What is truth? Weíll look at a number of answers to this question that philosophers have given.
The first is called the correspondence theory, and we can define it as follows:
It is true that P ("P" stands for a proposition) iff P corresponds with the facts.
So "truth" means "correspondence with the facts." Thatís a traditional formulation of the theory. So let me try to explain what it says. For example, itís true that some dogs bark if the proposition, "Some dogs bark," corresponds with the facts. Which facts? Actually, just one: the fact that some dogs bark. So suppose that it is a fact that some dogs bark (thatís not hard to suppose). Then we can improve our example. We could say: itís true that some dogs bark if, and only if, the proposition, "Some dogs bark," corresponds with the fact that some dogs bark. Or we could say: itís true that God exists if, and only if, the proposition, "God exists," corresponds with the fact that God exists.
The most commonly cited problem for the correspondence theory is this question: what is correspondence? When does a proposition correspond with the facts? Well, you can think of correspondence as a sort of matching-up relation -- if a proposition can be matched up with a fact, then it corresponds to that fact. But thatís still puzzling, isnít it? I mean, when does a proposition "match up" with a fact? To say that "correspondence" means "matching up" doesnít really shed a whole lot of light on the subject.
Well, one thing we might observe in any case is that, in order for a proposition to be true, according to the correspondence theory, there must be some fact to which it corresponds. So a fact has to exist in order to be matched up a proposition. And remember, weíve already decided which fact that a proposition has to correspond with: the proposition that P has to correspond with the fact that P, if the proposition that P is true.
So here is a suggestion that can help get us around the objection about correspondence. We can say that it is true that P if, and only if, there exists a fact that P. If we put it like that, then we donít have to talk about correspondence at all. We just say: itís true that some dogs bark if, and only if, there exists a fact, that some dogs bark. And we could put it even simpler than that:
It is true that P iff it is a fact that P.
So consider that the revised version of the correspondence theory: P is true when it is a fact that P. Itís true that dogs bark if itís a fact that some dogs bark. Itís true that God exists if itís a fact that God exists. Itís true that snow is white if itís a fact that snow is white. And so on. We can regard that as explaining what it means for a proposition to correspond with a fact: basically, if there is a fact that P, then that fact corresponds with the proposition that P.
But this reformulation of the theory faces now a different problem. Namely what are facts, and what does it mean to say that facts exist, or that there is some alleged fact? Look at the problem like this. Our reformulation basically says that "true proposition" means "factual proposition." So then we have to ask ourselves: "Have we really explained anything about truth, about true propositions, if we merely said that they are factual? Because then arenít we just letting this other word, Ďfactí, do all the work of the word weíre confused about, Ďtrueí? And then wouldnít we have to give some account of what facts are?"
There are at least two different ways to reply to this objection. The first way to reply is to actually offer a theory of what facts are. This is something that philosophers, this century, have actually tried to do. They say things like this: some facts are basically combinations of objects together with their properties or relations; so the fact that Fido barks is the combination of an object, Fido, with one of Fidoís properties, that he barks. But of course that is only one kind of fact; there would be other kinds of facts, about all dogs; or about the relation between dogs and cats; and so on. But the idea is that it is possible, anyway, to specify and categorize all those different kinds of facts. And then youíve got an answer to the question, "What are facts?" You say: itís one of these sorts of things (pointing to your theory of facts). And when it is asked, "What does it mean for a fact to exist?" you can answer: well, itís for each part of a fact to exist. So if Fido exists, and Fidoís barking exists, then the fact that Fido bark exists. And thatís what makes it true to say that Fido barks.
I personally think thatís a very appealing way to answer the objection. But there is another way, which has been perhaps even more popular. And this is to offer an even further stripped-down theory. First, observe that if I say that itís a fact that P, I might as well have just said, "P." If I say, for example, that itís a fact that some dogs bark, then why donít I just say, "Some dogs bark"? Why do I have to declare that itís a fact? If Iím saying it, then Iím implying that itís a fact, am I not? Sure. Well notice that, in the previous theory of truth, these words occur: "it is a fact that P." So then why donít we just say "P" in place of "it is a fact that P"? I mean, suppose Iím right, and when I say "Itís a fact that P," I really mean nothing more than when I say "P." Then why not just substitute "P" in for "it is a fact that P" in our previous, revised correspondence theory? Then we donít talk about facts at all. So hereís the new, even further stripped-down theory:
It is true that P iff P.
Thatís it. And some people say that thatís basically all there is to say about truth. This bare-bones theory is called "the redundancy theory of truth," and it is due to F. P. Ramsey, an English philosopher who lived about the same time as Moore and Russell. Itís called "the redundancy theory" because it basically implies that saying that something is true is always redundant. This is very similar to the "performative theory of truth" mentioned in our reading on p. 116. The idea is that, instead of saying, "It is true that some dogs bark," you could, without loss of meaning, say simply, "Some dogs bark." In principle we could always eliminate talk of truth, in favor of simply forthrightly asserting whatever it is that we say is true.
Now thereís one simple objection to the theory that might occur to you. You might say: "Well, if I claim, ĎPigs fly,í then the redundancy theory says that itís true that pigs fly! If I claim that philosophy is simple, then itís true that philosophy is simple!" This is a bad objection. Itís bad because it has the redundancy theory wrong. The redundancy theory doesnít say: "Itís true that P iff I claim that P." It says: "Itís true that P iff P." So, if pigs fly, if pigs do indeed fly, then itís true that pigs fly. Nothing wrong with saying that: thatís correct. If pigs did fly, then it would be true that pigs fly. But thatís quite different from saying that, if I claim that pigs fly, then itís true that pigs fly. So the redundancy theory doesnít say that whatever anyone says is true. What it does say is that, if I say something, then Iím committed to saying that what I said is true.
And this makes some sense. Suppose, on the one hand, I say, "God exists! There is a supreme being!" Then suppose on the other hand that I say, "Itís true that God exists! Itís true that there is a supreme being!" Have I added anything to my original claim when I say that itís true? I mean, have I added anything other than emphasis and a declaration that I really do believe what Iím saying? The redundancy theory thinks not; saying that something is true is only adding emphasis.
But some people disagree. They think that there is something that the redundancy theory is missing. They think thereís got to be some reason why we came up with this word "true." The redundancy theory says basically that itís only a term of emphasis. But is that really all it is? Isnít the idea, rather, that one specifically wishes to point to the fact that a proposition bears some relation to reality -- correpondence, describing the facts, something like that. Well, weíre not going to resolve that dispute now. The dispute quickly becomes very technical and draws a lot on results and problems in logic.
So instead letís take a quick look at another theory of truth, that differs quite a bit both from the correspondence theory and the redundancy theory. This is called the coherence theory. The coherence theory offers another definition of "truth." It says that truth depends on coherence, as follows:
It is true that P iff P is part of a coherent system of propositions.
Roughly, P is true if it coheres with a system of propositions that itís part of. Typically a "system of propositions" is understood as a group of propositions that some one person believes. So if you like, you can think of "system of propositions" as meaning a belief system. Then the idea is that if your belief system is coherent, then your beliefs are true. And if you come across a belief that doesnít cohere with the others, then you can toss it out as incoherent and thus false.
I am not going to try to give an example of a coherent system or a belief that is true because it is part of the system. The reason Iím not isnít that I think the coherence theoryis obviously wrong, but because the coherence theory is better regarded, in my opinion, as a theory about justified belief, that is, when beliefs are justified or rational, which is something we are going to study when we study epistemology. The coherence theory is better regarded as a theory about when beliefs are justified than as a theory about when beliefs are true. Thatís my claim, anyway -- Iím telling you this only so you can understand why weíre not examining the theory in any depth right now. But when we look at the coherence theory of justification, I will give examples and criticisms that apply to coherence theories generally -- whether of truth or of justification.
Iíll conclude our discussion of theories of truth by presenting a theory which was introduced and made by American philosophers, Charles Pierce (pronounced "purse") and William James, in the late 19th and early 20th centuries. Their theory is called pragmatism, or the pragmatic theory of truth. Pragmatism has been regarded as an American theory of truth, although I would suggest that the correspondence theory probably more closely reflects the commonsense realism that most Americans share. Anyway, "pragmatism" is one of those neat words that philosophers like so much that they want to appropriate it for themselves, without regard to how it has been used before. As a result, the term "pragmatism" means a lot of different things to a lot of different people; there are lots of versions of pragmatism. So let me talk anyway about one very important, influential version, that is due to Peirce, and which has received some renewed interest from some philosophers today, like Richard Rorty and Hilary Putnam.
Here is Peirceís version, roughly stated:
It is true that P iff P is agreed upon in the consensus achieved at the ideal limit of inquiry.
Peirce invites us to imagine what science will be like a few hundred, or perhaps a few thousand years from now. He predicted that human inquiry and truth-seeking would, or at the very least could, at some point come to an end, a limit; there would, he thought, be basically no questions left to be answered, and the state of human knowledge could not be improved upon. At that point there would be, he thought, some very general consensus, firmly agreed-upon, by all inquirers. And if some proposition now being considered would be something that everyone would agree on, in that ideal limit of inquiry, then that proposition is true. And thatís what it means to say that a proposition is true: that it is part of the consensus that would exist in the ideal limit of inquiry.
I think you might be able to see some reason for accepting pragmatism. Much of the motivation behind it comes from the thought that the truth is knowable. I mean, suppose you thought that: if something is true, then it can be known to be true. Then what, really, is knowability? Well, something would be knowable if it could be known -- if not now, then by someone, somewhere down the road. So something is knowable if we could, after long hard careful inquiry, discover it. In yet other words, something is knowable if we would know it in the ideal limit of inquiry.
Now, suppose you thought that all truth is knowable in this sense. In that case, everything that could be known, would be known in the ideal limit of inquiry. In the perfect science all truths would be known. There wouldnít be any truths left over. So then why not say that there is no more to truth than that what that perfect science would tell us? That would simplify matters. There would be no need to look for any sort of correspondence between propositions and the world, or between propositions and a coherent system of propositions. Truth, since it is knowable, is whatever the perfect science would tell us in the ideal limit of inquiry. In that way pragmatism is very optimistic.
Iíll raise, rather briefly, two basic objections that can be made to pragmatism. First, you can say: maybe there are some truths that arenít knowable. Why think that every proposition must be knowable? Why not say there are some true propositions that we canít ever know, not even in some ideal limit of inquiry? Let me give you an example. There are probably complex processes going on inside of black holes; but black holes are so gravitationally powerful that not even light can escape from them. So we could not possibly get knowledge of some specific events going on, right now, inside some black hole. Nonetheless there would seem to be some facts there; scientists might even know enough to be able to describe what might be going on; the point, though, is that they canít confirm that it is going on, even if they can describe, in generalities, what might be going on. So the first problem for pragmatism is that it certainly appears that there are some truths that would not appear in the perfected science in the ideal limit of inquiry -- because they cannot be known at all. You can probably think of more examples yourself; maybe truths about what went on in the minds of people long dead, or facts about very distant events. Perhaps there are facts about subatomic particles which we cannot, in principle, ever know.
Hereís a second objection. Basically, what pragmatism describes an indicator or a sign of truth. It really cannot be regarded as a theory of the meaning of the word "true." Do you see the difference? Thereís a difference between stating an indicator and giving the meaning. For example, when the streetlights turn at the end of a day, thatís an indicator, a sign, that evening is coming on. It would be an obvious mistake to say that the word "evening" just means "the time that the streetlights turn on." In the same way, while it might be an indicator of truth, that a proposition is part of that perfect science at the ideal limit of inquiry, that just isnít what "truth" means.
This present objection isnít so much an argument against pragmatism, so much as it is a request -- that we make sure that we arenít confusing an indicator of truth with the meaning of the concept truth. There is a difference between the two and it seems to me that pragmatism confuses them. Anyway, I think a more powerful objection is lurking about here. But we donít have time to go into it in any further detail.
I think that after this very brief discussion of theories of truth, the revised correspondence theory looks most plausible; but we just havenít discussed them in enough depth for me to be able to say that with any certainty. But as usual you have been introduced to the terrain: among different theories of truth there are the correspondence theory, the redundancy theory, the coherence theory, and pragmatism. With such a variety to choose from at the very least you should be convinced that you donít have to rest content with any sort of relativism that says that truth is just the same as belief. You can do a heck of a lot better than that.