Cosmic pluralism

The debate over pluralism began as early as the time of Anaximander (c. 610 – c. 546 BC) as a metaphysical argument,[2] long predating the scientific Copernican conception that the Earth is one of numerous planets.

Cosmic pluralism was a corollary to notions of infinity, and the purported multitude of life-bearing worlds were more akin to parallel universes (either contemporaneously in space or infinitely recurring in time) than to different solar systems.

[10][11] Giordano Bruno introduced in his works the idea of multiple worlds instantiating the infinite possibilities of a pristine, indivisible One.

As greater scientific skepticism and rigour were applied to the question, it ceased to be simply a matter of philosophy and theology and was properly bounded by astronomy and biology.

Flammarion was one of the first people to put forward the idea that extraterrestrial beings were genuinely alien, and not simply variations of earthly creatures.

[15] In the late nineteenth and twentieth centuries, the term "cosmic pluralism" became largely archaic as knowledge diversified and the speculation on extraterrestrial life focused on particular bodies and observations.

Carl Sagan and Frank Drake, for instance, could well be considered "pluralists" while proponents of the Rare Earth hypothesis are modern skeptics.

Modern Islamic scholars like Abdullah Yusuf Ali point to the Qur'an (42:29) to argue for life on other planets: "And among His Signs is the creation of the heavens and the earth, and the living creatures that He has scattered through them".