Clean your brain, bookseller

Spake Tetrapilotomos:
"Can't understand this. In my bookshelf the Satanic Verses are peacefully embraced by Bible and Koran, and there is no trouble at all. A very touching picture."

Asked I:
And what is it you can't understand?

Spake Tetrapilotomos:
Anyone who would not know that selling books implicates touching books.

Said I:
Sounds paradoxical, indeed.

Spake Tetrapilotomos:
Although it's logic.

Said I:
And the moral of the story?

Spake Tetrapilotomos:
Daily washing doesn't guarantee clean brains.