The Relational Logic of Franciscus Toletus and Petrus Fonseca

Petr Dvořák

doi:10.35765/forphil.2009.1401.06

Abstract

The well-known Ratio Studiorum of 1599 states that logical instruction should follow F. Toletus (Toledo) or P. Fonseca. The latter authored the famous Institutionum Dialecticarum Libri Octo (1564), the former a similar manual, Introductio in Dialecticam Aristotelis (1561). As is often observed, the contrast between the Aristotelian and present symbolic logics is perhaps most striking in their analysis of relational statements. Both authors recognize the relational logical form as independent from the traditional subject-predicate form and see the need to recognize relational inferential rules. They differ in their specific rules, however, so neither of the authors has captured the system of relational syllogism in its entirety.

Highlights

The well-known Ratio Studiorum of 1599 states that logical instruction should follow F
In the third decade after its foundation, the early Society produced two outstanding textbooks of the discipline, those of Franciscus Toletus (Toledo) and Petrus Fonseca, which found their way to students in Bohemia during the 1570s1 and which gained official recognition through the Ratio Studiorum of 1599
I would like to introduce the two authors and their logical work, compare their introductions to logic and, analyze a particular aspect which is present in both of them, i.e. the logic of relational statements. The latter topic is especially interesting from today’s perspective, for it is the logical analysis of relational statements that produced the greatest dissatisfaction with traditional logic as incapable of providing a logically satisfying treatment and the impetus to look for an alternative, giving rise to mathematical logic as we know it today

Summary

Introduction

The well-known Ratio Studiorum of 1599 states that logical instruction should follow F. The latter topic is especially interesting from today’s perspective, for it is the logical analysis of relational statements that produced the greatest dissatisfaction with traditional logic as incapable of providing a logically satisfying treatment and the impetus to look for an alternative, giving rise to mathematical logic as we know it today.

Results

Conclusion