Obviously one of the most important general and fundamental questions is: What is truth? This is a difficult question—if only because we tend to assume a certain conception of the truth as we look for the truth about the truth! Nonetheless, there are a set of interesting philosophical responses to it. Certainly the most popular and influential thus far has been the correspondence theory of truth. This theory can be traced back to Aristotle’s (384-322 B.C.) influential definition of truth (see his Metaphysics 1011b25):
- “To say of what is that it is not, or of what is not that it is, is false, while to say of what is that it is, and of what is not that it is not, is true.”
According to this account, I speak a falsehood if (1) I say that some fact, “what is”, is not the case (“George Washington was not the first President of the United States”) or (2) I say that something which “is not” is a fact (“George Washington was the third President of the United States”).
I speak the truth if (1) I say that some fact, “what is”, is the case (“George Washington was the first President of the United States”) or (2) I say that something which isn’t a fact is not the case (“Hillary Clinton is not the 45th president of the United States”).
Here is a more modern formulation:
- A proposition x is true if and only if x corresponds to some fact;
- A proposition x is false if and only if x does not correspond to any fact.
So if I claim “Hillary Clinton became the 45th president of the United States” then what I claim is false since it doesn’t correspond to a fact. If I claim “Donald Trump is the 45th President of the United States” then what I claim is true because it does correspond to a fact.
Typically those who embrace this theory of truth accept that truth and falsity are properties of propositions that assert or deny something about facts. Truth and falsity are not properly predicated of facts: we don’t say a television set in front of us is true or false. Rather, we say it is a fact about the world and that there are a variety of propositions that assert things about the television set that can be true or false.
Now, why would we believe in this theory? In the online Stanford Encyclopedia of Philosophy’s (SEP) entry “The Correspondence Theory of Truth” (for the entry go here) we get one simple answer:
“The main positive argument given by advocates of the correspondence theory of truth is its obviousness. Descartes: “I have never had any doubts about truth, because it seems a notion so transcendentally clear that nobody can be ignorant of it…the word ‘truth’, in the strict sense, denotes the conformity of thought with its object” (1639, AT II 597). Even philosophers whose overall views may well lead one to expect otherwise tend to agree. Kant: “The nominal definition of truth, that it is the agreement of [a cognition] with its object, is assumed as granted” (1787, B82). William James: “Truth, as any dictionary will tell you, is a property of certain of our ideas. It means their ‘agreement’, as falsity means their disagreement, with ‘reality’” (1907, p. 96). Indeed, The Oxford English Dictionary tells us: “Truth, n. Conformity with fact; agreement with reality”.” (see section 4)
So self-evidence can be appealed to as a justification. Another reason is this: if we don’t separate what we assert from the facts, then it seems the facts themselves will be what are true or false. But how can facts be false? According to the correspondence theory, when we utter a falsehood we state something that doesn’t correspond to the facts and this statement can be false. By separating propositions and facts in this way we can account for falsehood. But if all we have are facts then there would be no way to account for that which is not a fact.
Despite this obviousness, plenty of objections have been brought against the theory. For example, it has been argued that there may be truths in a certain domain, moral or logical truths for example, that have no corresponding facts. Others have pointed out that the nature of facts is unclear and, to make sense of them, we have to employ the very concept of truth the facts were introduced to explain. Consider this passage from the Internet Encyclopedia of Philosophy entry “Truth”:
“In addition to the specific fact that ball 1 is on the pool table and the specific fact that ball 2 is on the pool table, and so forth, is there the specific fact that there are fewer than 1,006,455 balls on the table? Is there the general fact that many balls are on the table? Does the existence of general facts require there to be the Forms of Plato or Aristotle? What about the negative proposition that there are no pink elephants on the table? Does it correspond to the same situation in the world that makes there be no green elephants on the table? The same pool table must involve a great many different facts. These questions illustrate the difficulty in counting facts and distinguishing them. The difficulty is well recognized by advocates of the Correspondence Theory, but critics complain that characterizations of facts too often circle back ultimately to saying facts are whatever true propositions must correspond to in order to be true. Davidson has criticized the notion of fact, arguing that “if true statements correspond to anything, they all correspond to the same thing” (in “True to the Facts”, Davidson ).”
Others have argued that correspondence theories are actually too obvious: “They are trivial, vacuous, trading in mere platitudes. Locutions from the “corresponds to the facts”-family are used regularly in everyday language as idiomatic substitutes for “true”. Such common turns of phrase should not be taken to indicate commitment to a correspondence theory in any serious sense.” (SEP). Many have claimed that the whole notion of a correspondence between a proposition and a fact is mysterious: how can the correspondence take place? If the relation is one of resemblance, how can we make sense of such resemblance? Can the relation be physical? If not, what would the relationship be? And some have even argued that the correspondence theory “must inevitably lead into skepticism about the external world, because the required correspondence between our thoughts and reality is not ascertainable” (SEP).
To be sure, there have been plenty of responses to these objections. But they have led some philosophers to embrace other theories of truth such as the pragmatic theory of truth, which maintains that a proposition is true if it is useful to believe, or the coherence theory of truth which maintains that the truth of any proposition consists in its coherence with some set of other propositions (see The Stanford Encyclopedia of Philosophy’s entries on these theories and others for details, objections, etc.). And there are plenty of other options as well, including the identity theory of truth, which states that true propositions are facts, and the deflationary theory of truth, which maintains that to assert a statement is true is just to assert the statement itself. “For example, to say that ‘snow is white’ is true, or that it is true that snow is white, is equivalent to saying simply that snow is white, and this, according to the deflationary theory, is all that can be said significantly about the truth of ‘snow is white’” (SEP).
Nonetheless, the correspondence theory enjoys a weak majority among philosophers (SEP) and continues to be refined into more plausible versions. For an impressive recent effort see Joshua Rasmussen’s Defending the Correspondence Theory of Truth (Cambridge).