I’m deep in the throws of the early research stages of a new paper, which means I need an outlet for collecting information and sorting out thoughts…i.e., I need to write blog posts! This will be the first of perhaps more than one posts where I provide brief excerpts on modal and temporal logic from various texts that are not currently translated and have not been discussed much (if at all) in the secondary literature. I’m not sure what of this will eventually result in a paper, but you won’t know what’s in the texts until you look at them…
I’m starting with texts in volume 2 of de Rijk’s Logica Modernorum (despite it being on “the origin and early development of the theory of supposition”, almost every text in that volume says something about modality, usually in the context of the modal syllogistic).
This text exists in a single manuscript, and de Rijk says “I think, it may have come into existence in the third quarter of the twelfth century” (II.1:398).
The discussion of modality occurs in Part III “On the Conclusion” of the treatise. What follows is my (very rough; with some assistance at the very end from the lovely folks in the Medieval Logic FB group) translation of II.2:207-208:
Of categorical propositions, some are modal, others are of inherence (de inesse). [A proposition] of inherence or of simply inherence (de simplici inherentia) is that in which a predicate is attributed to a subject without determination or is removed [from the subject] simply, as in “Socrates is a man”, “Socrates is not a man”. A modal [proposition] is that in which a predicate is attributed to a subject with a determination, as in “Socrates necessarily is a man”, “Socrates contingently is white”. And those propositions are called “modal” by means of the mode which is put into it, namely “possible”, “impossible”, “contingent”, “necessary”. However, “modes” are so-called because they modify, that is determine, the inherence of the predicate.
Further, it must be known that this label “modal proposition” can be taken not only broadly but also strictly or very strictly. [Taken] broadly as in Boethius in the Commento, whereby all propositions in which some adverbial determinant is put down are said to be “modal”. Whence these are modal [propositions], according to Boethius: “Socrates reads well”, “Socrates disputes prudently”. It is taken strictly in which one of these modes is put down: “true”, “false”, “possible”, “impossible”, “contingent”, “necessary”. It is taken most strictly in which one of these modes is put down: “possible”, “impossible”, “contingent”, “necessary”. And it is according to that usage that Aristotle speaks of the modes in the Periermenias. And according to this, those propositions in which these words “true”, “false”, are put down are called “of inherence”, because they are equivalent to propositions of inherence. For I may say either “It is true that Socrates is a man” or “Socrates is a man”, [and] it is the same, because these propositions are equivalent. Further, these are equivalent: “It is false that Socrates is a man” and “Socrates is not a man”. And because a mode is sometimes preposed, sometimes interposed, and sometimes postposed to the appellation of the dictum, we should inquire what the appellation of the dictum is; but first [we should inquire] what a dictum is.