Definition theory in al-Fârâbî and its relationship with demonstration theory

Al-Fârâbî was a peripatetic philosopher known as the "Second Teacher" after Aristotle, the "First Teacher", the systematizer of logic, for restoring logic to its rightful value and making demonstration the basis of philosophy once again. Al-Fârâbî shaped Islamic philosophy and became a standard for those who came after him. In his Kitâb al-Burhân, al-Fârâbî, who placed demonstration at the foundation of philosophy, dealt extensively with the theory of definition and emphasized the relationship between demonstration and the theory of definition. The theory of definition, which until Avicenna had been treated together with demonstration, was separated from demonstration after Avicenna and analyzed in the section on concepts in logic. This change in question caused serious transformations beyond a simple change of position. "Târif" is defined as "that which is the cause of the conception of a thing and its distinction". Definition is divided into two categories: substantive (definition) and correlative (description). A substantive definition is defined as "a word that indicates the essence of a thing. In a substantive definition, the constituent elements of a thing are brought together to form a phrase that is equivalent to that thing in terms of being a predicate. The questions of how this phrase, which becomes the representative of the relevant thing in the mind, is formed, how predicates are obtained, and how the congruence between the definition and the defined is ensured are investigated within the framework of the theory of definition. Burhân is a syllogism formed from certain (yakînî) premises. The aim of the demonstration is to arrive at certain conclusions by using the certain premises obtained. Since the conclusions reached by the demonstration will also be certain, these conclusions will be the premises for the subsequent demonstrations, and this process will continue continuously, expanding the field of knowledge. Each syllogism is composed of three terms: major, minor, and intermediate, and the syllogism works by relating these three parts to each other. The question of how the definitions of these three terms are known in the first place (before the demonstration is established) is closely related to the theory of definition. To increase knowledge, one moves from the known to the unknown. Therefore, the meanings and definitions of the terms used in the demonstration must be known beforehand. The unknown (the result of the demonstration, the new known) that is revealed on the basis of the known can also be the meaning or definition of something else. Thus, there is a relationship based on mutual interaction between definition and demonstration. This relationship, which manifests itself in the closeness of the questions "What is it?" and "Why?", can be clearly understood only when the theory of definition and the theory of demonstration are considered together. Both definitions and demonstrations produce results with certainty only to the extent of the certainty of the content used. The theory of definition and the theory of demonstration have a working scheme that is independent of content and has universal certainty. If the relevant schemes are identified and presented as immutable constants, logic will undoubtedly fulfill its task of being a criterion/measure.