Did the medieval philosophers admit the identity principle as prior to the principle of non-contradiction?

Ana Rieger Schmidt

doi:10.15448/1984-6746.2018.3.28846

Abstract

The present article deals with the not very common opinion among medieval philosophers according to which the identity principle (ens est ens) is the true first principle, undermining the primacy of the principle of non-contradiction. Following a refutation of this position in the logical work of the Franciscan Geraldus Odonis, we intend to investigate its target as well as other cases of the same dispute in 14th century authors: Antoine Andre, John of Buridan, John of Baconthorpe and Nicolas of Autrecourt. We defend that Odonis presents a successful response to this position.

Highlights

Resumo: Este artigo aborda uma opinião pouco comum entre os filósofos medievais, segundo a qual o princípio de identidade é o verdadeiro primeiro princípio, enfraquecendo a primazia do princípio de não-contradição
Medieval philosophers and theologians inherit a principle of Aristotelian origin that expresses the limits of meaning and consists in the first certain knowledge
Aristotle believes that opponents of the principle of non-contradiction (PNC) can be convinced otherwise if we show them the difficulties involved in refusing the PNC

Summary

Formal primacy and cognitive primacy

We find in Odonis treatment of the primacy of first principles a twofold distinction: we can consider the principles cognitive primacy or their formal primacy. These considerations provide the key elements to answer to the objection according to which the proposition "ens est ens" would be first to the principles of non-contradiction and excluded middle Since it has a simpler formulation and the predicate is immediately contained in the subject (they are identical), it should be concluded that this is the true first principle. According to Odonis, the determination implied in the copula decides its primacy: the copula presented in the proposition 'ens est ens' is more determined that the disjunction 'esse vel non esse' or the conjunction 'non esse and non-esse' For this reason, the predicate of the principles of noncontradiction and excluded middle apply to all that can be a subject in a proposition without positing it. The status first principle remains reserved for the two Aristotelian principles

The identity principle in Antoine Andre

Conclusion