421. To this I should add the following, that in the spiritual world I have seen people who, from the visible phenomena of the world, confirmed themselves on the side of nature to the point that they became atheists, and in a spiritual light their intellect appeared open below but closed above, for the reason that in thought they had looked downward to the earth, and not upward to heaven. Above the sensory level, which is the lowest level of the intellect, a kind of veil appeared, in some cases flashing with a hellish fire, in some cases as black as soot, and in some cases as pale as a corpse. Let everyone guard himself, therefore, from confirmations on the side of nature. Let him confirm himself on the side of the Divine. There is no lack of material for it.