Valla and the temporal Arrow

Thinking about interpretation of historical events for long will make one tend into the direction of increasing under-determination. But there are a few things that work like a hard pruning shear and that are not really debated. These have to do with some of the dimensions of our cognition, to put it in terms of Kantian categories, namely that temporally separate things only have one direction of dependence; and that the same macroscopic object cannot be at two locations (that share no spatial overlap) at the same point in time. 

That was basically all that Lorenzo Valla used to dismantle the claims behind the forged Donation of Constantine to Pope Sylvester. Valla argued that certain phrases were in use during the reign of Constantine and certain phrases were not. For example, during the time of Constantine, there were no satraps. Since the Donation assumes that there were satraps as a political title and role, the text shows no understanding of the time of Constantine and therefore cannot be from the time of the reign. 

What that means for an interpretation then is that we have a situation where we have run out of alternatives and ruled them out. As in the old Peanuts joke, there are no oceans (now) in Kansas, nor in North Dakota, nor in Colorado, nor in Arizona, nor in Utah, nor in Wyoming. Given that there is a finite number of states, we can eventually iterate over all of them and determine if they have oceans or not. Thus with the writings from the time of Constantine; eventually we can look through all of them and come up with something like word counts for satrap for each of them. And we can then make a positive statement of an absence: there are no documents from the time of Constantine that recognize satrap as a political title.

We of course immediately see the problem. How did we get this set of dated documents? By some method like Valla's, involving terminus ante quem and terminus post quem. Presumably involving the same logic that Valla just used. For clearly our set of documents cannot use the Donatio itself. There is then a petitio principii in the sense that we already need to exclude the document under consideration in order to make the determination.

But that may be overplaying the hand of the other side. Surely it is good cross-validation practice to go through a canon of writings and see how well, if one document is withheld during training, the separated document holds up when looking at all the other ones as the training corpus. Or perhaps one can cluster the documents by the language and find that the Donatio is an outlier along several dimensions. There is a way that this determination can be made that is not completely dependent on begging the question.

Perhaps the example of the satrap is not the best one either, because that term did exist before Constantine and had become part of the historical discourse since Herodotus (Book III, 89-93).