A revised dating of the eclipse

The view that the insights and developments of medieval logic were eclipsed during the fifteenth century by a humanist, rhetorically-oriented logic has long been popular, but it needs considerable revision and modification. In what follows I shall first give a brief account of what happened to the writing, teaching, and publication of logical works in the medieval style, by which I mean those which discuss such topics as consequences, in-solubles, exponibles, and supposition. I shall then examine in more detail what was actually said about certain medieval doctrines in the late fifteenth and sixteenth centuries in order to indicate both where logicians of the period had something new to contribute, and where there were departures from medieval doctrines which cannot be attributed to new logical insight. My conclusion will be that medieval logic as a living tradition did largely disappear, but that the eclipse dates from about 1530 (in so far as a specific date can ever sensibly be offered) rather than the mid fifteenth century.

Fifteenth-century logicians

After the death of Paul of Venice in 1429, the fifteenth century did not give rise to much important logical writing. There were various logicians in Italy who deserve mention for their contributions to logic in the medieval style, including Domenico Bianchelli (Menghus Blanchellus Faventinus), who wrote a long commentary on Paul of Venice's Logica parva; Paul of Pergula, who wrote on Ralph Strode's Consequentiae as well as producing his own Logica; and Gaetano di Thiene, who wrote on Strode, William Heytesbury, and Richard Ferrybridge.