Is it probable for Europe to be inhabited and not the other parts of the world? Can one island have inhabitants and numerous other islands have none? Is it conceivable for one apple-tree in the infinite orchard of the Universe to bear fruit, while innumerable other trees have nothing but foliage?

In: Adam Starchild (ed.), The Science Fiction of Konstantin Tsiolkovsky, Dreams of the Earth and Sky (pp. 153-154)