Aristotle defined humans as the rational animal. But he was wrong! The human mind is riddled with cognitive biases. At last count, there are something like 150 named cognitive biases—confirmation bias, in group bias, loss aversion, the Ikea effect, the halo effect, endowment effects. And every time you turn around, some clever psychologist is naming a new one. But whatever you name them, cognitive biases are a problem. They distort gender relations, racial relations, employment, education, politics, even science. And we’re mostly not even aware of them! That makes them very hard to correct. Indeed, it is not at all obvious that we can correct them. They may, in fact, be entirely beyond our control.

Here’s an example of cognitive bias at work. Take a group of teachers. Randomly divide them into two groups. Give each group the exact same set of papers to grade. Put African American sounding names on the one set, Anglo sounding names on the other. The African American sounding names will elicit lower grades than the Anglo sounding names. Before you conclude that the teachers are just bigots, you should know that you get the same result for all different sorts of people, including the most open minded people in the world, the kind who insist that they would never intentionally discriminate against anybody. We ALL suffer from this sort of implicit cognitive bias: black, white, male, female. It doesn’t matter.

Now think about how we might try to overcome our cognitive biases. Take our teachers. Maybe we should just instruct them to try harder, to focus like a laser on the on the quality of the papers they are given and to make concerted efforts to block out extraneous factors. If you give teachers an instruction like that, they will actually try hard to follow it. But ironically, for some cognitive biases, trying may actually make it worse. Trying can biases you toward thinking you’ve succeeded. Once you think you’ve succeeded in eliminating bias, you may think to yourself “Look, ma! No more bias.” And that can lead you to think, “This is what I think, and I’m not biased, so it must be true!” There is even a clever name for this effort induced cognitive bias. It’s called the “I think it, therefore it’s true” effect. The point is that we can’t just will our biases away. That’s because many of them are the result of unconscious mechanism that are beyond the reach of our conscious control.

You might think that education and training would help. But there’s little to reason to take education and training as a cure all for our cognitive biases. Indeed, highly educated and trained scientists still suffer from cognitive biases. They even suffer from cognitive biases that are peculiar to scientific research. This shows that no domain of human cognition is immune to the effects of cognitive bias. And that includes us oh-so-rational philosophers.

Before we throw up our hands in despair and conclude that the mind is just a junkyard littered with cognitive biases, it’s important to realize that the mind is also the product of evolution. And evolution doesn’t do junkyards. It does beneficial adaptations. And though cognitive biases may seem the very opposite of beneficial to us now, back in the day, on the Pleistocene savannah, they played a very adaptive role. In those circumstances, if you took time to consider things from all angles, you wouldn’t survive. As a consequence, natural selection designed our brains to make quick and dirty decisions on the fly. Sure, they didn’t always yield the truth. But they helped to keep our forebears alive. This means that perhaps we should regard our cognitive biases as features rather than bugs!

The problem with this line is that we’re not on the Savannah any more. Quick and dirty reasoning may have been good enough for hunter gatherers, but won’t necessarily cut it in our much more complex environment. To thrive in today’s world, we need to “debias” our minds—evolution be damned! Not that that would be an easy task. But it may not be as hard as one might think. Take those teachers. They can debias just by anonymizing student papers. That doesn’t take Herculean effort. And it doesn’t take a lot of education either.