How can so many people believe things that are demonstrably false? The question has taken on new urgency as the Trump administration propagates falsehoods about voter fraud, climate change and crime statistics that large swaths of the population have bought into. But collective delusion is not new, nor is it the sole province of the political right. Plenty of liberals believe, counter to scientific consensus, that G.M.O.s are poisonous, and that vaccines cause autism.

The situation is vexing because it seems so easy to solve. The truth is obvious if you bother to look for it, right? This line of thinking leads to explanations of the hoodwinked masses that amount to little more than name calling: “Those people are foolish” or “Those people are monsters.”

Such accounts may make us feel good about ourselves, but they are misguided and simplistic: They reflect a misunderstanding of knowledge that focuses too narrowly on what goes on between our ears. Here is the humbler truth: On their own, individuals are not well equipped to separate fact from fiction, and they never will be. Ignorance is our natural state; it is a product of the way the mind works.

What really sets human beings apart is not our individual mental capacity. The secret to our success is our ability to jointly pursue complex goals by dividing cognitive labor. Hunting, trade, agriculture, manufacturing — all of our world-altering innovations — were made possible by this ability. Chimpanzees can surpass young children on numerical and spatial reasoning tasks, but they cannot come close on tasks that require collaborating with another individual to achieve a goal. Each of us knows only a little bit, but together we can achieve remarkable feats.