Complex sentence: Lee Smolin, a physicist at the Perimeter Institute first popularized in his 1997 book The Life of the Cosmos the concept that a cosmological natural selection (otherwise known as the Fecund universes theory) might occur via the same rules as those which apply in biology.
Split into simpler sentences: Lee Smolin, a physicist at the Perimeter Institute first popularized in his 1997 book The Life of the Cosmos Smolin, Lee 1997. Oxford University Press the concept that a cosmological natural selection (otherwise known as the Fecund universes theory) might occur via the same rules as those which apply in biology.