Around 1892, Gottlob Frege revised his semantics. This revision solves a number of problems that the earlier, monistic account is not able to handle without further expansion. For Frege, not only proper names but also concepts, words and relational expressions possess sense and significance. Their significance then is a concept or relation, not an object, and their sense consists in a logical thought component that contains the necessary and sufficient conditions for an object to fall under the concept or stand in relation to another object. Frege's idea is based on the dependence of truth-values on arguments and functions. The non-existence of an object corresponding to a specific sense amounts to the lack of an argument for the functional part of the sentence, and therefore leads to the lack of a value for that function in this case.
THE CONCEPT OF SENSE AND SIGNIFICANCE
Gottlob Frege is concerned with the question of how the sense (or mode of presentation) of a sign is related to the meaning which is expressed by the sign. According to him, each expression has a sense which contains a unique way in which the object that the expression…show more content… But this means that -- since the truth-value of the entire sentence functionally depends on the significance of each part -- what the embedded part stands for cannot be a truth-value. Rather, Frege concludes that in the case of indirect speech and belief ascriptions, embedded sentences take on their original sense – the thought they normally express – as an indirect significance. Thus, while the thought they normally express is their sense in direct speech, it becomes their significance in indirect