Why is Thucydides considered a founder of critical historical writing?

Thucydides is considered a founder of critical historical writing because he moved away from the "storytelling" approach of his predecessors, such as Herodotus, to establish a diagnostic, scientific method of history. His work, the History of the Peloponnesian War, is recognized as the first recorded political and moral analysis of a nation’s war policies.123

His critical approach was defined by several key principles:

• Rigorous Inquiry: He did not rely on general impressions or unverified reports. When he could not witness events himself, he carefully cross-examined eyewitnesses, accounting for their potential bias and faulty memories.12
• Impartiality and Accuracy: He maintained a passion for truth, striving to remain free from partiality. His narrative is noted for its chronological precision, which is supported by contemporary evidence, such as recorded eclipses and stone inscriptions.4
• Focus on Human Nature: Thucydides believed that because human nature remains constant, the patterns of the past would likely repeat. He wrote not for immediate popularity but to provide a useful, lasting analysis for future generations to understand the complexities of human behavior in times of conflict.12
• Analytical Depth: He used speeches to explore the motives and ambitions of leaders, while his narrative provided a clinical, objective examination of political and social phenomena, such as the effects of plague or the moral decay caused by civil strife.124