# Humanity May Not Persist as a Single Species by Martin Rees > “There's an unthinking tendency to imagine that humans will be around in 6 billion years, watching the Sun flare up and die. But the forms of life and intelligence that have by then emerged would surely be as different from us as we are from a bacterium. That conclusion would follow even if future evolution proceeded at the rate at which new species have emerged over the 3 or 4 billion years of the geological past. But post-human evolution (whether of organic species or of artefacts) will proceed far faster than the changes that led to emergence, because it will be intelligently directed rather than being—like pre-human evolution—the gradual outcome of Darwinian natural selection. Changes will drastically accelerate in the present century—through intentional genetic modifications, targeted drugs, perhaps even silicon implants in to the brain. Humanity may not persist as a single species for more than a few centuries—especially if communities have by then become established away from the earth.” > **— Martin Rees**, *2005, Edge Annual Question, “What Do You Believe Is True Even Though You Cannot Prove It?”* ## Sources and Context - **Direct Edge response and surrounding essay:** [Cosmologist, Cambridge University; UK Astronomer Royal; Author, Our Final Hour](https://www.edge.org/response-detail/10620) — Edge published this exact passage in its 2005 Annual Question collection, *WHAT DO YOU BELIEVE IS TRUE EVEN THOUGH YOU CANNOT PROVE IT?*. The response page preserves the surrounding argument and qualifications. - **Complete local collection index:** [[research/Edge 2005 Full Quotation Curation|Edge 2005 Full Quotation Curation]] — retained source-first record for the complete response cohort and this passage's promotion status. ## Related Articles and Collections - **Collection:** [[collections/Edge|Edge]] - **Collection:** [[collections/Machine Succession|Machine Succession]] - **Collection:** [[collections/MARS|MARS]] - **Article:** [[articles/We Were Never Going to Make It|Never Going to Make It!]] - **Article:** [[articles/The Last Migration Will Not Be Human|The Last Migration]] - **Article:** [[articles/Christopher Nolan's Odyssey at the Threshold of Machine Succession|Nolan's Odyssey]] - **Wiki map:** [[wiki/Major Evolutionary Transitions|Major Evolutionary Transitions]] ## Related Topics - [[wiki/Major Evolutionary Transitions|Major Evolutionary Transitions]] - [[wiki/Population Genetics|Population Genetics]] - [[wiki/Molecular Evolution|Molecular Evolution]] - [[wiki/Epigenetic|Epigenetic]] ## Share on Social Media ``` “There's an unthinking tendency to imagine that humans will be around in 6 billion years, watching the Sun flare up and die. But the forms of life and intelligence that have by then emerged would surely be as different from us as we are from a bacterium. That conclusion would follow even if future evolution proceeded at the rate at which new species have emerged over the 3 or 4 billion years of the geological past. But post-human evolution (whether of organic species or of artefacts) will proceed far faster than the changes that led to emergence, because it will be intelligently directed rather than being—like pre-human evolution—the gradual outcome of Darwinian natural selection. Changes will drastically accelerate in the present century—through intentional genetic modifications, targeted drugs, perhaps even silicon implants in to the brain. Humanity may not persist as a single species for more than a few centuries—especially if communities have by then become established away from the earth.” — Martin Rees, 2005, Edge Annual Question, “What Do You Believe Is True Even Though You Cannot Prove It?” https://bryantmcgill.com/simple-reminders-martin-rees-humanity-persist-single-species ```