An Inquiry into the Logical Meaning of A priori and A posteriori Demonstrations

Demonstrations are divided into á priori and á posteriori, with the difference that in the former the middle term is a cause both physically as well as mentally whereas in the latter it is only a physical cause. Given in a priori demonstration the middle term is conditioned to be a cause of predication of major term to minor term (not a cause of the existence of the major term), a priori demonstration is divided into four categories all of which produce absolute and permanent certainty. A posteriori demonstrations are alsodivided into absolute and relative a posteriori demonstrations. The fact that they do not produce absolute permanent certainty does not lead us to say they are not demonstrations. The discussion presented here reveals that the division presented by al-FÁrÁbi and the definition MullÁ ÑadrÁ has provided for a priori demonstration is no longer acceptable. It also deals with matters concerning the meaning of a priori and a posteriori demonstrations, which are seldom touched. These issues include 1) the objections raised concerning some demonstrations and their relations with each other and the answers given to them, 2) the relation between the ‘middle term’ and ‘minor term’ in a priori demonstration, 3) the division of demonstrations into a a priori, a posteriori, absolute and relative demonstrations being intellectually quantified, and 4) MullÁ ÑadrÁ’s view concerning the reality of the ‘middle term’ in demonstration.