John Wilkins - “The Discovery of a World in the Moone, or, a Discourse Tending to Prove, that ‘tis probable there may be another habitable World in that Planet”, 1638.
Some of Wilkins’s propositions have been proven true with time: That the Moone is a solid, compacted, opacous body; That the Moone hath not any light of her owne; That there are high Mountaines, deepe vallies, and spacious plaines in the body of the Moone. His explanation of the heliocentric solar system - an idea which he considers likely enough to be true - inspires his pithiest argument: Now if our earth were one of the Planets […] then why may not another of the Planets be an earth? In other respects, alas, his propositions are wide of the mark: That those spots and brighter parts […] in the Moone, doe shew the difference betwixt the Sea and Land in that other World; The spots represent the Sea, and the brighter parts the Land; That there is an Atmo-sphæra, or an orbe of grosse vaporous aire, immediately encompassing the body of the Moone. And, as his final proposition, Wilkins claims that ’tis probable there may be inhabitants in this other World, but of what kinde they are is uncertaine.