Sense and reference
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The distinction between Sinn and Bedeutung (usually but not always translated sense and reference, respectively) was an innovation of the German philosopher and mathematician Gottlob Frege in his 1892 paper Über Sinn und Bedeutung (On Sense and Reference), which is still widely read today. According to Frege, sense and reference are two different aspects of the meaning of at least some kinds of linguistic expressions. (Frege applied it mainly to proper names and, to a lesser extent, sentences). Roughly, a term's reference is the object it refers to; its sense is the way in which it refers to that object; the thought that it expresses.
Though the distinction has its home in philosophy of language, it carries over into other areas of philosophy, including philosophy of mind, metaphysics, and metaethics.
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Motivation for and development of the distinction
Frege's distinction rejects a view put forward by John Stuart Mill, according to which a proper name has no meaning above and beyond the object to which it refers (its referent or reference). That is, the word "Aristotle" just means Aristotle, that person, and no more. It does not mean "The writer of De Caelo." Hence, the sentence Aristotle was Greek says only that that person was Greek. It does not say that the writer of De Caelo was Greek. That is, it permits that Aristotle might not have written De Caelo. More generally, for any given proposition about Aristotle, one can use the name without believing that proposition to be true of Aristotle.
Frege noted three problems with the view that a name's meaning is no more than its referent. First, on this account, if a and b are names of the same object, then the identity statement a = b must mean the same as a = a. Yet clearly the first can convey information in a way that the second cannot; that Samuel Clemens is Samuel Clemens is just trivial, but Samuel Clemens is Mark Twain is interesting. Why? Or, why is Cicero is Tully more significant than Cicero is Cicero? Second, on Mill's view, two beliefs about the same object, under whatever names, must mean the same thing. So Superman can fly must mean the same as Clark Kent can fly. But obviously someone (Lois Lane) can believe that one is true and the other is false, without being irrational. If they mean the same thing, then it is hard to see how she could: believing one would be believing the other. Third, on Mill's account empty names--names whose referents do not exist, hence which do not refer to anything--must be meaningless. But many sentences involving empty names seem perfectly meaningful. For example, we can understand "Batman wore a cape", and understand that it means something different from "Superman wore a cape"; so they seem to still have some kind of meaning.
Frege's distinction is meant to make sense of these three cases, especially the first two. He postulates that, in addition to its reference (Bedeutung), a proper name possesses what he calls a sense (Sinn), some aspect of the way its reference is thought of that can differ, even between two names that refer to the same object. The important difference between 'a' and 'b' is a "difference in the mode of presentation of that which is designated". The sense of an expression is thus just "that wherein the mode of presentation is contained". Thus, one can know both the names Mark Twain and Samuel Clemens without realizing that they are about the same object, because they "present it in different ways," that is, they have different senses. Likewise, what Lois Lane understands in the two cases has a different sense, and is thus a different thought, even though it is about the same object (Superman, i.e. Clark Kent) and is true in the same circumstances. Finally, empty terms are meaningful because they have senses but no references.
- The reference is the object that the expression refers to. For instance, the name "Mark Twain" refers to Mark Twain, i.e. Samuel Clemens, the man who lived in the U.S. and wrote satires. The name Samuel Clemens also refers to that man. Hence the two have the same reference.
- The sense is the "cognitive significance" or "mode of presentation" of the referent. Frege also says that the sense "determines" the reference of an expression. There are two major interpretations of these claims:
- (1) A sense is equivalent to an identifying description. For example, the name "Mark Twain" might just mean "The man who wrote Tom Sawyer", and Samuel Clemens might mean "The eldest son of John and Jane Clemens". Thus the reference is "determined" as whatever fits the description.
- (2) A sense is not equivalent to a description, perhaps not to any expression; rather a sense is just whatever difference there is between a person's understading of two terms that could explain his failure to realize that they have the same reference. Here, sense "determines" reference only in that the relation between senses and references is never one-many; each sense is attached to a unique reference.
In either case, Frege expressly did not mean that the sense of a name was merely whatever ideas a user of the word associated with it. Because they figure into the meanings of terms in a public language and can be communicated, senses must be objective.
Frege uses an example with a, b, and c as the three lines each of which pass through one vertex of a triangle and the medians of the opposite side:
[t]he point of intersection of a and b is then the same as the point of intersection of b and c. So we have different designations for the same point, and these names ('point of intersection of a and b', 'point of intersection of b and c') likewise indicate the mode of presentation; and hence the statement contains actual knowledgeGottlob Frege, Über Sinn und Bedeutung
While Frege initially speaks of sense just as whatever solves the first two of these problems, he eventually makes gestures toward the idea that the sense of a proper name is a description believed to be uniquely satisfied by its referent (which would put him close to agreement with Russell's Theory of Descriptions; see below). Subsequent philosophy of language in the twentieth century (most famously by Kripke) has shown that this move is not innocuous, and it is now disputed to what degree this doctrine should be attributed to Frege. Some scholars,( e.g., Gareth Evans, John McDowell) have claimed that Frege's treatment of the third problem is inconsistent, and that without the need for "senses without references" there is no grounds for attributing a "descriptivist" (i.e. Russellian) view to Frege. But the descriptivist view was taken for granted throughout much of the twentieth century, and is probably still the "orthodox view."
Frege also examines (and rejects) the view that identity claims actually express relations between linguistic expressions . In this Template:Ref view, the claim a = b is about the expression 'a' and the expression 'b'. The sentence a = b says: The names a and b denote the same object. This view, Frege says, seems to misrepresent what we mean when we say a = b. First, we seem not to be talking about the expressions, but about the objects. Again, claims like a = b themselves can truly convey important knowledge which is not about words.
Terminology
Sense and reference (Sinn and Bedeutung)
Broadly speaking, the reference (or referent) of a proper name is the object it means or indicates. The sense of a proper name is whatever meaning it has, when there is no object to be indicated.
What this article has called sense and reference are what Frege calls Sinn and Bedeutung, respectively, in the original German. Sometimes the pair of terms is translated as sense and meaning or as sense and nominatum. The precise meaning of these terms can vary quite significantly from writer to writer, so some caution is due.
For Sinn, writers have used the terms sense, meaning, intension, connotation, and content.
For Bedeutung, writers have used the terms reference, referent, meaning extension, denotation, nominatum, and designatum.
Note that (confusingly) each expression has been translated as meaning by someone.
An expression's relation to sense or reference
Terminology has also been applied to capture the relation between
- an expression and its sense
- an expression and its reference
Frege is typically translated as saying that an expression "expresses its sense" and "stands for or designates its reference". Yet earlier in the essay he offers another verb, refers, writing of "that to which the sign refers, which may be called the reference of the sign". Since then writers have variously said that an expression stands for, designates, refers to, or denotes its reference. We can also say that an expression picks out its reference, or (alternatively) that the sense of an expression is what picks out its reference.
Sense without reference
One application Frege saw for the distinction concerns what are called nonreferring, nondenoting, or empty, expressions. These expressions do not have a reference, for example "the greatest integer" Template:Ref. Since there is not a greatest integer, the expression doesn't refer to anything. But it seems perfectly meaningful, since we seem to understand claims like "The greatest integer is larger than one million". Employing the sense-reference distinction, we can say that the expression has a sense but lacks a reference.
Another example is Odysseus. Since he is a fictional character, the name Odysseus does not appear to mean anyone at all; yet sentences like "Odysseus was set down on the beach at Ithaca" are meaningful, in that they can be true or false. If a sentence's meaning is a function of the meanings of its partsTemplate:Ref, then parts of the sentence, such as Odysseus, seemingly do have meaning.
Whether this solution works, and whether it was even seriously intended by Frege, is disputed. In order for it to be work, it must be possible for a term to have a sense without a reference, and this requires that sense cannot be defined simply as the mode of presentation of the reference, since sometimes there is no reference being presented. Thus the view that the sense-reference distinction solves the problem of empty names encourages the view that a sense is an individuating description (which could be understood with or without a reference satisfying it). This makes a sense equivalent to a Russellian description (see below), and makes Frege's position "descriptivist", leaving it prey to a number of difficulties raised against that view. Other philosophers have argued that Frege is not a descriptivist, and hence that the sense-reference distinction does not solve the problem of fictional names. Proponents of this view often claim that sentences using empty names do not in fact express propositions, hence are not literally meaningful, despite appearances. They face the difficulty of explaining the apparent meaningfulness of sentences using the word Odysseus. On one view, fictional names merely pretend to express propositions. Our understanding of sentences about Odysseus consists then in our "playing along" (see Gareth Evans, Saul Kripke).
Frege and Russell
Propositions and senses
Bertrand Russell famously rejected Frege's sense-reference distinction, though there is some question as to how clearly he understood it. One possibility is that the two were misinterpreting and arguing past one another: Frege talks about (for example) sentences, which have both a sense (a proposition) and a reference (a truth value); Russell on the other hand deals directly with propositions, but construes these not as abstract para-linguistic items but as tuples, or sets, of objects and concepts.
For Russell, sense is wholly semantic. Reference by contrast is intimately (and puzzlingly) connected with the named object. Mont Blanc is the referent of the name "Mont Blanc." Frege argues that the thought "Mont Blanc 'with its snowfields'" cannot be a component of the thought that "Mont Blanc is more than 4,000 metres high"Template:Ref. If the same expression "Mont Blanc" is in both sentences then there is something common to each thought, and therefore something corresponding to the name "Mont Blanc." This common element, which cannot be the referent, must be the meaning or "sense."
Senses and descriptions
Russell held the view that most of the apparent proper names in English are in fact "disguised definite descriptions. So "Aristotle" is understood as "The pupil of Plato and teacher of Alexander", or by some other unique description. Although Russell explicitly rejected Frege's notion of sense, he rejected it just for proper names. But Russell also had the idiosyncratic view (not evident in the Mount Blanc example) that most of the "proper names" in English are not names at all, but descriptions in disguise. Possibly the only real proper names were demonstratives pronouns like this and that (directed at an object that can be immediately perceived). So in fact if Frege's view was "descriptivist", then he effectively agrees with Russell on most of the apparent "proper names" of ordinary language: Frege thinks that "Aristotle" is a name, with a sense, which is equivalent to some description. Russell thinks that Aristotle is not really a name, but is (in disguised form) just such a description.
Thus for most of the twentieth century the "Frege-Russell" descriptivist view was taken as something of an orthodoxy. In Saul Kripke's famous Naming and Necessity lectures, which largely turned the tide against descriptivism, he treats both Russell and Frege as opposed to Mill's view in the same way. Thus Kripke's argument that names are not equivalent to descriptions was widely construed as the view that names do not have senses; or as a rejection of the sense-reference distinction. (Tellingly, all of the three problems the distinction aimed to solve have subsequently re-emerged as important problems in the philosophy of language.)
This reading of Frege has been rejected by many scholars, most strongly by Gareth Evans in The Varieties of Reference and by John McDowell in "The Sense and Reference of a Proper Name", following lines developed by Michael Dummett. Dummett argues that Frege's notion of sense should not be equated with a description. Evans further developed this line, arguing that a sense without a referent was not possible. He and McDowell both take the line that Frege's discussion of empty names, and of the idea of sense without reference, are inconsistent, and that his apparent endorsement of descriptivism rests only on a small number of imprecise and perhaps offhand remarks. And both point to the power that the sense-reference distinction 'does have (i.e., to solve at least the first two problems), even if it is not given a descriptivist reading.
Relation to connotation and denotation
The sense-reference distinction is commonly confused with that between connotation and denotation, which predates Frege and is famously interpreted by Mill. This distinction is applied mainly to words (particularly predicates) expressing properties (e.g., red, dog, bachelor), rather than naming individuals, so the difference between the two distinctions can be hard to see. The connotation of a predicate is the concept it expresses, or more often, the set of properties that determine whether an individual falls under it. The denotation of a concept is the actual collection of entities that do fall under it. Thus the connotation of bachelor is perhaps "unmarried adult male human" and its denotation is all the bachelors in the world.
Under a descriptivist reading of Frege, sense and reference are probably the same as connotation and denotation.
Under a non-descriptivist reading, they are probably not. It is always possible to have a connotation without a denotation, which may not be the case with sense and reference. A given sense always determines the same reference, which might not be the case with connotation and denotation. Most clearly, a single concept--which by definition has only one connotation and denotation (at a time), might be expressed by terms having different senses. For example, "cat" and "feline" have precisely the same connotation (member of the Felidae family of carnivorous mammals), and obviously the same denotation (all the cats; that is, all the felines), but it is perfectly intelligible that someone should fail to realize that cat and feline mean the same--perhaps they have only heard one word applied to housecats, the other two tigers and lions. In that case, the words have different senses.
See also
Footnotes
- Template:NoteAlso called the metalinguistic view. Frege had held to this view previously, and is worked out in his book Begriffsschrift. In addition, Donald Davidson offers a similar view, not of names but of quotation and indirect discourse.
- Template:NoteFrege's example is "the least rapidly convergent series", and there is always "the present King of France")
- Template:NoteSee Semantic composition
- Template:NoteThis example is from a letter to Russell.