5576. The genii, however, are, on the contrary, opposite to the flesh and heart; thus, the bulk of them become as it were bones, or as it were ossifying, cartilaginifying flesh; for they are so entirely opposed to good, in greatest and least things, that there is no soundness in them: they are opposite to the truly human voluntary faculty. In their hells, they at first appear like scarcely visible flying things. They flee from one another, because one is not able to bear the sphere of another's thoughts; for there is perpetual collision. Hence, they make themselves invisible. He who does not think similarly to another in the other life, is invisible to the other.