what does the writer want to tell us?*

Sabato wants to show us something.
An idea that is so solid that it thrills.
If the devil is the prince of darkness, it means that he has power over everything that has no light.
If I force my reasoning, I could say that the devil rules in a kingdom of blindness. So, who could it be able to serve the demon? It is so obvious, so obvious... only blind people -people who can't see- can be his servants.
Blind people that moves in tunnels and subways and share a secret connection between them to obey the orders of the demon.

The light of reason, the power of the logic till the last consequences can be so dangerous that takes someone to have this kind of thoughts. The idea is so full of that logic that it scares, probably because it is touching slightly the insanity.

* i look so serious when i write the title of this post.