Frege states that 'sense' of an expression is not associated with our psychology because psychology is a mental phenomenon which varies from speaker to speaker and speaker to hearer. But it is something which is objective, eternal, and exists timelessly. For example, it is true that "Water flows down" and would have been true even if there had been no being on the earth. Thus what is true is a thought, and a thought is the sense of a proposition.

Further, Frege states that sense is intrinsically, inherently, and logically connected to a proposition. By giving an analogy he states that sense is the immaterial garment of material cloth of a proposition.⁶ Thus sense is objective, eternal and at the same time communicable. He expresses that the sense of a proposition is same as the thought of a proposition.⁷ Since every sentence is embedded with sense, therefore all sentences must have thoughts. As a result, all sentences can be judged as either true or false. In other words, all sentences can have the truth-value.

There are cases where different sentences of ordinary language have same truth-value but differ in their meanings. For example,

1. The author of Nechomachean Ethics
2. The pupil of Plato

These two expressions have different meanings but they refer to one and the same individual 'Aristotle'. So these two expressions have the same referent. Therefore, they have the same truth-value. It is so because for Frege reference of a sentence is same as truth-value of that sentence. Further, he suggests that two different sentences have same truth-value if they refer to one and the same object.

As it has been stated earlier that every sentence has a sense and from sense we can go to the reference. It implies that we refer to the object what the sentence is stating about. In this context Dummett points out that sense is key to our understanding of sentences and helps to determine truth-value of sentences. Further, he adds that what we know when we understand a proposition is something like an ideal procedure for determining its reference. There are two sorts of reference. They are as follows:

1. Word-reference
2. Sentence-reference

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6	The Idea is expressed in Frege,G. (1977). Thoughts. In P.T. Geach (ed.), Logical Investigations, Oxford: Basil Blackwell Publication, pp.1-30.
7	See, 'More about Thoughts', In M. Dummett (1991a). Frege and Other Philosophers. Oxford: Clarendon Press.