Three levels of understanding and why most of us live at the first When Richard Feynman was a boy, his father took him for walks in the woods outside New York City and pointed out the birds. Other fathers named the birds. Feynman’s father did something different. He would say: “See that bird? It’s a… Read more

Why the strength of a conviction is not evidence of its truth Think about the last time you genuinely changed your mind about something important. Not refined your position, not updated a minor detail, but actually reversed a significant belief: concluded that what you had been confident about was wrong and adopted the opposing view…. Read more

How the mind systematically misleads itself In the spring of 1972, the psychologist Amos Tversky invited a group of physicians to estimate the probability that a hypothetical patient had lung cancer, given a positive result on a diagnostic test with known sensitivity and specificity. The physicians were experienced, the scenario was realistic, and they had… Read more

The most important distinction we are probably not making In ordinary conversation, the words “know” and “believe” are used almost interchangeably. A person who says “I know the restaurant is on the left” and a person who says “I believe the restaurant is on the left” are taken to be expressing different degrees of confidence… Read more

How to communicate with someone whose framework differs from one’s own at the level of what counts as evidence Imagine a conversation about vaccination between a physician and a parent who believes that vaccines cause harm. The physician presents the clinical trial evidence: large, independently replicated, methodologically rigorous studies showing both the safety and the… Read more