本文試图扼要地讲讲形式邏輯所讲的关于概念的知識对明确概念的作用。什么是概念?概念是人脑对客观事物的本质属性(本貭属性是能区别某一类事物和其他类事物的一組属性)的反映。例如,“平行四边形”这个概念就是平行四边形的本貭属性——“两组对边各相平行的四边形”的反映。概念有內涵和外延两方面。事物有个体和类。同类事物都有一些相同属性(包括本质属性)。概念的內涵是指概念所反映的事物的本貭属性,概念的外延是指概念所反映的全部事物。例如,“語言”这个概念的內涵是“交流思想的工具,社会斗爭和发展的工具”,它的外延則是各种語言。概念的內涵就是概念的涵义,概念的外延就是概念的适用 This article attempts to outline briefly the role of formal logic in explaining the concept of knowledge to the concept of definiteness. What is a concept? Concept is the human brain’s reflection of the essential attribute of the objective thing (this attribute is a group of attributes that can distinguish a certain kind of thing and other things). For example, the notion of “parallelogram” is the parallel property of the parallelogram - the “two sets of quadrilateral parallel to the sides”. The concept has both connotation and denotation. Things have individuals and classes. Similar things have some of the same attributes (including essential attributes). The concept of connotation refers to the concept of things reflected in the nature of the concept of extension is the concept of the concept of all things. For example, the connotation of the notion of “language” is “tools for the exchange of ideas, tools for social struggle and development”, and its extension is in various languages. The connotation of concept is the concept of concept, the concept of extension is the concept of application