33 Seven Fallacies of Highly-Human Thinkers
Many sources have identified a host of fallacies we are prone to commit, but much of the discussion stems from a highly influential book, Thinking, Fast and Slow, by Daniel Kahneman. Kahneman provides his own list of fallacies we are prone to use. The following list overlaps a bit with his but also offers some other fallacies that seem to me very common and more relevant to this introduction to epistemology.
1. Anchoring. The thing we learn first often has an overly strong effect over the rest of what we learn, and we make decisions about what to accept or reject on the basis of that first thing. For example, perhaps we learn from Grandpa that the candy store charges too much, and thereafter, we insist that this is true. Every bit of contrary evidence that comes in (“But the chocolate bars are, in fact, cheaper than anywhere else!”) is brushed aside as just a fluke, or a ploy by the candy store to lure in more customers and then overcharge them for other items. But what reason or evidence do we have for believing that the candy store is so devious? Really, it is just that we first learned one thing from grandpa, and then we stuck with it. Our Storymaker makes the first thing a crucial element in the story and uses it as a criterion for deciding what else to add to the stories we make. But of course, it can easily be that the first thing we hear or learn is not reliable—even if it comes from Grandpa!—and is not entitled to this kind of authority.
2. Confirmation bias. We seem to be wired to look greedily for evidence that supports whatever we already believe and to ignore any evidence that suggests otherwise. But this is, if anything, the opposite of what we would want to do if we wanted to be sure that what we believe is true. If we were to try to follow something like the scientific method in forming our own beliefs, we should look instead for good evidence that what we believe is false. And if we find none, then we may tentatively hold on to our belief until further evidence comes in. This bias toward trying to confirm our beliefs seems to result from the way our Checker interacts with our Guesser: the Checker looks to see if a guess is correct and does not look for evidence against the guess.
One illustration of our inclination toward confirmation bias is the “Wason selection task.” We are shown the cards in the diagram below. Each card has a color on one side and a number on the other side. We are asked to determine whether the following rule is true: every card with an even number on one side is red on the other side. To determine whether this rule is true, we are allowed to turn over only two cards. Which two cards should we turn over?
Most people think immediately of turning over the “8” card and the red card, probably because the rule we are thinking of combines even numbers and red cards. So, we want to see whether that connection holds. But in fact, the only way to test the rule is to turn ove