How would you explain the key concepts in your own words?

Synthesized answer

The provided passages do not contain information explaining the key concepts of Michel de Montaigne's *Essais* in my own words. The passages only offer the title of the work, the author, his lifespan, a description of the content as "the complete essays," and categorization as "French essays" [Passage 1].

Therefore, I am unable to provide an explanation of the key concepts.

Synthesized from the book passages below. Chat with the book on Feynman for follow-up.