gottlob frege's analysis of language - class notes by bernard weiss

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  • 8/9/2019 Gottlob Frege's analysis of language - class notes by Bernard Weiss

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    The Fregean Background

    (i) Freges Analysis of Language

    At its simplest, our task is to analyse sentences such as Fred is red; Gertrude is

    loud; Everest is high. How do we explain the fact that these sentences mean whatthey do on the basis of what the component words mean?

    Frege, a mathematician interested in the foundations of mathematics, comes at

    this problem from a distinctly mathematical perspective. So lets set aside for the

    moment the question about language and take a simple mathematical function, say,

    the function of adding 2. Heres a table of the results of applying this function to a

    series of numbers:

    x x+2

    1 3

    2 4

    3 5

    5 7

    OK this is all easy enough. We obviously understand the function and know what the

    result of applying the function to any number is. Freges question concerns the nature

    of the function and how we are to represent it. It is tempting to represent the function,

    as we did in the table, by saying it is the function x+2. This isnt entirely wrong but is

    apt to be misunderstood. If x simply designates an indeterminate/imprecise number

    then so to does x+2; it doesnt represent the function itself. In order to get at the

    function we have to see what is common between the numbers in the right handcolumn. That is we want to express the pattern we can see in:

    x x+2

    1 1+2

    2 2+2

    3 3+2

    5 5+2

    That is we want to see the numbers on the right as arising from adding two to thenumbers on the left. The function is something which takes each of the numbers on

    the right to the appropriate number on the left. So it is something which gives the

    numbers on the right when we replace the x in x+2 by the numbers on the left. So

    the expression for the function should be thought of as something essentially

    incomplete since it yields expressions for certain numbers when other numbers are

    placed in a specified position. So the expression for the function should be something

    which makes this incompleteness explicit, viz.,

    ( )+2

    Importantly, Frege thinks that since we must represent the function to ourselves in thisway we must think of the function itself as being essentially incomplete.

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    So, to sum this up, a function is an incomplete entity which takes numbers (certain

    objects) to other numbers (other objects). The expression for a function should make

    its incompleteness explicit; we need, that is, to indicate the functions argument place

    or places.

    Examples of functions:

    ( ).3+5; ( ).( ); ( )2-67; ( ); ( )+ { }

    (Here the different styles of brackets indicate that these gaps may be completed by

    using different numbers.)

    In general whenever we have a (complex) expression for a number we can extract

    some of the symbols for numbers and arrive at a function.

    E.g., we may have 5.3+52 from which we might extract the symbol 5 to arrive at

    the following expression for a function: ( ).3+( )2. Or we might only extract onesymbol 5 to arrive at: 5.3+( )2. We might also extract the symbol 5 and 3 to

    arrive at: ( ).{ }+ ( )2.

    As long as remember how to interpret the x, i.e., as indicating a gap, not as

    indicating an indeterminate number, then we can replace the brackets by xs and ys.

    Note that the function 2.(x+1)-2.x, whose value is always 2 no matter what we

    substitute for x must still be sharply distinguished from the number 2 itself: the one is

    a function the other a number, that is, a kind of object.

    Consider this somewhat different case. Take the arithmetical expression 2+3=5, if

    we extract the symbol 3 then what we should have left according to Frege is an

    expression for a function. And obviously we can substitute names for other numbers

    in the place occupied by 3 to get:

    x 2+x=5

    1 2+1=5

    2 2+2=5

    3 2+3=5

    5 2+5=5

    But the expressions on the right are complete, so, according to Frege, they should be

    names. But what do they name? Clearly they differ from expressions such as 2+3 in

    that they can be true or false (all but the third is false). But Frege treats them like

    these other expressions: he simply says that they name Truth and Falsity. So the

    function 2+x=5 is a function which takes numbers to truth-values. Any function

    whose values are only the two truth-values is said by Frege to be a concept.

    Natural Language

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    Lets try to apply this framework to natural language, as Frege did. Take our sentence

    Fred is red if we take the name Fred from this sentence were left with x is red.

    So this according to Frege is an expression for a function, specifically, a concept: it is

    a concept which takes objects, including Fred to truth-values.

    Are there functions which arent concepts in natural language? Indeed there are.Consider this way of talking of South Africa: The homeland of Nelson Mandela.

    Here we have an expression for a function, namely, The homeland of x which takes

    people (among other things) to countries. The example can obviously be multiplied.

    Lets think now about logical vocabulary. Take, for example, the conjunction The

    weather is foul and I am tired of getting soaked. We can extract the two sentences to

    get an expression for a concept: x and y. The role of this concept is to take truth-

    values to truth-values. We might sum this up as follows:

    x y x and y

    True True True

    True False False

    False True False

    False False False

    Here we can ignore which particular sentences we replace x and y by since all those

    sentences simply function as names for one or other of the two truth values. So we

    can capture the meaning of x and y completely by the above table which exhausts

    the possible combinations of truth-values. Conjunction is thus an example of a truth

    function and we arrive at whats now commonly called the truth functional definitionof the sentential connectives (x and y; x or y; not x; and if x then y).

    Finally lets consider the sentence All men are mortal. Our aim is to work out what

    sort of expression all is. Lets start though with men and mortal These have the

    same meaning here as in Socrates is a man and Socrates is mortal respectively. (If

    they didnt have the same meaning then the syllogismAll men are mortal. Socrates

    is a man. Therefore, Socrates is mortal.would commit the fallacy of equivocation,

    which it clearly does not.) That is we have two functions x is a man and x is

    mortal. So the form of the sentence is better represented as For all x, if x is a man

    then x is mortal. And here we apply the function For all x to the complex function

    if x is a man then x is mortal; that is, we have a function of functions.

    So, For all x, Fx says of the concept F that it is satisfied by every object. There is

    an x such that Fx says of the concept F that it has at least one instance.

    What weve been given is an account of how the semantic value of a complex

    expression is determined by the semantic values of its parts. The semantic value of an

    expression is an item in the world with which it is correlated, which it refers to or

    denotes. So the semantic value of a name is an object, the semantic value of a

    functional expression is a function and the semantic value of a sentence is a truth-

    value.

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    We need to say a little more about functions. A function, as weve noted is something

    which takes objects to other objects. So we can think of a function such as x+3 as

    pairing each number with another. The list of pairs so determined is called the value

    range or extension of the function. So for x+3 wed have: (1,4); (2,5); (3,6) etc.

    Frege treats functions extensionally, which is to say that he identifies functions which

    have the same extension. This is because he believes that the semantic value of acompound expression is completely determined by the semantic values of its

    components. So, provided two expressions have the same extension, interchange of

    one with the other wont affect the semantic value of the whole.

    And now we can see how wed give an account of how the semantic-value of

    complex expression is determined. That is, if we had specifications of what the names

    in our language refer to and of the extensions of the functional expressions then wed

    be able to work out the truth-values of elementary sentences.

    Example of a Primitive Semantic Theory

    Axioms

    (i) The denotation of Freda is Freda

    (ii) The denotation of Mary is Mary

    (iii) The denotation of Lucy is Lucy

    (I) The extension of The mother of x is (Freda, Mary); (Mary, Lucy)

    (II) The extension of x is a lawyer is (Freda, False); (Mary, True); (Lucy, True)

    (C) A name formed from a name and a function denotes the second object in the

    ordered pair whose first member is the object denoted by the name, in the extension of

    the function.

    Examples:

    (a) The mother of Mary

    1. The mother of Mary denotes the second object in the ordered pair whose first

    member is the denotation of Mary, in the extension of The mother of x (C)

    2. The mother of Mary denotes the second object in the ordered pair whose first

    member is Mary, in the extension of The mother of x (ii)

    3. The mother of Mary denotes Lucy (I)

    We could use the same method to work out the denotation of, for example, The

    mother of the mother of Freda

    (b) The mother of Freda is a lawyer

    1. The mother of Freda is a lawyer denotes the second object in the ordered pair

    whose first member is the object denoted by The mother of Freda in the

    extension of x is a lawyer (C)

    2. The mother of Freda is a lawyer denotes the second object in the ordered pair

    whose first member is (the second object in the ordered pair whose first object

    is the denotation of Freda in the extension of The mother of Freda) in the

    extension of x is a lawyer (C)

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    3. The mother of Freda is a lawyer denotes the second object in the ordered pair

    whose first member is (the second object in the ordered pair whose first object

    is Freda in the extension of The mother of Freda) in the extension of x is a

    lawyer (i)

    4. The mother of Freda is a lawyer denotes the second object in the ordered pair

    whose first member is Mary, in the extension of x is a lawyer (I)5. The mother of Freda is a lawyer denotes the True. (II)

    The Referential View of the Meanings of Names

    Kilimanjaro means the highest mountain in Africa

    is grammatical, and, just possibly, an ordinary sentence of English. In this case the

    analysis would be something like the following:

    Kilimanjaro means the highest mountain in Africa iff Kilimanjaro refers tothe highest mountain in Africa.1

    What we shall learn in this section is that this analysis faces severe problems. These

    problems are sufficient to cast doubt on the original sentences as being an acceptable

    starting point. These lessons are due to Frege. We shall then go on to look at Russells

    alternative account which serves to show that the logico-syntactic category of singular

    terms is highly moot. Although we shall be looking at these questions from the point

    of view of giving an analysis of meaning, the discussion takes us to the heart of

    philosophical attempts to understand names and definite descriptions. This is scarcely

    surprising since the general point that we are pushing is that fixing on the starting

    point of analysis already requires considerable philosophical insight into how

    language works.

    Freges Argument for the Notion of Sense

    Freges argument2 focuses on identity statements. But this is primarily a heuristic

    device: he could have made the same point by focusing on elementary sentences in

    general. However its worth following through his reasoning about identity statements

    simply because, in doing so, we restrict our attention to the way names function.

    We often assert statements of identity. For instance: The morning star is the

    evening star; Everest is Gaurisanker; Clark Kent is Superman; Portia isBalthazar. The crucial thing to note is that these statements often carry useful

    information. If you remember the plot ofThe Merchant of Venice youll know that

    Bassanio would not have got himself in a pickle with Portia had he known that Portia

    and Balthazar are identical. Similarly Lois Lane would have acted quite differently

    had she known that Clark Kent is Superman: that piece of knowledge would have

    been informative to her. So statements of identity can be informative. No account of

    language and, in particular, of the functioning of names can be acceptable unless it

    makes sense of this fact.

    1 Note: we should not confuse these two claims. (i) The meaning of e is m iff e refers to m; and (ii) the

    meaning of e is given by the fact that e refers to m. (i) is the claim in the text; (ii) is a claim of quite adifferent sort that we shall only come to discuss in chapter six.2 See inter alia Frege (1980: 56-78)

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    Frege asks himself the question: what does the relation of identity hold

    between? It would seem that on the analysis of names with which we have so far been

    provided we can give only two answers. The relation either holds between the objects

    named by the names or it holds between the names themselves. Lets consider each

    suggestion in turn. Suppose that a and b are names and that a=b is true. If the

    relation holds between the objects denoted by the names then a=b cannot differ froma=a. For, since a=b is true, a and b name the same object. But clearly a=b

    and a=a differ because on many occasions (such as those above) statements of the

    form a=b are informative whereas those of the form a=a are uninformative since

    theyre known a priori to be true.

    Should we then take the identity statement to assert a relation between names?

    Frege says not since this can never be informative. Why so? Well what a sign means

    is a matter of speakers conferring meaning on the sign. So, if identity asserts a relation

    between names, then either a=b is false since a and b are different names or it

    registers a stipulation (which were entirely entitled to make) that the signs a and b

    are to be treated as the same name. On neither reading can a=b be treated as an

    informative statement.The point seems to be this. The character of a particular language is arbitrary

    in the sense that theres no intrinsic connection between the signs we use and what

    those signs refer to: whatever connections actually exist can be imagined to be quite

    other without supposing any difference in extralinguistic reality. But we cant simply

    suppose that the link of a name to its reference is purely arbitrary: that there is no

    saying how the use or the meaning of the name establishes the link. Why not?

    Because then there couldnt be informative identity statements, these would just be

    the laying down of arbitrary conventions. What we need to be able to see is that there

    is both an element of convention or arbitrariness and an element that is non-

    conventional or non-arbitrary in the relation of a name to its referent. That is, we

    need to see the link as mediated: the name is conventionally or arbitrarily related

    to something and that thing is non-conventionally, non-arbitrarily related to the

    referent. Frege calls this thing the sense of the name. How does this help with our

    problem?

    What we wanted to be able to explain is that we can learn something when we

    are told a=b. Well a is arbitrarily related to the sense of a and the sense of a is

    non-arbitrarily related to the referent of a. Likewise, b is arbitrarily related to the

    sense of b and the sense of b is non-arbitrarily related to the referent of b. What

    we learn when we are told that a=b is that the sense of a and the sense of b are

    related to the same object. And, since neither of these relations, is a matter of arbitrary

    this is a genuine piece of knowledge: conceivably, things might have been different.The point can be made in terms of what speakers understand when they grasp

    the meaning of an expression. If speakers grasped the reference of an expression then,

    for those regions of language which they understood, their understanding would

    suffice for them to arrive at a verdict on the truth-value of an identity statement. For,

    in such a case, theyd know the referent of each name as part of their understanding of

    it. They would simply need to reflect on this understanding in order to appreciate the

    truth or falsity of an identity statement. Clearly this misconstrues the nature of our

    understanding of language. So, we might say that in grasping the meaning of an

    expression speakers do not grasp as much as the reference of an expression.

    Conversely, it is clear that speakers do not grasp as little as the reference of an

    expression. For, if they did, then co-referring terms (terms which refer to the samething) would be synonymousindeed since Frege treats sentences as names for truth-

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    values all true sentences would be synonymous with one another, as would all false

    sentences. In this case we couldnt distinguish the sentences a=a and a=b in terms

    of meaning.

    The conclusion is that the reference of a term is not an ingredient of what

    speakers understand when they understand the terms meaning. In short, reference is

    not part of meaning. What do speakers grasp when they understand a term? Amongstother things they grasp its sense.

    Now if we are to explain the informativeness of a=b by saying that it informs

    us that the sense of a and the sense of b share a reference. Then it had better be the

    case that a and b have different senses. So it is possible for the same referent to

    have many senses.

    We are able now to explain or, better, to allow for the possibility of

    meaningful terms which dont have a reference. If we insist on thinking of the

    meaning of a term as what it refers to then terms which fail to refer will fail to have a

    meaning. But, once we introduce the notion of sense, it may be possible for a term to

    have a sense, and thus to be meaningful, yet fail to have a reference.

    Let us sum up so far what weve discovered about sense. (i) The sense of aterm is part of what speakers understand when they understand the terms meaning.

    (ii) The sense is non-conventionally, non-arbitrarily related to the terms reference.

    (iii) In fact the sense of the term is that ingredient of a terms meaning which

    determines its reference. For Frege, sense determines reference. (iv) The relation of

    sense to reference is many-one, that is, many senses may share the same reference. (v)

    In addition, a sense may fail to have a reference.

    We should note also that Frege thinks that these arguments can be extended to

    cover all terms of the language: all expressions have a sense. The sense of a sentence

    is a thought.

    So, according to Freges argument our analysis of the meaning of a name is

    wrong. The reasons for this relate to the information content conveyed by sentences

    which include names. And this is brought out by consideration of routine uses of such

    sentences. So the starting point of analysis (Kilimanjaro means the highest mountain

    in Africa) itself seems threatened; such sentences, even if they are sometimes used,

    cannot be thought to capture the essentials of the way names mean since they are

    blind to the names possession of a sense. Just to be clear, we are not saying that

    names have senses. Frege says this. But we want a starting point of analysis that

    doesnt beg the question against Frege, whether or not hes is right.

    Sense and Statements ofBelief

    Consider the following argument:

    Premise 1: King George doubts that Scott is the author ofWaverley.

    Premise 2: Scott is the author ofWaverley.Conclusion: Therefore King George doubts that Scott is Scott.

    Clearly something has gone very awry here. The first premise attributes an

    understandable doubt to King George who may simply be not very well informed

    about Scotts literary productions. The second premise states a truth. But the

    conclusion attributes to King George a doubt about the law of identity and clearly it is

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    unlikely that even he was so confused: such a conclusion is surely not warranted by

    the premises3.

    Now it is hard to explain what goes wrong here. What, in effect, premise 2

    tells us is that Scott and the author of Waverley have the same reference. And in

    that case we should be able to substitute one term for the other without changing the

    truth-value of any sentence in which they occur. This is a consequence of Fregescompositional view of semantic value. The semantic value of a name is its referent;

    that of a sentence is its truth-value. According to compositionality, the semantic value

    of a complex expression is determined by the semantic values of its components.

    What seems to be our problem is that applying this principle in the context of

    statements about someones beliefs, doubts, knowledge etc., leads from plausible

    truths to evident untruths and absurdities.

    How should we resolve the situation? We could either say that in the context

    of statements of belief etc. the principle of the compositionality of semantic values no

    longer holds. Or we could say that the semantic values of expressions in the context of

    statements of belief etc. change so that terms which shared a semantic value, that is,

    which referred to the same thing, may no longer do so. But what could the terms nowrefer to? Freges answer is that the terms shift their reference from what is their usual

    reference to what is usually their sense. So in the context of the sentence, King

    George doubts that Scott is the author of Waverley, the name Scott does not refer to

    Scott, it refers to the sense of Scott. Similarly the author of Waverley no longer

    refers to the author of Waverley (i.e., to Scott) it refers to the sense of the author of

    Waverley. Since the sense of Scott and the sense of the author of Waverley are

    different we can no longer be assured that when we substitute Scott for the author

    of Waverley the truth-value of the containing sentence remains unchanged. Note that,

    as a consequence of this account, senses are in the realm of reference.

    The Objectivity of Sense

    Different speakers can grasp the same sense. Indeed grasping the same sense is a

    condition for communication. When we communicate one speaker uses a sentence to

    express a certain thought; to do so she must grasp that thought. She successfully

    communicates only if her audience takes the sentence which she utters to express just

    that thought. In order to do so the audience must grasp that thought. Thus

    communication requires that speakers share the senses of their terms.

    The sense of an expression must thus be sharply distinguished from any set of

    subjective impressions associated with it. Ideas, impressions feelings are all things

    that are had by a certain subject: one can always ask whose idea, whose feeling etc.Something which can be had in this way cant be shared or, perhaps better, cant be

    known to be shared. The most that we can determine is qualitative differences

    between different peoples feelings, sensations or ideas. We cannot determine that

    they are qualitatively identical since for that, the sensations would have to be

    compared by a single subject. And thats clearly impossible since no subject can have

    anothers sensations or impressions. So sensations, feelings and ideas cannot be

    known to be shared. Thus, since communication requires that we share and can know

    that we share senses, senses must be sharply distinguished from ideas. That is, senses

    are not part of the subjective realm and, for Frege, this means that they are objective.

    (Another option might be to say that they belong to the inter-subjective realm but

    Frege doesnt consider this as a possible challenge to his dichotomy of subjective and3 See Russell (1956: 39-55).

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    objective.) Moreover for Frege to say that senses are objective is to reify them: senses

    are objective items in the world. He thus distinguishes three realms of existents. There

    is the realm of the actual, which includes ordinary middle-sized objects etc., then

    there is the subjective realm consisting of ideas and sense impressions and the like

    and finally there is a third realm consisting of senses and abstract objects such as

    numbers and the truth-values.

    Frege, G. Function and Concept in his Collected Papers and in his Philosophical

    Writings

    For exposition see the chapter by Grayling and Weiss in Philosophy: Further through

    the Subject (Anthony Grayling ed.) and also chapter 1 of Alexander Millers

    Philosophy of Language Freges Distinction between Sense and Reference4

    4 Terminological Note:

    There is an unfortunate lack of agreement amongst commentators about how to

    translate Freges German term bedeutung. It is variously translated as: denotation,

    nominatum, meaning and reference. Ill use reference and denotation pretty

    much interchangeably as translations. meaning wont be used in this way at all. And

    nominatum wont be used at all.