It is conceivable that in some small grain of sand which we can hardly perceive there is hidden a whole world in which there is an immense number of living beings so small that they escape not only our perception, but also the perception of those tiny living beings which we hardly observe under a microscope. Is it not possible that there be a long series of such worlds, which, with respect to one another have the same relation as our single grain of sand has to the whole world? And I frequently meditate on this and think about those large cakes of cheese inside of which there frequently are very tiny insects. But there could be also others, much smaller, which escape the power of our microscopes; very little spheres, below all our sensory perceptions, are for them what the earth is for us; yet, there they have their own provinces and kingdoms. Their astronomers, looking through their telescopes, observe other little globes of the same material around them which they will regard as being very far away, their distance measuring an immense number of their feet and cubits. Their philosophers are proud of their knowledge of their little grains, although no one of them has ever penetrated to the crust nor can ever acquire any knowledge of it….