Victor Hugo's quote "A fixed idea leads to madness or heroism" from his novel "Ninety-Three" suggests that a strong conviction can drive individuals to extreme actions. When someone becomes obsessed with an idea or belief, it can push them to the brink, resulting in either irrational behavior or valiant acts. This duality reflects the complex nature of human motivation and the consequences of unwavering dedication.

In "Ninety-Three," Hugo explores the ramifications of such fixed ideas during the tumultuous period of the French Revolution. Characters in the novel embody this struggle, highlighting how intense beliefs can lead to both noble sacrifices and tragic outcomes. Ultimately, Hugo’s insight serves as a reminder of the power of conviction and the fine line between greatness and insanity.