nor is appetizing an opposite to disgusting. It can be convenient to mis-represent such pairs as like the two ends of a single line, but doing this too frequently could lead to one-dimensional ways to think, no matter that such two-part distinctions may blur other dissimilarities between pairs of substantially different ideas, by leading us into supposing that both sides of each pair are almost the same—except for having ‘plus’ or ‘minus’ signs! Thus, representing feelings in terms of intensities can simplify how we make our decisions. However, I suspect that when we face more difficult choices, then we use more complex ways to settle conflicts among competing views or ways to think.[194]
Structural vs. Functional descriptions. Many of our distinctions are based on ways to make connections between what we learn about things and what we learn about using those things. Accordingly, it is often convenient to classify the parts of an object as playing ‘principal’ vs. ‘supporting’ roles—just as we did for ‘a chair’ in §8-3, where we identify the seat and back as its essential parts, and its legs and parts as merely serving to sustain them.[195]
Certainly, two-part distinctions can be useful when we need to choose between alternatives—but when that fails, we may have to resort to more complex distinctions. For example, when Carol is trying to build that Arch, it will sometimes suffice for her to first describe each block as being short or tall, or narrow or wide, or thin or thick; then she may only need to decide which of those distinctions is relevant. However, on other occasions, Carol may need to find a block that satisfies some more elaborate combination of constraints that relate its height, width and depth; then she can no longer describe that block in terms of only a single dimension.
Inborn Brain-Machinery. Another reason why we tend to think in terms of pairs could be that our brains are innately equipped with special ways to detect differences between pairs of mental representations.
In §6-4 we mentioned that when you touch something very hot or cold, the sensation is intense at first, but then will rapidly fade away—because our external senses mainly react to how things change in time. (This also applies to our visual sensors, but we’re normally unaware of this because our eyes are almost always in motion.) If this also applies to sensors inside a brain, this would make it easy to compare a pair of descriptions, simply by alternately presenting them. However, this ‘temporal blinking’ scheme would work less well for describing the relationships of more than two things—and that could be one reason why we are less proficient at making three-way comparisons. [See SoM §23.3 Temporal Blinking]
When is it appropriate to distinguish between only two alternatives? We often speak as though it is enough to classify a new thing or event in ‘yes or no’ terms like these:
Was this a failure or a success?
Should we see it as usual or exceptional?
Should we forget it or remember it?
Is it a cause for pleasure or for distress?
Such two-part distinctions can be useful when we have only two options to choose among. However, selecting what to remember or do will usually depend on making more complex decisions like these:
How should we describe this event?
What links should we connect it with?
Which other things is it similar to?
What other uses could we make of it?
Which of our friends should we tell about it?
More generally, it usually little sense to commit ourselves, for all future times, about which objects to like or dislike—or about which persons, places, goals, or beliefs we should seek or avoid, or accept or reject—because all such decisions should depend, upon the contexts that that we find ourselves in.
Accordingly, it seems to me that there is something wrong with most dumbbell distinctions: those divisions appear to be so simple and clear that they seem to be all that you need—and that satisfaction tempts you to stop. Yet most of the novel ideas in this book came from finding that two parts are rarely enough—and eventually my rule became: when thinking about psychology, one never should start with less than three hypotheses!
Why do people find it so hard to classify things into more than two kinds? Could this be because our languages don’t come with verbs for speaking about trividing things? We all are good at ‘comparing’ pairs of things, and making lists of their differences—but few of us ever develop good ways to talk or to think about trifferences—that is, about relationships among triplets of things. Could this be because our brains don’t come equipped with adequate, built-in techniques for this?
Perhaps this could be in part because a typical child’s environment contains almost no significant ‘triplets’ of things. A typical two-year-old has a pair of hands, and is taught by a pair of parents to learn some way to put on a pair of shoes—and, soon, that typical two-year-old will learn to understand and to use word “two.” perhaps from being familiar with such pairs as two hands or two shoes. But it usually takes yet another full year for that child to learn to use the word “three.”
Robert Benchley: “There are two kinds of people in the world: those who believe there are two kinds of people in the world and those who don’t.”
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