The problem with human imagination is really two problems. One is that our imagination is very limited. Thus, for example, I can’t properly imagine the life, or even the schedule, of someone who has two children. The second problem is that we trust our puny imagination a huge deal, enough that we accept its testimony despite perfectly good evidence to the contrary. Thus, for example, an academic with a young child might say things like “they told me that I won’t get any research done the first few months but…. I guess I didn’t take them seriously!”. In other words, he received reliable information but ignored it because his imagination told him he could just get work done when the baby is asleep.
My favorite cases involve not believing a person when she talks about her inner life. Far be it from me to think that people are never wrong about their inner lives, but when a person tells you she thinks or feels or wants something, the simple fact that you can’t imagine thinking or feeling or wanting it is not in itself a reason to doubt her. I once told a relative stranger that though I grew up in a certain country, I do not feel identified with it. The man said “that’s highly unlikely”. I am still a little angry at the person telling me what I feel, but I don’t have the right to feel superior to him. After all, for decades, I believed that any person who claims to be “full” after a salad – a mere salad! – is either lying to me or lying to herself. To my defense, there exist some people who confess that they have kidded themselves on this particular topic, but I admit that the main reason I failed to believe people who claim to be full after a salad is that I can’t properly imagine being full from eating (only) a salad. That’s a bad reason.
There are two common types of situation in which the problem with human imagination raises its ugly head. One is what I call Someone Else’s Problem cases, or at least that’s what I call them when I give a talk. To myself I call them Giraffe Cases, because of a meme I saw on Facebook. The meme asks if it ever occurred to you that when a giraffe has coffee, the coffee is cold by the time it reaches its stomach. It answers that of course it hasn’t, because “you only think about yourself”. The truth beyond the meme is that we are bad at imagining the facts of someone else’s life if we never faced the same tasks she does. I have read that if you are a poor kid in America, you can fail a school assignment because your parents can’t afford crayons, or, later, because you don’t have enough gas to drive to the library. If one has never been a poor kid in America, one is unlikely to imagine this fact. Now think of how many little facts like that there must be. Together, they add up to something that feels like a huge epistemic barrier to a rich person “getting” poverty in America – an almost “what is it like to be a bat”-grade one. The barrier is particularly devilish because people, trusting their imagination, often fail to see it.
The other type of situation I have in mind I like to call Runaway Simulation – the salad thing would be one such case. A common theory holds that when we try to figure out another human being we start by imagining ourselves in her place. That is simulation. Runaway simulation is when you continue to assume the other human is just like you despite screaming evidence to the contrary. Sometimes I talk to people and they start yawning. I feel bad: am I boring them that much? Then slowly, people start saying they have to go. I feel terrible: did I say something wrong? Then someone mentions the obvious fact that it’s midnight and she is tired. I know, of course, that not everyone is a night owl like me, whom only a very, very boring tale would cause to yawn as early as midnight, and yet my visceral feeling remains the following: “what do you mean “it’s midnight”? You’re half my age!!! Are you sure I didn’t say something wrong?”.
As the parenthood case shows, these barriers to knowing other people can also be barriers to knowing future selves. This gets us to the subject of experience. Experience packs immense epistemic wallop: it is often believed that there are many things that you can’t know unless you have “been there”. Some people, like my friend Laurie Paul, seem to think that this is because there exists, in such cases, a kind of experiential knowledge (“what-is-it-like”) that is not reducible to just plain knowing-that. But I suspect there is no need to conclude that becoming a parent is quite this much like gaining a new sense modality. Much of the epistemic magic of experience can be explained in that it is often the only effective solution to the problem with human imagination, which prevents us from just-plain-knowing-that many things.