daf bit: Menachot 34

[cellio]

In a discussion of the proper placement of the mezuzah, the scroll we place on the doorposts of our houses, the g'mara asks the following question: the torah says "you shall write these words on the doorposts of your house" -- doesn't this mean we should write them directly on the stones of the house? Where does the scroll come from? The g'mara answers that in other places that talk about writing it is onto a scroll or parchment -- a bill of divorce, the sotah's cursed water, and the torah scroll written by a king. On the other hand, the torah also says "write" when talking about the memorial stones that the Israelites will erect (containing the torah text) when they enter the land, and that's stone, so maybe we do write on our houses. No, the g'mara continues, we infer the meaning of "writing" from writing that was intended for all time, not for writing that was in its time only -- the laws of divorce, sotah, and torah scrolls remain, but the stones were for that generation only. But wait, another rabbi says -- you're talking about stones, but the torah says write them on your doorposts; how do we know it doesn't mean literally writing on the doorposts? Because when the torah says "and you shall write them" it means a perfect writing (there's some linguistic manipulation going on here), and any writing on stones or wood would be imperfect. Only a scroll can enable perfect writing. (34a)

If you take a close look at a torah scroll or mezuzah -- or any inked calligraphy on vellum or parchment -- you will see that the ink is actually sitting mainly on top of the surface, unlike with paper -- or wood -- where some of it is absorbed. Finished wood of the right type might not behave that way, but that's probably not what people use to make doorposts. I know more about writing than about wood, so I can't carry this analysis much farther.