Abstract

Knowledge means the presence of the known before the knower, and it is either presential or acquired. Presential knowledge means the presence of the known's existence before the knower, such as man's knowledge of himself.Acquired knowledge means the presence of the known form before the knower, such as man's knowledge of external objects. Here, what is directly present before the knower is a concept of the known, and what is known by essence is that very concept, and the external object is known by accident.Logic is the collection of principles of thought. Observing such principles, which are totally in the domain of acquired knowledge, protects the mind against errors in the process of thinking.Muslim logicians, following Farabi, divide man's knowledge into two types: concept and judgment; accordingly, they divide the science of logic into two parts: one part deals with the issues related to concept and the other with issues related to judgment. The two types represent the primary division of acquired knowledge into its different kinds.On second division, acquired knowledge, i.e., the very concept and judgment, is divided into evident and theoretical types. Evident knowledge is known by itself and is needless of idea and thought. Theoretical knowledge is not known by essence and, in order to be known to the mind, it requires thinking. It is here that the science of logic comes of use in acquiring the theories from evident things or other theories.What was said about the primary division of acquired knowledge into concept and judgment and its secondary division into evident and theoretical types is acceptable to most Muslim logicians except for Fakhr al-Din Razi. He does not believe in theoretical concept; however, no one agrees with his views.