Day: February 27, 2026
02/27/26
Book Freak #198: How We Know What Isn’t So
The Fallibility of Human Reason in Everyday Life
02/27/26
The Fallibility of Human Reason in Everyday Life
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Cornell psychologist Thomas Gilovich examines the cognitive, social, and motivational processes that lead us to believe things that simply aren’t true — revealing that our false beliefs aren’t products of irrationality, but of flawed rationality applied to incomplete information.
Our brains are pattern-recognition machines that often work too well. We see meaningful clusters in random data, believe in “hot hands” in basketball when the streaks are statistically normal, and find significance in coincidences that are mathematically inevitable. The clustering illusion makes us trust our intuitions about randomness when we shouldn’t.
When examining evidence, we see what we expect to see and conclude what we expect to conclude. Information consistent with our existing beliefs is accepted at face value; evidence that contradicts it is scrutinized and discounted. Worse: for conclusions we want to be true, we ask “Can I believe this?” — but for unwelcome conclusions, we ask “Must I believe this?”
The false consensus effect leads us to overestimate how much others share our beliefs. Because we associate with like-minded people and disagreement often stays hidden, we don’t subject our beliefs to healthy scrutiny. This social bubble reinforces false beliefs and makes them feel like common sense.
Humans are extraordinarily good at generating ideas, theories, and explanations that sound plausible. We are far less skilled at rigorously testing them. We prefer black-and-white thinking over shades of gray, and we’ll always be tempted to hold oversimplified beliefs that feel satisfying even when reality is more complex.
“For desired conclusions, we ask ourselves, ‘Can I believe this?’, but for unpalatable conclusions we ask, ‘Must I believe this?’”
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