A Critical Introduction to Frege’s Notions of Sense, Reference and the Thought
Sense and Reference, Descriptions and Names
According to Frege, the names ‘Tony Blair’ and ‘Tony Boy’ do not have the same Fregean ‘sense’; but they do refer to the same thing. Proper names, according to Frege, do not have meanings.Names, therefore, are entirely determined by their referents. Think about the addition
2 + 2
and the number 4. The first addition has the same reference as the latter number – viz., 4. However, 2 + 2 and 4 do not have the same sense. If they didn’t have different senses then the equation 2 + 2 = 4 would not give us any new information. We may as well have written:
4 = 4.
In a sense
2 + 2 = 4
is identical to 4 = 4. However, because the former have different senses, then we can learn something from a mathematical statement of identity. If 2 + 2 were not equal or identical to 4, or if they did not have the same reference, then we could not say that 2 + 2 = 4. The left side of the equation only equals the right side because both sides have the same reference – viz., 4. The names ‘Tony Blair’ and ‘Tony Boy’ both have the same reference. However, they have different senses. Someone may know Tony Blair as ‘Tony Blair’ and not know that the guy who played the guitar who was called ‘Tony Boy’ is the very same person as Tony Blair. This must show that the two different names have different senses, but the same reference.
The important thing about the distinction between sense and reference is that it helps us make sense of the problems we encounter when the same object has different names. And because the same objects has different names, then these different names must also have different senses. Of course we now need to know what Frege meant by his term ‘sense’. The term ‘reference’ is fairly clear, but not the term ‘sense’ because this term is clearly not synonymous with the word ‘meaning’.
Sense and Reference, Identity and Predicative Statements
In the following, one sentence is an identity statement and the other is predicative:
The Morning Star is Venus = identity statement
The Morning Star is a planet = predicative statement
However, grammatically they look very much alike in construction. In both we have a subject followed by a predicate. However, in the first example we have two names that refer to the same object – Venus. These two names have the same reference but different senses. If the two names for the same object didn’t have different senses, then the sentence
The morning star is Venus
could not possibly give us new information about either Venus or the Morning Star. This statements can tell us something that we don’t already know, unlike the statement
The morning star is the morning star.
which is not informative. The second sentence, on the other hand, is a predicative statement. The concept [planet], or the predicate ‘is a planet’, is being applied to the subject, ‘The Morning Star’. Here we are being told something about the subject – that it is a planet. The other statements is telling us not something about the object’s attributes, but that two seemingly different objects are in fact the same object. The first sentence should be re-formulated, according to Frege, as:
The expressions ‘the Morning Star’ and ‘Venus’ refer to the same object.
Here it is made clear that the sentence is not a subject-predicate sentence, and neither is a predicate being applied to a subject. In essence, it has two subjects that both refer to the same object. The ‘is Venus’ of the first example is not actually being used predicatively, despite appearances.
Frege’s Attack on Psychologism: Does Mankind Have a Common Stock of Thoughts?
Frege claims that it is not true that certain words in one language are not translatable into another. He comments on the belief that
no word is ever taken in quite the same way by men who share the same language (1967).
Frege argues, however, that different words do have something in common, though not everything. He calls this the ‘sense’, in the case of words, and the ‘Thought’, in the case of sentences. He says that the same sense or Thought is shared between languages, even if it is ‘variously expressed’. It is the ‘expression’ that is different. An expression is an expression of something or it is about something. It is this thing that is the sense or Thought. Frege goes so far as to say that the
multiplicity of languages mankind has a common stock of thoughts.
Logical or philosophical analysis, according to Frege, is the discovery of the Thought within ‘various expressions’.
The belief that mankind, despite it many and varied languages, has its ‘common stock of thoughts’ is far too Platonistic for many philosophers. His position seems to discount the possibility that different communities or cultures cannot have markedly different experiences(see Haak, 1979). That is, if we already accept that experience is a prime determinant of language and meaning. For example, does every language have a word for ‘reference’, let alone access to the same sense for the word ‘reference’? Frege might have said that he is talking about the words that we do share. If we do share inter-translatable words, we do so because we all have access to the same senses of these words. This means that there will be inessential dissimilarities in the use of the same word, but, nevertheless, if we share the same sense of that word or sentence, then there should be not too much trouble in communication and translation.
It is because different people take words or sentences in different ways that Frege wanted to capture something about the sentence that remained invariant from person to person. Despite the flux of mental states that accompany our sentences, the Thoughts remained unchanged from man to man. Thus we could assure ourselves of objectivity when using these sentences. But what is it, again, that the sentences keep when they are variously expressed? We cannot simply say that it is the Thoughts unless we also say what the Thoughts are. What are their individuation conditions? Again, if we say:
It’s what the sentence expresses.
What is it, precisely, that is being expressed? Or:
It is something capable of being judged true or false.
What is this ‘something’ that can be judged true or false? Propositionalists are keen to tell us what propositions aren’t, but not too keen to tell us what they are. This is similar to the case of God. People describe God as ‘omnipotent’, ‘omniscient’, ‘benevolent’, etc., but they don’t as often tell us who or what is the subject or owner of these qualities. Similarly a Thought ‘can be true or false’, ‘it is what the expression expresses’, ‘it is a unit of information’, etc., but what is it that hasthese characteristics?
Thoughts, Senses and Sentences
Frege is correct to say that Thoughts must be expressions of ‘some thing’ or about ‘some thing’, but they are not the expressions of Thoughts or about Thoughts. Of course other semantic theories don’t work either. For example, the meaningof a word was once deemed to be the object it referred to, according to Frege’s near contemporary, J. S. Mill. And if truth-conditions are brought into the picture, at least we have a route into the empirical world. But truth-conditions are, in a sense, simply enlarged denotata. They do not in and of themselves tell us anything. What about word and sentence synonymy? Here, prima facie, it seems to be the case that we can never get outside language. In extreme cases, we commit the crime of linguistic idealism.
A Fregean Thought is the ‘sense’ of a sentence that can be used to make an assertion or to ask a question that is answerable by either ‘Yes’ or ‘No’. The contents of Thoughts can be true or false. Thoughts in this sense are logical or conceptual rather than a matter of individual psychology. Different individuals may share the same Thought, although they cannot share the same act of thinking.
If a Fregean Thought is the ‘sense’ of a sentence then it evidently follows that it is not the sentence itself. It is, if you like, contained within or expressed by the sentence, but is not equal to the sentence. It is the content of the sentence.People do not share the same acts of thinking. But they often do share the same sentence. And even when sentences vary in the attempt to express the same Thought, these variations are still sentential variations that need not depend on a Fregean Thought.
We can share concepts, but we can also share words. Does this automatically mean that concepts too do not depend on words? Of course the same concept can be expressed by different words or sets of words. But, as with propositions and Thoughts, we can invert this argument by saying that the same words can be expressed by different concepts. Why put concepts at the top of this particular hierarchy? Do we ever have wordless concepts floating around within our minds or in a Platonic world? We may of course have wordless mental images or even representations, but these are not concepts, although they may be used in order to individuate concepts. Concepts, as it were, say something or ascribe properties or features to those entities that fall under them. Mental images or Lockean ‘ideas’ can be taken as not saying anything at all.
What does it mean to say that Fregean Thoughts are ‘logical’? Thoughts are ‘logical’ in the way that logical connectives are logical. They are the tools we use to express things, but they are not the expressions themselves. We construct sentential expressions with the help of concepts and logical connectives, amongst other things.
The Fregean Thought, Its Reference and the True
It seems strange, prima facie, to say that a whole sentence can have its own reference. We could say here that Frege meant that every statement or expression contains a proposition. However, for one, ‘Thought’ is not synonymous with ‘proposition’. Two, it is not the case that only statements contain a Thought; sentences of all types do so, Frege argued - some sentences are not propositional or statemental. And, of course, we can translate sentences that are not themselves statements. This seems to show us that Thoughts are different from propositions. A proposition, in the tradition, is something that can either be true or false. The sentence ‘Shut that door’, on the other hand, cannot be either true or false, but it still contains a Fregean Thought.
Is the Thought of a sentence its ‘reference’ or ‘sense’? It would make things easy if we said that the reference of the whole sentence is the Thought contained in the sentence. But the reference is just the thing named and nothing more. Certain words and names have a sense as well as a reference, so how can the sentence refer to the Thought if it may be changed by the sentence’s individual different senses? Frege explains this by saying that we can change various words in the sentence for new words with the same reference. These new words may have different senses to the old ones. When we change the words with new words with the same reference but different senses, we also, in the process, change the Thought ‘contained’ in sentence. The Thought is as dependent on the senses of the words in the sentence as the references of the words in the sentence. We may have the following sentence
The Morning Star is a body illuminated by the sun.
changed into
The Evening Star is a body illuminated by the sun.
Clearly these two sentences have the same reference – viz., Venus. And they are both saying the same thing about Venus – viz. that it is a body illuminated by the sun? However, two names are used in the two sentences. These two names must have different senses even though they have the same reference. If a word or a set of words with different senses, but the same references, has been added to the sentence, then the Thought itself will change its nature, even though the sentence refers to the same things. The Thought contained in the sentence is changed when new words are added with different senses but the same references. If the Thought contained is changed by such substitutions, then it says something different because of the new senses involved.
Frege concludes that the Thought of a sentence is not that sentence’s reference, but its sense. Put simply, it is the sense of a sentence because if new words with different senses but the same references are substituted for the old words, then the whole Thought contained in the sentence changes too. To put it another way, the Thought depends just as much on the sense of the words in the sentence than the words’ references. The overall sense of a sentence matters to the Thought, as it were.
The Thought is Neither Linguistic Nor Mental
According to Frege, when I say
John is black.
I do not have an idea, image, picture or expression in my mind of John or of John being black - or anything for that matter. All that happens is that I give you
a definite and objective piece of information.
In other words, I
transmit a Thought or Proposition.
What is this Thought without any mental correlates? Can’t it both an objective piece of information and the cause or correlate of mental images, pictures, linguistic expressions, etc? Can we have the one without the others?
What is the nature of that ‘information’? What does Frege mean by ‘information’? Even if that information has some kind of non-linguistic or non-mental existence, it is still expressed via expressions of a conditional nature. We can accept a conceptual distinction between ‘information’, and the expressions of that information, but what is that information like without any expressions of it? Sure enough, the same units of ‘information’ can be expressed in different ways, but does that automatically mean that it has some kind of ontological existence separate from all contingent expressions? Perhaps it is linguistic expression instead that can be variously expressed. That is, E can become E¹ and E², rather than a piece of information or a Fregean Thought being expressed by E and E¹, etc.
If the ‘transmission’ of a Thought is always linguistic, perhaps we are wrong to emphasise the Thought’s independent existence from sentential expressions, or even that it exists at all. An expression can be variously expressed just as a Fregean Thought or a proposition can be variously expressed. And if that’s the case, why fall back on the reality of independent Thoughts at all? This means that the Thought has no existence when not sententially expressed, even though, again, we can quite happily accept that the Thought can be variously expressed.
If John is named ‘John’, and the colour black is called ‘black’, for various inter-subjective reasons, then perhaps so too must the Thought be inter-subjective and therefore mental in nature. Remember, the colour black is a sensation, and therefore mental. And John is only named ‘John’ according to public practice. So how can the sentence ‘John is black’ express a mind-independent Thought? All along we see that Thoughts cannot escape the mental as it expresses itself linguistically.
Just as I have emphasised the linguistic nature of the Thought, so too can I bring on board mental images and other mental phenomena as necessary correlates and accompaniments to Thoughts, or of the expression of Thoughts. Without mental imagery, etc., perhaps we could not even make sense of the locution ‘John is black’. Although there may be a state in the empirical or the Platonic world that is expressed by the sentence ‘John is black’, that state in the world cannot actually be said to be John’s state of being black, for reasons already given. There are things other than mental states and linguistic utterances, but none of these things on their own could be called ‘Thoughts’ or Fregean ‘information’. They may necessary, and even, perhaps, mind-independent, but the Thought or unit of information itself cannot be mind-independent. Again, the mind-independent parts, as it were, may be necessary, but they are not sufficient for the Thought or the unit of information, never mind its expression.
The True and the False as References of Sentences and Non-Existents
What Frege makes clear is that a sentencecan have a sense even if it has no reference, for pretty much the same reason that a word can have a sense and no reference. It must follow, according to Frege’s scheme, that we can use the names of non-existent entities and places and the sentence may still have a truth-value. Does ‘Odysseus’, for example, have a reference? Or is it used quasi-referentially without actually having a reference? But the statement
Pegasus used to fly over Athens.
does have a reference, and that is either the True or the False. This clearly means that even statements about non-existents, or statements about fictional characters, can have the reference the True or the False. Unlike Russell later, Frege wasn’t committed to clarifying the ‘logical grammar’ of statements like ‘Pegasus used to fly over Athens’. It seems very strange, prima facie, that the True or the False could be the reference of statements and sentences. What does Frege mean by this? It may follow that he sees these truth-values as abstract objects. Therefore the references concerned will have truth-values as their referents. Of course it may follow that a non-fictional true statement may have two types of reference. The references of the words contained, the reference of the whole sentence and the reference to the True.
Frege treated sentences or statements as proper names. Not only do proper names have a sense and a reference, but so too does the sentence. A declarative sentence declares that something is in fact the case. Therefore it will have as its reference either the True or the False. If that is the case, then it will also follow that all true statements will have the same reference – viz., the True. And the same will be the case with false sentences. There is no real explanation here of why a sentence is like or is a proper name, or how we can refer to the True or the False.
References and Further Reading
Frege, G. (1967) ‘The Thought: A Logical Inquiry’ in Philosophical Logic, ed. P.F. Strawson
(1984) Collected Papers on Mathematics, Logic and Philosophy, ed. B. McGuiness
Haak, S. (1979) ‘Descriptive and Revisionary Metaphysics’ in Philosophical Studies 35
