Is knowing under what conditions a statement is true either necessary or sufficient for knowing what the statement means? 


To say that knowing under what conditions a statement is true (T) is necessary and sufficient for knowing what the statement means (M) is to say that "T if and only if M".  Which is to say that M and T are equivalent, that meaning can be understood in terms of truth-conditions.  (Or vice versa, obviously.  But presumably the "truth-conditions" are better understood than "meaning," and "meaning" is the term needing explication.)  This theory of meaning is known as truth-conditional semantics.  What the essay title is asking, then, is whether this theory holds, and that whether the meaning of a statement can be understood in terms of its truth-conditions. 

In this essay, I will answer that question with "No!"  To support this conclusion, I will first provide a prĂ©cis of the history and nature of truth-conditional semantics, and then outline a short selection of what I consider fatal difficulties facing the theory.  I will argue that it is neither necessary nor sufficient to know a statements truth conditions in order to know what the statement means.  (Although this is not do deny that once one knows the meaning of a statement, knowledge of the truth-conditions follows.)  In outlining the difficulties facing truth-conditional semantics, I will show that it is not necessary to know the truth conditions to know the meaning of a statement, and that it is not sufficient to know the truth-conditions to know the meaning of a statement.

The truth-conditional theory of meaning is principally associated with Donald Davidson who first explicated the "modern" version almost 50 years ago in his article "Truth and Meaning" (1).  Davidson attempted to carry out for the semantics of natural language what Tarski's theory of truth(2) for artificial languages tried to do for logic.  Tarski attempted to define truth for artificial languages like logic and mathematics in terms of a presupposed notion of meaning.  Davidson inverted Tarski's argument and attempted to define meaning for natural languages in terms of a presupposed notion of truth.  In taking this approach, Davidson harks back to Frege and Wittgenstein.  Though the concept of truth is central in Frege's work, he leaves it undefined.  From Logical Investigations: "It seems likely that the content of the word 'true' is sui generis and undefinable"(3)  And from Wittgenstein: "to understand a proposition means to know what is the case if it is true"(4).  A more recent advocate of truth-conditional semantics is Jerry Fodor.  In The Language of Thought, Fodor documents his premise that "one understands a predicate only if one knows the conditions under which sentences containing it would be true"(5).

To understand the motivation behind the truth-conditional theory of meaning, and the intuition that has been driving its development over the years, I draw the distinction between top-down and bottom up theories of meaning.  Bottom-up theories of linguistic meaning begin by explicating the meaning of small parts of a language (words, "stock phrases," and idioms).  Other meanings are then composed of those parts.  Meanings of sentences are viewed as resulting from the meaning of its parts (words), and a rule of composition.  Top-down theories, on the other hand, begin by explicating the meaning of large utterances (usually sentences).  The meaning of the parts of language (words, etc.) is determined in terms of how they play a role in these larger entities.  Truth-conditional semantics is a top-down theory of meaning.  Davidson followed Frege in maintaining that the sentence, rather than the word, is the central repository of meaning.  He also followed Quine in viewing meaning in a holistic manner -- the meaning of any sentence determined collectively by the meaning of all the sentences in the language.

"If sentences depend for their meaning on their structure, and we understand the meaning of each item in the structure only as an abstraction from the totality of sentences in which it features, then we can give the meaning of any sentence (or word) only by giving the meaning of every sentence (and word) in the language. Frege said that only in the context of a sentence does a word have meaning ; in the same vein he might have added that only in the context of the language does a sentence (and therefore a word) have meaning."(6)

Another dimension of distinction is that between mentalistic (internalist) and behavioristic (externalist) theories of meaning.  A bottom-up mentalistic theory of meaning would explain meaning in terms of the hypothesis that words are labels for such mentally internal phenomena as thoughts, ideas, or concepts.  A top-down mentalistic theory would explain meaning in terms of the hypothesis that sentences name an abstract internal mental construct -- usually called propositions.  Davidson objects to the mentalistic approach because he argues that they merely push the problem of explaining linguistic meaning back into the problem of explaining the meaning of thoughts or propositions.  Instead, Davidson finds an externalist alternative.  He again follows Quine, and founds his truth-theoretic semantics on the then popular orthodoxies of behaviorism and verificationism.  Verificationism, applied to linguistic meaning, holds that sentences have a meaning either because they are pure logic or they are determined by the kinds of empirically observable effects they could possibly have if true.  Behaviorism, applied to linguistic meaning, holds that those empirically observable effects include the verbal behaviors of speakers of the language.  Sentences that we could never confirm as true or false are meaningless.  (A gross over-simplification, of course, but it will suffice for this essay.) 

Truth-conditional linguistic theories, Davidson's as well as those built upon Davidson, are founded on the idea that the linguistic meaning of a sentence is constituted by the empirically observable external phenomena of its truth conditions.  Thus, to know what a sentence means is to know what it is for that sentence to be true.  So, to use the standard example, because "snow is white" is true if and only if snow is white, the meaning of "snow is white" is snow is white.  For a truth-conditional theory of meaning to know the conditions under what a statement would be true is to know what the statement means.

However a number of criticisms of truth-conditional semantics have surfaced in the literature to undermine the plausibility of this approach to meaning.  Not the least of these are the problems Davidson identified in his original article.  Even after 50 years of work by various advocates, truth-conditional semantics still has no generally recognized solutions to such problems as:

(i) the truth-conditions constituting the meaning of counter factual conditionals, subjunctive sentence constructions, probabilities, and causal relations;

(ii) the role in sentence meaning of adverbs and attributive adjectives;

(iii) how meaning is established for embedded sentences in belief ascriptions;

(iv) how to treat utterances without obvious truth values,  such as performatives ("I promise!"), imperatives ("Don't do that!"), interrogatives, and non-sentential expressives ("Yuk!").

The initial appeal of truth-conditional semantics is the intuitive appeal of the notion that if one understands a statement, one also understands the conditions under which the statement would be true.  But there has been a lot of debate in the literature.  For example, when it comes to counterfactual conditionals, Lewis(7) offers a truth-conditional approach, but Mackie(8) offers an alternative account in terms of causal laws.  But the critical question reverses the sense of the intuition - whether one must know what the statement means before one can know the conditions under which the statement would be true. 

One serious criticism comes from Scott Soames(9).  He argues that in its traditional form, a truth-conditional concept of meaning gives every necessary truth precisely the same meaning.  All necessary truths are, by definition, true under all conditions.  This means that every necessarily true statement is true in precisely the same conditions.  Furthermore, the truth conditions of any random statement are logically equivalent to the conjunction of the conditions that make that statement true and any necessary truth.  This means that by truth-conditional semantics, any random statement means the same as its meaning plus a necessary truth.  To use the standard example again: if "snow is white" is true iff snow is white, then it is logically necessary that "snow is white" is true iff snow is white and 2+2=4.  Therefore "snow is white" means both that snow is white and that 2+2=4.  And this process of conjoining necessary truths can proceed indefinitely.  That seems intuitively wrong.  In singling out just which of the potentially infinite number of conjoined truth-conditions should make up the statement's meaning, the only available guide is the statements meaning.  Davidson's response to this problem is his holism about meaning.  Individual sentences acquire meaning only within the coherent network that is the language.  His rejoinder to Soames is that the necessary coherence will weed-out any irrelevant concatenations.  But even on this basis, understanding the meaning of any individual sentence precedes the understanding of which are the relevant truth-conditions for that sentence.  In other words, knowing the statements truth-conditions cannot be sufficient for knowing the meaning of the statement.

Closely allied with the criticism from necessary truth, is the criticism from equivalent extensions.  Consider the two statements "a zebra has a heart" and "a zebra has a kidney" -- a classic philosophical example.  In this actual world, it turns out that "creature with a heart" has the same extension as "creature with a kidney".  Everything which is in fact a creature with a heart is also a creature with a kidney, and vice versa.  But if evolution had gone differently, or in different possible worlds, there might have been a species of creature which had hearts but no kidneys, or vice versa.  Because these two example sentences have isomorphic extensions, they have equivalent truth conditions.  They are both true or false in exactly the same circumstances, at least in this world.  But it is intuitively obvious that they do not mean the same thing.  In other words, again, knowing the statements truth-conditions cannot be sufficient for knowing the meaning of the statement.

A similar source of criticism comes because statements can be meaningful even if they talk about non-existent states of affairs.  "Santa Claus is jolly" is meaningful, even though Santa Claus does not exist.  What truth-conditions would establish the meaning of such sentences?  This seems to require a theory of truth that admits of non-existent states of affairs.  As such, it raises objections from those philosophers who are concerned about the ontological commitments that seem to be required.  Intuitively, it appears that understanding the meaning of "Santa Claus is jolly" is not the same sort of thing as knowing under what conditions a non-existent and perhaps poorly defined entity could be jolly.

Truth-conditional theories also have similar technical difficulties in dealing with indexical elements and some relational terms of language.  Davidson's own response to this is to treat indexical statements as relativized statements -- statements considered as utterances by a speaker at a time.  Putting the meaning of "now" or "I" (or any of the other indexicals) into something that truth-conditions could apply to would seem to demand that they be "translated" out of the initial statement.  And the same problem would seem to infect such relational terms as "tall" or "fat".  Without specifying a specific context in which they have some determinate meaning ("taller than Bob" or "fatter than the average American teenager in 2012"), it is difficult to see how to relativize it without presupposing the meaning being "translated".  In other words, translating an indexical statement or a statement with vague relational terms into a properly relativized statement presupposes an understanding of the meaning of the statement.  In other words, knowing the statements truth-conditions cannot be necessary for knowing the meaning of the statement.

Truth-conditional semantics provides a theory of the meaning of a sentence in an object language, in terms of an explanation in terms of a meta-language.  It may be a good thing to know that "der schnee ist weiss" is true if and only if snow is white.  And it may provide a good explanation of what "der schnee ist weiss" means in English.  But it does not provide any explanation of what the right side of that equivalence means.  What the truth-conditional theories of meaning do not provide is an explanation of what it means to say that snow is white (the meta language statement, not the quoted sentence).  There is a distinction that must be drawn between the question "What is the meaning (translation) of this sentence?" and "In virtue of what does the sentence have that meaning?"  One can argue that truth-conditional semantics provides the meaning (translation) of the symbol in quotes ("der schnee ist weiss") by using words in some meta-language (snow is white).  What is missing is a foundational theory of meaning -- a theory that explains what it is about the world (or about some person or group) that gives the quoted sentence ("der schnee ist weiss") the meaning that it has.  So, again, knowing the truth-conditions spelled out in a meta-language for a statement in the object language is not sufficient for knowing the meaning of that object-language statement unless one already knows the meaning of those meta-language statements, and it is not necessary knowing the meaning of that object-language statement if one does not already know the meaning of those meta-language statements.

So the answer to the essay's title question is "No!", knowing a statements truth-conditions is neither necessary nor sufficient for knowing what the statement means.  Meaning is not equivalent to the statement's truth-conditions.  But obviously, once one knows what a statement means, one can come to know (after more or less contemplation) the truth-conditions that would render the statement true -- in some possible world.  And if one is skilled in logic, then knowing the meaning of the statement presumably lets one know what logically follows from that statement.  (Although since not many people are skilled in logic, that is perhaps not a good foundation on which to build a theory of meaning.)


Notes & References

(1)  Davidson, Donald;  "Truth and Meaning" in Synthese, Vol 17, No 3 (Sep, 1967), pp 304-323.

(2)  Tarski, Alfred;  "The concept of truth in the languages of the deductive sciences" (published in Polish), 1933.  Expanded English translation in Tarski's Logic, Semantics, Metamathematics, Papers from 1923 to 1938, pp. 152--278.

(3)  Frege, Gottlob;  Logical Investigations (Library of philosophy and logic), Blackwell Publishers, Oxford, England, 1977. ISBN 978-0-631-17190-4.  Pg 4.

(4)  Wittgenstein, Ludwig;  Tractatus Logico-Philosophicus, downloaded from URL=<>. Para 4.024.

(5)  Fodor, Jerry;  Language of Thought, Harvard University Press, Cambridge, Massachusetts, 1980, ISBN 978-0-674-51030-2.

(6)  Davidson, Donald;  "Truth and Meaning", op cit. Pg 308.

(7) Lewis, David K.; Counterfactuals, 2nd Edition, Wiley-Blackwell, New York, New York, 2001. ISBN 978-0-631-22425-9.

(8) Mackie, John L.; The Cement of the Universe, Oxford University Press, New York, New York, 1980. ISBN 978-0-198-24642-8.

(9)  Soames, Scott;  "Truth, Meaning and Understanding" in Philosophical Studies: An International Journal for Philosophy in the Analytic Tradition, Vol. 65, No. 1/2, (Feb 1992), pp:17-35., URL=<>.


Brennan, Andrew;  "Necessary and Sufficient Conditions"  The Stanford Encyclopedia of Philosophy (Winter 2012 Edition), Edward N. Zalta (ed.), URL=<>.

Davidson, Donald;  "Radical Interpretation Interpreted" in Philosophical Perspectives, Vol 8. (1994), pp. 121-128. URL=<>.

Davidson, Donald;  "Responses to Barry Stroud, John McDowell, and Tyler Burge" in Philosophy and Phenomenological Research, Vol 67, No 3 (Nov 2003), pp. 691-699. URL=<>.

Davidson, Donald;  Truth, Language, and History, Oxford University Press, New York, New York, 2005. ISBN 978-0-198-23757-0.  Kindle Edition.

Davidson, Donald & Lapore, Earnest & Ludwig, Kirk;  The Essential Davidson, Oxford University Press, New York, New York, 2006. ISBN 978-0-199-28886-1.  Kindle Edition.

Dummett, Michael .A.E.; "What is a Theory of Meaning" in Mind and Language, S. Guttenplan (ed.), Oxford University Press, Oxford, England. 1977, ISBN 978-0-198-75043-7.

Dummett, Michael;  The Seas of Language, Clarendon Press, Oxford, England. 1993. ISBN 0-198-23621-2.  Kindle Edition.

Edwards, Jim;  "Theories of Meaning and Logical Constants: Davidson versus Evans" in Mind, New Series, Vol 111, No 442 (Apr 2002) pp. 249-279. URL=<>.

Evans, Gareth & McDowell, John (eds.); Truth and Meaning: Essays in Semantics, Oxford University Press, Oxford, England, 1999. ISBN 978-0-198-25007-4.

Glanzberg, Michael;  "Semantics and Truth Relative to a World" in Synthese, Vol 166, No 2 (Jan 2009), pp. 281-307. URL=<>.

Grice, H. Paul;  Studies in the Way of Words, Harvard University Press, Cambridge, Massachusetts, 1991. ISBN 978-0-674-85271-6.

Grice, H. Paul; "Meaning" in The Philosophical Review, Vol 66 (1957), pp 377-388. (Reprinted in his Studies in the Way of Words.)

Grice, H. Paul;  "Utterer's Meaning, Sentence Meaning, and Word Meaning" in Foundations of Language, Vol 4 (1968), pp 225-242. (Reprinted in his Studies in the Way of Words.)

Horwich, Paul;  "What's Truth Got to Do With It?" in Linguistics and Philosophy, Vol 31, No 3 (2008), pp. 309-322. URL=<>.

Loar, Brian;  "Two theories of Meaning" in Truth and Meaning: Essays in Semantics, Evans, Gareth & McDowell, John (eds.), Oxford University Press, Oxford, England, 1999. ISBN 978-0-198-25007-4. pp 138-161.

Lycan, William G.;  Philosphy of Language: A Contemporary Introduction, 2nd Edition. Routledge, New York, New York, 2008. ISBN 978-0-203-93000-7.

Malpas, Jeff;  "Donald Davidson" in The Stanford Encyclopedia of Philosophy (Winter 2012 Edition), Edward N. Zalta (ed.), URL=<>.

Soames, Scott; "Truth and Meaning -- In Perspective" in Midwest Studies in Philosophy, Vol 32 (2008).

Speaks, Jeff, "Theories of Meaning" in The Stanford Encyclopedia of Philosophy, Edward N. Zalta (ed.), URL=<>.

Tarski, Alfred;  Logic, Semantics, Metamathematics, Papers from 1923 to 1938, John Corcoran (ed.), Hackett Publishing Company, Indianapolis, Indianna, 1983. ISBN 978-0-915-14476-1.

Wikipedia contributors;  "Truth-conditional Semantics" in Wikipedia, The Free Encyclopedia. URL=<>.


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