Apology for Raymond Sebond is the longest and most famous essay in Essays. Although it begins as a defense of the theologian Raymond Sebond, it becomes a wide-ranging meditation on human knowledge, faith, and humility.
Its core ideas include:
Human reason is limited. Montaigne argues that people greatly overestimate the power of reason. We often mistake opinion, custom, and pride for certain knowledge.
Faith is not based on logic alone. He suggests that religious faith ultimately rests on God's grace rather than on philosophical arguments. Reason can support faith to a point, but it cannot prove everything.
Humans are not the center of creation. Montaigne criticizes human arrogance, arguing that we wrongly imagine ourselves superior to all other creatures.
Animals may be wiser than we think. He gives many examples of animal intelligence and behavior to challenge the assumption that reason makes humans uniquely superior.
Skepticism is healthy. Influenced by the ancient skeptic Sextus Empiricus, Montaigne believes we should question our certainty. Admitting "I don't know" is often wiser than making confident claims without evidence.
Custom shapes our beliefs. Much of what we think is true comes from the culture we were raised in rather than from objective reasoning.
Humility is a virtue. Recognizing our intellectual limitations makes us more tolerant, less dogmatic, and more open to learning.
The essay's famous underlying question is "What do I know?" ("Que sais-je?"), which became Montaigne's personal motto. Rather than leading to despair, this skepticism encourages modesty, curiosity, and a recognition that certainty is rare.
Today, the essay is regarded as one of the foundational works of modern philosophical skepticism and had a profound influence on later thinkers such as Blaise Pascal, René Descartes, and David Hume.