"There are no truths" cannot be true. Therefore there must be at least two, that sentence and this one.
The purpose of this post is to distinguish two uses of "true", one functional, implicit and necessary for communication, and another use, ordinary and commonly discussed albeit logical, metaphysical and theoretical and ... unnecessary and maybe even undesirable.
A friend, arguing that theories have value beyond their truth, asks me to set truth aside when evaluating a theory. He likes to entertain post modernist ideas.
I ask, in a Pinker mood, do you think it's true that theories have value beyond their truth? You said so, but if we are to set truth aside, what am I supposed to think you believe when you say, "theories have value beyond their truth"? If I'm not to believe that you think this is true, then what am I supposed to conclude about what you're saying? Why should I even try to understand or credit it? Why are you even talking to me? Why should I listen?? To enjoy the sound of your voice???
Stephen Pinker makes much of this basic universal necessity of truth to criticize the post modernists and the Nietzsche-chic. He's partly right. Partly.
The notion of truth in the little conversation above is playing two different roles accomplishing two different kinds of work. One is communicative, functional and procedural. In order to converse, there must be an assumption of truth to the assertions intended by the conversants. Assuming otherwise defeats the purpose of conversational exchange of information. Abandoning that assumption of truth-intention also lands the conversants in a liar paradox from which conversation can go nowhere.
That process-functional use of truth is usually not spoken, since it's a prior assumption of any meaningful conversation. H. Paul Grice called this conversational cooperation. If you're looking for a beautiful, powerful and revelatory theory, read his two papers on the logic of conversation or the sections of Larry Horn's Natural History of Negation dealing with implicature. Although Grice does not discuss them, even greetings have an assumption of cooperativeness, since they carry a meaning of agreeableness or friendliness or at least politeness. All cooperative. But even when we get into a heated argument, we still do it in a shared language! And because? Because we want agreement or respect or submission -- something from the other. That's a social species. Even our bickering is cooperative in this needy way. When social scientists describe our species as a cooperative one, language use is not always their first example, but it should be.
So there's this practical, functional, process use of truth -- to oil the gears of information exchange, really the catalyst without which conversational information exchange wouldn't work. Without it language would never have evolved. Assuming everyone talking to you is lying, what survival benefit would you gain from listening to idle, useless noise? Language could only evolve if the exchange of information were useful and believed.
This practical use of truth is not generally expressed. " 'My name is jones', is true." Those last two words are a waste of breath. "My name is 'jones' " would suffice. Its assertion of truth is part of the conversational function itself.
This communicative use of truth is a mere convenience with no grand metaphysical or scientific import, but a necessary convenience nonetheless.
The other use of "true" is the one we most often talk about when we talk about truth and truths. It gets a lot of attention because it's louder than the tacit assumed one. It's a logical or philosophical notion, not just a practical one, and it's not a function of a process. It pops up not only when you want to talk philosophy and logic, but also in disputes over facts and disputes over the content of other people's assertions. You could call this the evaluative use of "true" or explicit use. A Wittgensteinian might call this philosophical truth, abusing language outside the practical game for which it is useful.
The explicit use though familiar, is metaphysical. "That's true" implies 'that's real', 'that exists', 'I agree that's real' or 'yes, that exists'. It's essential to how we perceive and understand. It's not only metaphysical, defining reality and existence, but it's also epistemic, defining what we think we know and agree to. You can see how different this is from the tacit conversational use. This philosophical use of "true" to indicate "reality" or "existence" -- all very metaphysical. The functional use belongs very much in the interactive world, not of metaphysics or the assessment of facts, but of pursuing the process of informational exchange.
It's worth pointing out, as an aside, that "Truth" is widely taken as a mystery. This appears to be yet another mix up. Facts, what's actually true of the world, is a mystery -- science approaches it but never quite perfectly or completely. Look at the immense lure of quantum physics. That's full of mystery. The world is full of mystery from its start, from its base to its top and in every direction. Maybe for that reason people, especially in religions ("I am the Truth" and "What is truth?), truth itself is viewed as a mystery. Actually truth itself is quite a simple and boring property. It's a property of assertions and that's it. "The Empire State Building is on 14th Street" is false; "The Empire State Building is on 34th Street" is true. Is the Empire State Building true? That's a confused question. Things are not true or false and even words alone are not true or false. Only assertions get to be true or false. "I am the Truth" is a figure of speech, intended to mystify. "'I am the son of God' is true" is an assertion, and it could be true or false. "I am the Truth" taken literally, is just incoherent, albeit poetic and mysteriously impressive as well as conveniently ambiguous. Does it mean, believe that I'm god? Or, you should follow what I do? Or something even more abstract about the universe and all of experience? All of the above, probably. It's the beautiful poetry of religion. My favorite poetry is the poetry that I can grasp sort of but can't entirely understand. Mystery is the intellectual gift that keeps on giving. Never grasped, never spent. Ever luring.
The two uses emerge from different motives and sources. They belong to different human processes. One is necessary for communication, although the tacit assumption can be questioned: "you don't really believe that, do you?" And because it is a kind of interactive game, as with game rules, it's not up to the individual whether to use it while playing. On the other hand, the metaphysical truth isn't necessary at all. It's a contention of the individual who asserts it.
Steven Pinker vociferously objects to the popular post modernist, Nietzschean rejection of truth. He wrote a book about it. But it seems to me that he doesn't give enough credibility (a word essentially tied to truth) to falsehoods. :)
Going back to the top, my friend and I were discussing what makes a theory good. His answer was "It's good if it works. A theory can have value beyond truth." For example, a sociologist or a Straussian might assert that a community's religion promotes social cohesion and individual psychological health. The truth of the religion plays no role there.
Or the Pope might say "God is good" whether he believes it or not, whether it's true or not or even if there's a god or not. And he may assert that it is true, again even if it's not and he knows it's not. Does his audience assume that he believes what he says? Not necessarily. I often think he doesn't really believe any of the hocus pocus and he knows that many of his followers don't either. The conversational cooperative assumption of truth has been slightly shifted to a pretense of truthfulness. It's all a communal dance of mutual convenience, not metaphysical truth. The priority is the community, not its truth. Similarly, Donald Trump often doesn't seem to expect anyone to believe some of his patent falsehoods. It's more cheer-leading his supporters than arguing over facts. Who cares about facts? It's about the Us team.
The Pope example may seem a stretch, but as AI spreads along with conspiracy theories, such deceitful conveniences may become the rule. Does anyone believe propaganda? Does anyone believe the alternative conspiracy theories? There was a time when information about health, for example, was univocal (saturated fat and cholesterol are bad) and everyone believed it. Now there is so much contradictory information about health that no one knows what to think or do, hence the unbounded proliferation of health advice. So what should people believe, or how should they decide? Whatever my friends believe? And what do they believe? The YouTube influencer who seems grooviest to them? It's not about truth but identity, trend and social fashion signals.
Here's where my friend has a point, a qualified point. Our sophisticated Pope thinks the theory he publicly espouses is a good one even if it's false. And that's true even if he assumes that his sophisticated audience likewise thinks the theory is good but false.
The answer to "what makes a theory a good theory?" is yet another question "good for what?" And it's this qualification that brings us back to truth. How do you assess what is good without a notion of truth? You say "faith" is good. How do you defend that? "It's good for the community" is a sound answer only if that answer is true. Whatever the defense, it'll depend on truth, or something close to truth like high probability. All kinds of lies may be good, but if they are good, then "they are good" must be true in the metaphysical sense about them, or at least, in a world where there are no absolute certainties, most likely to be true. (The post "entropy and truth" explains the role of probability in theoretical "truth".)
It seems to me that the only way around this moral necessity of "true" is another process, the process of ignoring it. Humans believe all sorts of things with little defense or question. And we still function individually and socially. Sometimes, maybe even often, ignoring truth (or high probability) is essential and necessary in the process of functioning. Those who have an accurate assessment of themselves tend to be unhappier and less successful than those who hold unwarranted, false confidence in themselves.
This feeds a question discussed in another post "academicism versus activism". There is an essential value of truth-seeking for any academic. But that ivory tower is an isolated place of observation. The rest of the world we actually live in is a world of choices and actions. What's more, it's overrun with others' competing choices and actions, interests, movements, forces, militaries, power plays in a social context of inequalities of influence, and within those inequalities classes that are served by those militaries local or national, and classes that are not so served, those that "the law protects but does not bind" and those that "the law binds but does not protect".
In such a world, expressing truth is not always the priority choice. Propaganda holds an institutional microphone with big speakers to defend and justify itself. On the socio-political stage, the oppressed must state their interests as loudly as they can, otherwise their side of the truth won't be heard and the only means of getting any play will be forceful actions alone. And there are multiple interpretations to any event or any circumstance (see "true but wrong" and "the questions you ask determine the answers you get"). Deciding which is true can't even depend on the inhabitants of the ivory tower, since science is an ongoing investigation, not a body of truths, and scientists have no crystal ball. The players in the world of unequal influence promote interests, the truths they promote serve those interests, not the truth-for-truth's-sake of the academic.
So there are two very different roles of "true". One works in the game of communication and is an indispensable rule of that game. The other is essential for the academic process of research (though it should be probability, not truth, see the "entropy and truth" post), but not everywhere outside the ivory tower where wealth and influence rule regardless of truth.
[Of course, the Ivory Tower is also pressured by outside funding and inside biases. The professional class outside the sciences often underestimates these pressures, assuming scientists to be objective and incorruptible, while the conspiracy theorists overestimate them as if every scientist were morally inferior to them.]
These two common uses of "truth" or "true" are often not clearly distinguished by users or even by philosophers interested in truth or even Stephen Pinker who uses the necessity of one to try to prove the necessity of the other. Usually the focus is on the one or the other, not both, so one is forgotten in favor of the other. All uses of "truth" are linguistic -- it's a word and it applies to linguistic assertions, not to non linguistic things -- but one of the uses involves as well a lot of metaphysics and ontology. The conversational use is not metaphysical, it's practical. The metaphysical one might not be necessary; the conversational one is. It's one of the rules of the game, the sine qua non of the game.
