Frege states that to know the sense of a proposition means to know the conditions where it is to be applied. Hence, we know its applicability to the world. He used the philosophical terms 'mode of presentation' and 'mode of applicability' to explain this point. Sense of a proposition depends on its mode of presentation, whereas reference of a proposition relies on its mode of applicability. These two modes prone to state that to know the sense of a proposition means to know how to express the proposition, and to know how to express the proposition means to know the conditions where it is to be applied. Thus we arrive at the sense of a given proposition.
Sense is logically prior to reference. It is the sense that leads us to towards reference. It is so because unless we know the sense of a proposition, we cannot know what it expresses. Thus, sense assists us to identify the referent of an object or a concept. A pertinent question is raised here, how does the sense of a sentence determine the reference?
Sense Determination and Reference
Sense is a passage through which we reach reference. To quote Dummett in this context: "the sense of an expression is what we know when we understand it, and what we know when we understand it is something like an ideal procedure for determining its reference" (Perry, 1977, 475). Frege's notion of 'sense' is applied to all including 'proper names'. Now the question before us is, "Do proper names have sense?" Frege's reply to this question is that all proper names have a particular 'sense', but they differ only in 'opinions'. Though opinions differ from person to person on a particular object yet the sense is invariant to all. For example, in order to explain a proper name 'Aristotle' there can be different descriptions, such as "the pupil of Plato", "the teacher of Alexander the great", "the author of Nichomachean Ethics", yet the sense of the term 'Aristotle' remains same for all those who are using different descriptions. It is so because all of them understand the proper name 'Aristotle' and do communicate in the language.
Frege's notion of sense is analyzed in the following passage which he had written to his friend Philip Jourdain in 1914:
"Suppose an explorer is traveling in an unexplained country and sees a high snow capped mountain on the northern horizon. By making inquires among the natives he learns that its name is 'Afla'. By detecting it from different parts he determines its position as exactly as possible, enters it in a map, and writes in his diary: 'Afla' is at least 5,000 meters high.' Another explorer sees a snow capped mountain on the southern horizon and learns that it is called Ateb. He enters it on his map under that name. So, both of them enter the mountain on their respective maps under different names. Later comparison shows that both explorers saw the same mountain. Here, the geographical knowledge of that particular mountain which is presented in different names is same. Thus, the thought expressed in the proposition 'Ateb is Afla' would have to coincide with the proposition 'Ateb is Ateb' and 'Afla is Afla'. Before exploring 'Ateb is same as Afla', it is certainly marked that 'Ateb is Afla' is not the same thing as the content of proposition 'Ateb is Ateb'. If we correspond to the name 'Ateb' as part of our thought, it refers to one object called snowcapped mountain. In the similar fashion, if we refer to the name 'Afla', it corresponds to the same object as snow capped mountain. Thus it is resulted that, the reference for both the names, Afla and Ateb is same whereas their sense differs from each other"5 (Frege, 1997, 320-1).
From the above passage it follows that though these two expressions 'Ateb is Ateb' and 'Ateb is Afla' have different sense, yet both of them refer to one and the same object.
| 5 | This passage presented in a precise form is borrowed from Frege, G. (1997). The Frege Reader. In M. Beaney (ed.), Oxford: Blackwell Publication. See, Noonan,H.W. (2001). Frege: A Critical Introduction. Cambridge: Polity Press, 169-170. |