Extinction itself had to be discovered before it could be studied

Kolbert opens with Georges Cuvier, the French naturalist who in the late 18th century examined fossil bones of mammoths and other unfamiliar creatures and concluded, against the prevailing assumption that all created species still existed somewhere on Earth, that these animals had vanished entirely — proposing extinction as a real, demonstrable phenomenon rather than a theological impossibility.

Cuvier went further, proposing that Earth's history included past catastrophic upheavals — a controversial idea at the time, since it clashed with the era's assumption of a stable, unchanging natural order recently created and fundamentally fixed.

Kolbert treats this as the conceptual starting point of the entire book: before scientists could investigate mass extinctions, someone had to first establish that species could disappear permanently and that Earth's history included violent disruptions capable of causing it — an idea that took real intellectual courage to propose against the consensus of the time.

Takeaway: before mass extinction could be studied, someone first had to prove that species can vanish forever — a genuinely radical idea in Cuvier's time.