[PROCULUS libro secundo epistularum. ] §50.16.124.prHaec uerba 'ille aut ille' non solum disiunctiua, sed etiam subdisiunctiuae orationis sunt.
[PROCULUS from the second book of Epistles.] These words 'either this or that' are not only disjunctive, but also belong to subdisjunctive statement.
disiunctiuum est, ueluti cum dicimus 'aut dies aut nox est', quorum posito altero necesse est tolli alterum, item sublato altero poni alterum.
A disjunctive statement is, for example, when we say 'it is either day or night', in which once one of them is established, the other must be removed, and likewise once one is removed, the other must be established.
ita simili figuratione uerbum potest esse subdisiunctiuum.
Thus, by a similar configuration, the word can be subdisjunctive.
subdisiunctiui autem genera sunt duo: unum, cum ex propositis finibus ita non potest uterque esse, ut possit neuter esse, ueluti cum dicimus 'aut sedet aut ambulat': nam ut nemo potest utrumque simul facere, ita aliquis potest neutrum, ueluti is qui accumbit.
Now, there are two types of the subdisjunctive: one is when, of the proposed terms, both cannot be the case, but neither can be, as when we say 'he is either sitting or walking'; for just as no one can do both at the same time, so someone can do neither, such as one who is reclining.
alterius generis est, cum ex propositis finibus ita non potest neuter esse, ut possit utrumque esse, ueluti cum dicimus 'omne animal aut facit aut patitur': nullum est enim quod nec faciat nec patiatur: at potest simul et facere et pati.
The other type is when, of the proposed terms, neither cannot be the case, but both can be, as when we say 'every animal either acts or suffers'; for there is none that neither acts nor suffers, but it is possible to both act and suffer at the same time.