Abstract

While it is often supposed that the idea that aliens may exist is a recent idea, this is not supported by the actual history of astronomy. This talk will survey the work of Kepler and Galileo, the two major astronomers in the first part of the 17th century, with an emphasis on what they had to say about aliens. Both of them thought it likely that the Moon was inhabited by rational beings, but their reasoning owed more to theological principles than scientific evidence. I will then review the impact of their work on the thought of the English clergyman and natural philosopher John Wilkins, who was a co-founder of the Royal Society, and author of the first book written in English advocating an inhabited Moon.