When a man finds a conclusion agreeable, he accepts it without argument, but when he finds it disagreeable, he will bring against it all the forces of logic and reason

460 -395 (Age at death: 65 approx.)

http://en.wikipedia.org/wiki/Thucydides
From wikipedia:
Greek historian and author of the History of the Peloponnesian War, which recounts the 5th century B.C. war between Sparta and Athens to the year 411 B.C. Thucydides has been dubbed the father of "scientific history" due to his strict standards of evidence-gathering and analysis in terms of cause and effect without reference to intervention by the gods, as outlined in his introduction to his work.[1]

He has also been called the father of the school of political realism, which views the relations between nations as based on might rather than right

Country: Greece

Type: Prose
Context: Unknown
Cited By: David Menkes