Big Think

These two freak accidents explain why you're alive today | Sean B. Carroll

18 snips
Aug 25, 2025
Biologist Sean B. Carroll, author of 'A Series of Fortunate Events', explores the improbable chain reactions that allowed human life to flourish. He discusses two pivotal freak accidents: the asteroid that caused the dinosaurs' demise and a tectonic collision that ushered in the Ice Age. Carroll dives into how these events transformed our planet, paving the way for mammals and ultimately, hominids. He also muses on the mind-boggling chances that make our existence possible in the grand tapestry of life.
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INSIGHT

Microbial Life Is The Likely Cosmic Norm

  • Microbial life is likely abundant in the universe, but complex animals are probably rare compared to microbes.
  • Sean B. Carroll argues most extraterrestrial life, if present, will resemble microbes rather than giraffes or redwood trees.
INSIGHT

Earth's History Was A Random Walk

  • Earth's history is not a straight progression but a random walk shaped by geological and biological coupling.
  • Carroll emphasizes many contingent events across scales had to align for humans to exist.
ANECDOTE

A New Origin Story Starts 66 Million Years Ago

  • Carroll frames the last 66 million years as a new origin story beginning with the asteroid reset.
  • He prefers focusing on this era because it's more concrete than the murky origin-of-life events 3.8 billion years ago.
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