“Newton’s System of the World and Comets”, 2016-06-13 (; backlinks):
Isaac Newton’s cosmology apparently involved regular apocalypses caused by comets overstoking the furnace of the Sun and the repopulation of the Solar System by new intelligent species. He supports this speculation with an interestingly-incorrect anthropic argument.
Isaac Newton published few of his works, and only those he considered perfect after long delays. This leaves his system the world, as described in the Principia and elsewhere, incomplete, and many questions simply unaddressed, like the fate of the Sun or role of comets. But in 2 conversations with an admirer and his nephew, the elderly Newton sketched out the rest of his cosmogony.
According to Newton, the solar system is not stable and must be adjusted by angels; the Sun does not burn perpetually, but comets regularly fuel the Sun; and the final result is that humanity will be extinguished by a particularly large comet causing the sun to flare up, and requiring intelligent alien beings to arise on other planets or their moons. He further gives an anthropic argument: one reason we know that intelligent races regularly go extinct is that humanity itself arose only recently, as demonstrated by the recent innovations in every field, inconsistent with any belief that human beings have existed for hundreds of thousands or millions of years.
This is all interestingly wrong, particularly the anthropic argument. That Newton found it so absurd to imagine humanity existing for millions of years but only recently undergoing exponential improvements in technology demonstrates how counterintuitive and extraordinary the Industrial & Scientific Revolutions were.