And Swedenborg himself saw birds during his sojourns in the Spirit World and it was revealed to him that -- in the Grand Man -- rational concepts are seen as birds. Because the head corresponds to the heavens and the air. He actually experienced in his body the fall of certain angels who had formed wrong opinions in their community about thoughts and influx -- he felt a terrible tremor in his sinews and bones -- and saw one dark and ugly bird and two fine and beautiful. And these solid birds were the thoughts of the angels, as he saw them in the world of his senses, beautiful reasonings and ugly falses. For at every level everything corresponds, from the most purely material to the most purely divine in the Divine Human.