While primarily devoted to modern formal logic, contains much on term and medieval logic.

Supposition theory was a branch of medieval logic that was probably aimed at giving accounts of issues similar to modern accounts of reference, plurality, tense, and modality, within an Aristotelian context.

These 24 possible permutations include the 19 syllogistic forms deemed valid in Aristotelian and medieval logic.

Systematically, it resembles other works of medieval logic, organised under the basic headings of the Aristotelian Predicables, Categories, terms, propositions, and syllogisms.

Hughes' other special interest was in medieval philosophical logic, where his main projects were the preparation of philosophical commentaries on Latin manuscripts of John Buridan and Paul of Venice, as well as English translations of the originals.

It appears in William of Sherwood's Introduction to Logic and is given the name arbor Porphyrii in the most popular medieval logic, Peter of Spain's Summulae Logicales.

In medieval logic and epistemology, this is a sign in the mind that naturally represents a thing.

"The theory of supposition with the associated theories of copulatio (sign-capacity of adjectival terms), ampliatio (widening of referential domain), and distributio constitute one of the most original achievements of Western medieval logic".

This modern moodiness has its value, though the moderns overrate it; just as medieval logic had its value, though it was overrated in the later Middle Ages.

"That's a fine specimen of medieval logic."