5023. There are others, as many as is necessary, who are on the left, in a certain altitude - and some below - chiefly at the left there, who are skilled in the art of being able to bind the thoughts, and also to induce on others the phantasies that the gates are closed; and also, on those who wish to go out, that there are marshy and similar obstructions outside the city. Those who are skilled in such arts are kept there and rewarded. This is permitted for the sake of defending themselves against the evil. Nevertheless, they pick these out, so that they may not be altogether infernal.