Abstract

The syllogism that its major premise is a conjunctive proposition is called concomitance syllogism. This sort of syllogism is valid in two forms of "affirming the antecedent" and "denying the consequent", and is invalid in all others forms. The concomitance syllogism have several modes in Holy Quran: In some cases the conditions of the syllogism are fully observed but because of clarity their preliminaries or their results have not been presented, and the syllogism is idiomatically shortened. But in some other cases it seems the conditions for the concomitance syllogism have not been regarded and "denying the antecedent" and "affirming the consequent" are used for the conclusion.In this research, some of the most important syllogisms in Holy Quran are reviewed and in cases where it seems that the conditions of the syllogism are not concerned, their reason will be considered, and using the content of Holy Quran and the general rules of reasoning such as the "cohesion of hypotheticals ", this sort of syllogisms will be converted to a validated syllogism. So, it is proved that the general rules of thinking have been respected in Quran as a book for human guidance which has been revealed in human language.