I hate to break it to you, gentle reader, but fake facts are nothing new. We are designed by evolution to invent fake facts, fervently believe in them, and even defend them to the death. Still, there is something about the current epidemic of fake facts that should scare us into action.

Imagine grading everything you ever said according to two criteria: 1) How well it corresponds to what’s actually out there, and 2) what it causes you and others to do. These can be called factual realism and practical realism, respectively, and they are so familiar that we use the word “realistic” in both senses without needing to think about it. If we’re at an art gallery and I comment on how a portrait is realistic, I mean that it corresponds closely to the person being depicted (factual realism). When you outline your latest get rich quick scheme over lunch and I call it unrealistic, I mean that it probably won’t work out well for you (practical realism). All of us are experts at toggling between factual realism mode and practical realism mode as warranted by the situation.

Now here’s the 64 Million Dollar Question (in my youth it was the 64 Thousand Dollar Question, but we must adjust for inflation)—When does practical realism require factual realism, and when does it require departing from factual realism?

The answer to this question is…drum roll, please…”It depends”.

Let’s say that you’re a Master hunter or a Master gardener. You’ve earned the title “Master” because of your detailed factual knowledge of your quarry or the plants under your care. Factual and practical realism go together in these cases.

Now imagine that you’re a member of a group locked in battle for territory with another group. You could regard them as much just like yourself, competing for the same square of ground. Or, you could regard them as inhuman monsters without a shred of decency, utterly unlike yourself and your noble comrades. The first belief is closer to factual reality (which doesn’t deny the possibility legitimate differences in territorial disputes), but the latter belief is likely to be more motivating. Hence, in this and many other cases, a belief can become more practically realistic by becoming less factually realistic.

That’s why fake facts are often so tempting, but they go even deeper. Fake facts have been written into our brains by evolution, which “cares” only about the practical realism of survival and reproduction and nothing about factual realism per se. No organism perceives the world as it really is; only aspects that contribute to its survival and reproduction. The rest of the real world is invisible. We cannot sense gravitational fields or mild electrical currents, although other species can. We see only a narrow slice of the light spectrum and even that is distorted into the perception of discrete colors that do not “really” exist, but help us survive and reproduce better than if we saw the light spectrum as the continuum that it really is. It is amazing and humbling, when we pause to think about it, how much we require the instruments of technology and the theories of science to apprehend factual reality as well as we do.

As for our organs of perception, so also for our beliefs. Our minds are designed by natural selection to distinguish between “us” and “them” and to make false attributions about both categories, especially in situations of between-group conflict. We must work hard to overcome these biases if we wish to know the facts of the matter. Yet, in situations where it is important to know the facts of the matter, it can seem quite “natural” to do so and the punishment for failing to honor the facts can be severe. We toggle back and forth between “true fact” mode and “fake fact” mode with ease.

Let’s don our anthropologist hat to see how this operates in cultures very different from our own. The Mbuti (formerly known as Pygmies) are master hunters of the equatorial African rainforest. In his classic book The Forest People, Colin Turnbull describes a group of men discussing how to organize the day’s hunt. The conversation is entirely in true fact mode, based on their intimate knowledge of the forest and their quarry. Some men are known to be better hunters than others, but the Mbuti (along with most people who live by hunting and gathering) are fiercely egalitarian, so the decision about how to organize the day’s hunt must be made by consensus. This, too, could be discussed in matter-of-fact terms, but that’s not what happens. Instead, the decision is framed in terms of what will “please the forest.” A deity is inserted into a conversation that was otherwise purely a matter of fact. Interesting…

A similar story is told for the master gardeners of Bali by the anthropologist Steve Lansing in his book Priests and Programmers. His informants could talk to him in detail about the facts of the matter, as in this passage: “Because here time controls everything. If there are many rodents and we go ahead and plant rice, obviously we’ll get a miserable harvest. So we organize things like this: when the rodent population is large, we see to it that we don’t plant things they can eat, so that they will all die—I mean, actually, that their numbers will be greatly reduced pretty quickly.” Yet, in the next breath, they could profess belief in an elaborate religion that regulates the maintenance and use of the irrigation system required to grow rice: “Belief…overflowing belief. Concerning Batur temple—really that is the center, the origin of waters, you see. At this moment, the Jero Gde [the high priest] holds all this in his hands.” Very interesting…

Closer to home, imagine that you witness a crime and are called to testify at the court trial. You are made to place your hand on the Bible and say “I swear to tell the truth, the whole truth, and nothing but the truth, so help me God”. Your testimony must stick to the facts, but a deity—the Christian god—was strategically inserted into the conversation, just as a forest deity was inserted into the conversation among the Mbuti about where to hunt. Very, very interesting.

These three examples illustrate one of the most important contexts for the invention of fake facts—to compel us to behave for the benefit of our group, even when it might be against our private interests. This could be discussed in matter-of-fact terms, just as we could regard our enemies as much like us, but that’s not as motivating as the invention of powerful deities that will punish us for failing to place group interests above our private interests. The entire concept of sacredness can be understood largely in these terms. This is why fake facts are ironically needed or at least very useful to enforce truth-telling, as in the case of swearing on a Bible in court.

Thinking clearly about factual and practical realism makes it hard to reject fake facts as categorically bad. Indeed, the reason that we are so gifted at inventing, believing in, and defending them is because they are so good, at least in the evolutionary sense of the word. But that doesn’t make them good in the normative sense of the word. Evolution frequently results in outcomes that are selfish and short-sighted by normative standards—good for me but not you, us but not them, or good for all of us today but not tomorrow.

That is what’s frightening about the current epidemic of fake facts—their use in a way that is clearly detrimental to the common good. We need to recognize the many situations in modern life when behaving for the common good—practical realism—requires understanding the facts of the matter—factual realism. For these situations, we must be strong in our defense of factual realism, so help us God.