Also the dough strengthening effect of old dough cannot be harnessed simply by "corporeal contact". It isn't magic, or osmosis for that matter.
Dear Enter8, I thank you for your input. Allow me to briefly tell you about one of my several trials of carefully experimenting with the method of juxtaposing, not mixing, new dough batch with old dough batch. In one of my early experiments, I prepared a 2.5 kilo batch of dough, using Caputo Pizzeria flour, 67% hydration, 3% salt, and 0.035% fresh yeast. I let the dough mass undergo 18 hours of initial fermentation at room temperature. This dough was specifically prepared to serve as my old dough after 18 hours of its initial fermentation.
By the 17th hour, I prepared another 2.5 kilo batch of dough, utilizing the same recipe and percentages as above, except my fresh yeast percentage was this time figured at 0.05%. By the 18th hour, I divided the the new dough batch in two halves. I placed the first half (hereinafter "A") juxtaposed with the 18-hour old dough in one container, and I placed the other half (hereinafter "B") all alone by itself in a separate container. Thereafter, I let "A" and "b" undergo initial fermentation for 20 hours at room temperature. After 20 hours, I formed dough balls out of "A" and "b", placed them inside dough trays, and let them rest for 7 hours at room temperature. After 7 hours, "A" dough balls appeared much puffier than "B" dough balls. Moreover, upon physical examination, I noticed that "A" dough balls had tougher skins than "B" dough balls'. At last, I opened "A" and then "B" dough ball in order to draft dough discs. "B" proved to be much easier to open than "A". In fact, I had to manhandle "A" in order to open it into a disc. "A" was indubitably more elastic and less extensive than "B". (By the above account, I am by no means implying that this is how Da Michele carries out the method, if at all. The way I executed the method was for sheer experimental and observational purposes.)
Therefore, at this stage of my ongoing experiments, my empirical data seem to challenge your assertion: ". . . The dough strengthening effect of old dough cannot be harnessed simply by 'corporeal contact'." There seems to be some kind of causation, definitely not "magic", between the old and new dough. If you decide to conduct an experiment like this, I would greatly appreciate it if you share your data here with us.
For whatever it's worth, my experiments also seem to indicate that there might be some sort of causal relation between intensification of the charred blisters appearing on the cornicione (baked out of a new dough) and the age
of an old dough juxtaposing the new dough during its initial fermentation. The older the old dough becomes (hence the more acidified it becomes, up to a point), the more over-dramatized the blisters seem to become on the cornicione of the new dough. The picture, below, is an example, which appears as though the dough was cold fermented, whereas it was initially fermented for 20 hours at room temperature (70 to 74ºF) while adjoining a 42-hour old dough, and thereafter it rested as dough balls for 5 hours at room temperature. Good day!