Robson opens by presenting research and case studies showing that highly intelligent, well-educated people are not immune to significant reasoning errors, and in some specific cases are actually more vulnerable to certain types of flawed thinking than people with more average measured intelligence.

Key evidence he presents:

• Studies of "dysrationalia" — a term for the gap between raw intelligence and rational thinking — show that traditional intelligence measures like IQ don't reliably predict good judgment or freedom from cognitive bias
• Robson documents specific historical cases of highly intelligent, credentialed experts making significant, sometimes catastrophic reasoning errors, despite their evident raw cognitive capability
• This opening evidence sets up the book's central puzzle and purpose: identifying the specific mechanisms by which intelligence fails to protect against poor reasoning, and what can be done about it

This opening reframing challenges a common assumption — that raw intelligence reliably produces good judgment — setting up the book's more nuanced exploration of what actually predicts good thinking.