6812. Spirits belonging to Mercury possess more knowledge about real things than all other spirits possess - things both within our solar system and also outside it in starry space. Once they have acquired such knowledge they commit it to memory and also recall it as often as anything similar comes their way. This plainly shows too that spirits' memory is far more perfect than men's, and also that spirits commit to memory what they hear, see, and discern, most especially the kinds of things that give them delight, like those spirits from Mercury who are delighted with knowledge about real things. For what gives delight and is loved flows into the mind of its own accord so to speak and remains; nothing else goes in, but merely touches the surface and slips away.