Post Hoc Fallacy
This one comes from the expression Post hoc ergo propter hoc, which means “After the thing, therefore because of the thing.� To commit the post hoc fallacy is to conclude that one thing caused another just because the former happened before the latter. For example, last year, the Minnesota Twins were having a disappointing season. They traded for an outfielder named Shannon Stewart, and soon after they started winning more games and eventually made the playoffs. Many people ascribed the Twins’ success to Stewart’s arrival – in fact, at least one prominent columnist argued he should be considered the AL Most Valuable Player. The problem is, if you take a look at what the team was doing, their offense was about the same before Stewart’s arrival as after. The big change was that the Twins’ pitchers suddenly started performing better. And since Stewart didn’t do double duty as a pitching coach, it’s very unlikely that his arrival had much to do with that. But people needed to find a clear cut event that they could point to and say, “This is what’s different. This is what’s responsible for the change.� In doing so, they missed the difference between correlation and causation – the trade correlates with the team’s improvement, but it didn’t cause it.
False Analogy
Analogies are frequently used in inductive reasoning – you establish that the situation up for debate is similar to another, more settled situation. From there you can argue that what’s appropriate in the uncontroversial situation is also appropriate in the questionable one. When folks pointed out that the tech stock bubble was like the tulip craze, they were making an analogy that turned out to be very apt – both markets crashed. But it’s very easy to try and equate two things that really aren’t similar, often because of strong emotion. When slaveowners justified, for example, breaking up a family by selling some of its members by appealing to their right to do as they wished with their property, they were engaging in the false analogy fallacy – human beings and inanimate objects in your possession are nowhere near similar enough that one should conclude that you can do to the former everything you can do to the latter.
Unlike the deductive fallacies we discussed before, you can’t necessarily automatically identify these inductive fallacies just by looking at them. The structure of an inductive argument isn’t always readily apparent, and many times the statements offered in support of a conclusion are disputable themselves – and the support for those statements is either implied or absent altogether. It’s important to ask yourself, “What does this person ultimately want me to agree with? And what else do I have to believe in order for this argument to hold together?� Whether or not an analogy is a good one is something that might be debatable, for example. But if that debate is brought into the open, it gives us a better chance of evaluating it and correcting the errors that may have slipped in accidentally.
Inductive reasoning can be messy – but at least it’s flexible. The world we live in just doesn’t operate according to the hard and fast rules of deductive logic all the time. (One might even question whether it does very often.) In the middle of the twentieth century, a group of philosophers advanced a position called logical positivism – one that argued that the laws of logic were fixed, immutable parts of nature, and only conclusions that were based on those laws could be considered trustworthy knowledge. Eventually, most philosophers (and folks outside academia) found themselves taking a more pragmatic approach. As I’ve often said, there’s a reason why criminal courts use the standard “beyond a reasonable doubt� and not “beyond all doubt altogether.� Our experience does not lend itself to absolutes, but it isn’t total chaos either. The rules of reasoning are tools at our disposal to help us navigate through our lives; like any tools, they can be misused, and if you don’t know what you’re doing with them, you can hurt yourself. So keep some of these fallacies and structures in mind, and think safely.
About Dave Thomer
Born and raised in Philadelphia. Studied philosophy at Fordham University in the Bronx, where I made many great friends and met my wonderful wife. We moved back to Philadelphia, where I studied philosophy some more and became a teacher. Online and off, I'm looking for ways that we can be better citizens and build stronger communities.