How does Michel de Montaigne’s essay style differ from a formal treatise?

Michel de Montaigne’s essay style differs significantly from a formal treatise, which traditionally aims to treat a serious theme with consistent, didactic structure.1

In contrast, Montaigne’s Essays—a term he coined to mean "attempts"—are characterized by:

• Informal and Personal Tone: Rather than transmitting proven knowledge or confident opinion, his writing is a project of trial and error, reflecting an intellectual attitude of continuous questioning and assessment.23
• Lack of Artificial Structure: He refused to impose a false unity or artificially organized stages on his work. Instead, his thoughts appear as they occurred to him, following the natural, roaming movement of his mind.24
• Self-Exploration: While a treatise might focus on abstract generalizations, Montaigne focused on the concrete reality of his own body-and-mind self, using his own experience as a mirror for the human condition.24
• Stylistic Flexibility: His style is marked by multiple digressions, wandering developments, and a concrete vocabulary that maintains the freshness and immediacy of living thought, rather than the rigid rhetoric of a formal treatise.24