Russell describes the theory of reference in his work 'On Denoting' which consists of the following components among others.

1. Logic
2. Grammar
3. Function of language
4. Description

He used two types of analyses for proving his 'reference' unit. His theory is a prototype of logical arguments in analytic philosophy. At the commencement, he expresses that language is the method of philosophy by making the distinction between two types of knowledge. They are as follows:

1. Knowledge by acquaintance
2. Knowledge by description

In 'knowledge by acquaintance', meaning of an expression is determined independent of its truth condition. But in case of 'knowledge by description' we search for truth condition of the sentence. Knowledge by description expresses 'to know' is to know something is the case and 'to know something is the case' implies 'to have the knowledge of the case'. For example, this table is brown. Considering the example if we hold the expression 'to know', then it conveys we know the meanings of all the constituent words of the sentence 'brown', table', 'this' and 'is'. But when we consider the second unit, i.e. 'to know something is the case', it expresses a fact of the world. As a result, we determine the truth or falsity of the fact. Thus, in order to know the meaning of a sentence we need to analyze it. In this context, Russell said that 'knowledge by acquaintance' is the result of direct perception and 'knowledge by description' is not so. But both are concerned with the acquisition of the knowledge of objects or states of affairs of the world. He enunciated that sense organs are rudimentary for 'acquaintance', but we can't consider those as the sole means to acquire the knowledge about the objects or facts of the world. So he added two more principles into it. These are; 'memory' and 'introspection'.