Summary
This quote suggests that a biography should be written from the perspective of an individual who harbors animosity or hostility towards the person being written about. By having an "acute enemy" as the biographer, it implies that they would delve deep into uncovering the subject's flaws, secrets, and shortcomings, providing an unbiased and critical account of their life. It implies that a friend or admirer may be more inclined to overlook or sugarcoat certain aspects, while an enemy would be driven to expose the truth regardless of its negative implications.