3. I have held several discussions on this subject with spirits from our world, and I have been told that anyone of sound intellect can deduce from many facts known to him that there are many worlds and people living on them. For it is reasonable to infer that such vast bodies as the planets, some of which are larger than the earth, are not empty masses, created merely to circle the sun and shine their feeble light for the benefit of one world, but they must have some more important purpose than this. Anyone who believes, as each one of us should, that the Deity's sole purpose in creating the universe was to bring into existence the human race, and from this to people heaven - the human race being the seed-bed of heaven - must inevitably believe that, where there is a world, there must be human beings.
[2] The planets visible to our eyes, because they lie within the bounds of the solar system, can be plainly known to be worlds, as being bodies made of earthly matter. This is plain because they reflect sunlight and when seen through telescopes do not show the redness of flame as stars do, but are mottled with dark patches like lands on earth. Another argument is that they revolve around the sun in the same way as the earth, advancing along the path of the zodiac, and so causing years and seasons of the year, spring, summer, autumn and winter. They also rotate about their axes in the same way as the earth, thus causing days and the different periods of the day, morning, midday, evening and night. Moreover, some of them have moons, which are called satellites, travelling around their orbits with fixed periodicity, like the moon around the earth. The planet Saturn, being the furthest from the sun, has also a great shining ring which supplies that world with a great deal of light, even if it is reflected light. Can anyone knowing this and able to think rationally still claim that these are empty masses?