Every animal on earth has a set of correspondences with the environment around it, and some of those correspondences far exceed ours. Humans can perceive only thirty percent of the range of the sun's light and 1/70th of the spectrum of electromagnetic energy. Many animals exceed our abilities. Bats detect insects by sonar; pigeons navigate by magnetic fields; bloodhounds perceive a world of smell unavailable to us.
Perhaps the spiritual or "unseen" world requires an inbuilt set of correspondences activated only through some sort of spiritual quickening. "No one can see the kingdom of God without being born from above," said Jesus. "The man without the Spirit does not accept the things that come from the Spirit of God, for they are foolishness to him, and he cannot understand them, because they are spiritually discerned," said Paul. Both expressions point to a different level of correspondence available only to a person spiritually alive.
