The Belief You Need to Kill Today

The HMS Beagle rocked gently in Galápagos waters. Charles Darwin, barely twenty-six, clutched a finch in his hands. Its beak was wrong. Everything he'd been taught at Cambridge, everything he believed about God's perfect creation, insisted this bird's beak should be different. He wrote in his notebook that night: "It is like confessing a murder."

What he meant was the realization that species might change. That they weren't fixed by God's hand at creation. He was describing something as painful as killing a person—the death of his own certainties.

For twenty years after that voyage, Darwin became his own fiercest critic. Each morning, he'd wake up and attack yesterday's conclusions. He called it his "golden rule." To immediately write down every observation that contradicted his theory. Our minds, he knew, are quick to forget what threatens our beliefs.

His study at Down House became a laboratory of self-doubt. Letters flew back and forth with scientists who disagreed. He cultivated opposition like others cultivate apple orchards. When a colleague pointed out a flaw, Darwin thanked him. When evidence contradicted his work, he celebrated.