Status Updates From La Guerre du Péloponnèse

Thucydides identifies confirmation bias and motivated reasoning long before modern psychology:

“For it is a habit of mankind to entrust to careless hope what they long for, and to use sovereign reason to thrust aside what they do not desire.”

“The present prosperity had persuaded the Athenians that nothing could withstand them, and that they could achieve what was possible and what was impracticable alike, with means ample or inadequate it mattered not. The reason for this was their general extraordinary success, which made them confuse their strength with their hopes.”