How did Thucydides test the accuracy of reports from eyewitnesses?

Thucydides approached the task of historical documentation with a commitment to accuracy that rejected hearsay and personal impressions. When reporting on events he did not personally witness, he employed a rigorous method of inquiry to verify information.12

He recognized that eyewitnesses were often unreliable due to two primary factors: faulty memory and personal bias. To mitigate these issues, he conducted thorough investigations, carefully cross-referencing reports to ensure his narrative remained objective and precise. Even when he had personally observed a battle or event, he maintained this standard of exhaustive inquiry rather than relying solely on his own perspective.12

His methodology was driven by a desire to establish a diagnostic science of history, intended to be useful for future generations rather than to provide immediate entertainment. By avoiding the "storytelling" approach of his predecessors, he sought to present a clear, accurate account of the Peloponnesian War that could withstand the test of time.12