On 11/22/2013 12:14 PM, Rupert wrote:
<snip>
>>
>>>>> What's a meaning postulate?
>>
>>>>
http://www.glottopedia.org/index.php/Meaning_postulate
>>
>>> What's the directed graph of a meaning postulate?
>>
>> Meaning Postulates are formed through connections between elements of
>> meaning including AtomicUnitsOfMeaning such that all of these
>> connections form an acyclic directed graph.
>>
>
> How do you obtain the directed graph? Give an example of a meaning postulate.
>
"[...]
"To capture this restriction formally,
Montague turned to the device of so-called
meaning postulates. This device, first
used by Carnap in 1947 ["Meaning and Necessity -
A Study in Semantics and Modal Logic"], is
best thought of as a kind of constraint on
possible models. Carnap introduced it to
deal with analytically true sentences that
cannot be analyzed as being logically true
(true as a consequence of their syntactic
form), such as 'All bachelors are unmarried'.
If B is the predicate 'is a bachelor' and
M is 'is married', then Carnap's example of
a meaning postulate is
Ax( B(x) -> ~M(x) )
The intent of this postulate is that in considering
possible models for our language, we are to restrict
ourselves to models in which this formula is
true. This means, in effect, that in constructing
a possible model we may still choose the extensions
of non-logical constants of M and B in any way
we wish, except that every individual in the
extension of B must be excluded from the extension
of M in any 'admissible' model. Otherwise, no
constraints are placed on the extensions of these
predicates."
"Introduction to Montague Semantics"
Dowty, Wall, and Peters
"A method of semantical meaning analysis is developed
in this chapter. It is applied to those expressions
of a semantical system S which we call designators; they
include (declarative) sentences, individual expressions
(i.e., individual constants or individual descriptions)
and predicators (i.e., predicate constants or compound
predicate expressions, including abstract expressions).
We start with the semantical concepts of *truth* and
*L-truth* (logical truth) of sentences. It is seen from
the definition of L-truth that it holds for a sentence
if its truth follows from the semantical rules alone without
reference to (extra-linguistic) facts. Two sentences are
called (materially) equivalent if both are true or both
are not true. The use of this concept of equivalence
is then extended to designators other than sentences. Two
individual expressions are equivalent if they stand for
the same individual. Two predicators (of degree one) are
equivalent if they hold for the same individuals. *L-equivalence*
(logical equivalence) is defined for both sentences and
other designators in such a manner that it holds for two
designators if and only if their equivalence follows from
the semantical rules alone. The concepts of equivalence
and L-equivalence in their extended use are fundamental
to our method.
"If two designators are equivalent, we say also that they
have the same extension. If they are, moreover, L-equivalent,
we say that they have also the same intension. Then we look
around for entities which might be taken as extensions or
as intensions for the various kinds of designators. We find
that the following choices are in accord with the two identity
conditions just stated. We take as the extension of a predicator
the class of those individuals to which it applies and, as its
intension, the property which it expresses; this is in accord
with customary conceptions. As the extension of a sentence we
take its truth-value (truth or falsity); as its intension, the
property expressed by it. Finally, the extension of an individual
expression is the individual to which it refers; its intension
is a concept of a new kind expressed by it, which we call an
individual concept. These conceptions of extensions and intensions
are justified by their fruitfulness; further definitions and
theorems apply equally to extensions of all types or to intensions
of all types.
"A sentence is said to be extensional with respect to a
designator occurring in it if the extension of the sentence
is a function of the extension of the designator, that is
to say, if the replacement of the designator by an equivalent
one transforms the whole sentence into an equivalent one. A
sentence is said to be intensional with respect to a designator
occurring in it if it is not extensional and if its intension
is a function of the intension of the designator, that is to
say, if the replacement of this designator by an L-equivalent
one transforms the whole sentence into an L-equivalent one. A
modal sentence (for example, 'it is necessary that...') is
intensional with respect to its subsentence. A psychological
sentence like 'John believes that it is raining now' is neither
extensional nor intensional with respect to its subsentence."
"Meaning and Necessity - A Study in Semantics and Modal Logic"
Rudolf Carnap
You will laugh when you figure out what a "meaning
postulate" is. Continuuing, ...
"A complete construction of the semantical system S_1,
which cannot be given here, would consist in laying down
the following kinds of rules:
1.
rules of formation, determining the admitted
forms of sentences;
2.
rules of designation for the descriptive constants;
3.
rules of truth, which we will explain now;
4.
rules of ranges, to be explained in the next section.
Of the rules of truth, we shall give here
only three examples [...]
"[...] The rules of truth together constitute a
recursive definition for 'true in S_1", because
they determine, in common with the rules of designation,
for every sentence in S_1 a sufficient and necessary
condition of its truth. Thereby, they give an interpretation
for every sentence."
"Meaning and Necessity - A Study in Semantics and Modal Logic"
Rudolf Carnap
What is important, for the moment are the "rules
of designation". Here is what Carnap wrote to
explain them:
"S_1 contains descriptive constants (that is, non-logical
constants) of individual and predicate types. The number
of predicates in S_1 is supposed to be finite, that of
individual constants may be infinite. For some of these
constants, which we shall use in examples, we state here
their meanings by semantical rules which translate them
into English.
"1-1. Rules of designation for individual constants
's' is a symbolic translation of 'Walter Scott'
'w' is a symbolic translation of '(the book) Waverley'
"1-2. Rules of designation for predicates
'Hx' is a symbolic translation of 'x is human (a human being)'
'RAx' is a symbolic translation of 'x is a rational animal'
'Fx' is a symbolic translation of 'x is (naturally) featherless'
'Bx' is a symbolic translation of 'x is a biped'
'Axy' is a symbolic translation of 'x is an author of y'
"The English words here used are supposed to be understood
in such a way that 'human being' and 'rational animal' mean
the same."
"Meaning and Necessity - A Study in Semantics and Modal Logic"
Rudolf Carnap
It is important to understand exactly why the statement
following the rules of designation is being made. Recall
from above,
"Carnap introduced it to deal with analytically
true sentences that cannot be analyzed as being
logically true (true as a consequence of their
syntactic form), such as 'All bachelors are
unmarried'."
"Introduction to Montague Semantics"
Dowty, Wall, and Peters
There are a number of participants in these newsgroups
who do not grasp that the analytical truth of "All bachelors
are unmarried" is not a notion of logical truth. Carnap
introduces these rules of designation specifically to
handle analytical truth separately, as intensions.
Carnap, however, does not distinguish analytical truth
and logical truth in the sense of the authors above.
Rather, Carnap distinguishes between *truth* and *L-truth*.
Since the latter is an abbreviation for "logical truth"
Carnap is using the phrase "logical truth" in the sense
which Frege attributed to intensional logicians. Recently
I had been branded a Nazi for trying to keep these notions
distinctly separated.
Carnap's statements for defining L-truth proceed through
notions from Leibniz and Wittgenstein:
"We shall introduce L-concepts with the help of the
concepts of state-description and range. Some ideas
of Wittgenstein were the starting point for the
development of this method.
"A class of sentences in S_1 which contains for every
atomic sentence either this sentence or its negation,
but not both, and no other sentences, is called a
*state-description* in S_1, because it obviously gives
a complete description of a possible state of the
universe of individuals with respect to all properties
and relations expressed by predicates of the system.
Thus the state-descriptions represent Leibniz' possible
worlds or Wittgenstein's possible states of affairs.
"It is easily possible to lay down semantical rules which
determine for every sentence in S_1 whether or not it
holds in a given state description. That a sentence
holds in a state-description means, in nontechnical
terms, that it would be true if the state-description
(that is, all sentences belonging to it) were true.
[...]
"The class of all those state-descriptions in which a
given sentence s_1 holds is called the range of s_1.
All the rules together, of which we have just given
five examples [standard model-theoretic statements, fom],
determine the range of any sentence in S_1; therefore,
they are called rules of ranges. By determining the
ranges, they give, together with the rules of designation
for the predicates and the individual constants, an
interpretation for all sentences in S_1, since to know
the meaning of a sentence is to know in which of the
possible cases it would be true and in which not, as
Wittgenstein has pointed out.
"The connection between these concepts and that of
truth is as follows: There is one and only one
state-description which describes the actual state
of the universe; it is that which contains all true
atomic sentences and the negations of those which
are false. Hence, it contains only true sentences;
therefore, we call it the true state-description. A
sentence of any form is true if and only if it holds
in the true state-description. These are only
incidental remarks for explanatory purposes; the
definition of L-truth will not make use of the
concept of truth"
"[...]
"2-1. Convention. A sentence s_1 is L-true in a
semantical system S if and only if s_1 is true in
S in such a way that its truth can be established
on the basis of the semantical rules of the system
S alone, without any reference to (extra-linguistic)
facts.
"This is not yet a definition of L-truth. It is an
informal formulation of a condition which any proposed
definition of L-truth must fulfill in order to be
adequate as an explication of our explicandum. Thus,
this convention has merely an explanatory and heuristic
function.
"How shall we define L-truth so as to fulfill the
requirement 2-1? A way is suggested by Leibniz'
conception that a necessary truth must hold in all
possible worlds. Since our state descriptions
represent the possible worlds, this means that a
sentence is logically true if it holds in all
state-descriptions. This leads to the following
definition:
"2-2. Definition. A sentence s_1 is *L-true* (in
S_1) <=df=> holds in every state-description (in S_1)."
"Meaning and Necessity - A Study in Semantics and Modal Logic"
Rudolf Carnap
Well, I have transcribed a lot here so that
the development of the notion can be appreciated.
It has to do with expressions whose analysis
led to Bolzano's conclusion that one could not
define simple substance (individuals) using term
logic. This is one of the paths by which the
foundations of mathematics came to endorse the
notion of "undefined language primitives" in its
dogma.
To give you a slightly more up to date sense of
what is really involved, here is an excerpt from
"Foundations of Intensional Semantics" by Fox and
Lappin,
"Now, consider the following theorem from
Johnstone ("Stone Spaces", 1982, p. 14) and
its corollary:
"Theorem 2(Johnstone): For any a, b in a distributive
lattice L such that ~( a <= b ), there is a homomorphism
h: L -> 2 in which h(a)=1 and h(b)=0.
"Corollary 1: For any a, b in a distributive lattice
L, if every homomorphism h: L -> 2 is such that
h(a)=h(b), then a=b
"Proof: [...]
"Corollary 1 specifies a direct connection between
provability and the identity relation between propositions
in a lattice. It has the consequence that if the
entailment relation among propositions can be modeled
as a partial order in a distributive lattice, identity
of propositions reduces to logical equivalence (mutual
entailment). If we formulate a semantic theory in
algebraic terms, we can use Corollary 1 as an important
measure of its success in avoiding this reduction.
"This result implies that there are only two basic
strategies that can be used to sustain a distinction
between logical equivalence and intensional identity.
On the first, impossible worlds are added to the model
theory to permit propositions that are equivalent across
the set of possible worlds to receive different truth-values.
These impossible worlds violate either the meaning
postulates governing the interpretations of non-logical
constants in the language or the interpretations of
logical constants fixed for the set of possible worlds.
"The second strategy involves weakening the partial
order relation that models entailment to a non-antisymmetric
preorder in which mutual entailment does not force
identity. This turns the algebraic structure of the
semantic theory into a bounded distributive prelattice
in which equivalent propositions are distinguished."
Hope this helps.
Mr. Olcott appears to be another fine person that
has failed to do his homework.