This may be off topic but when discussing truth, I am always reminded of Aristotle's intellectual virtues. We can only know the truth about matters that cannot be otherwise or things that are ‘by necessity’ (these concern the virtue of scientific knowledge or episteme, according to Aristotle). Politics and human actions in general are always interpretable and contingent, so they fall outside episteme. Practical wisdom, or phronesis, is essential in matters concerning meaning and how to live well. So, in politics we should be concerned about what is meaningful and beneficial to the relevant parties, rather than what is true. Many modern paradoxes arise from the confusion between truth and meaning. Kant, Heidegger, and Arendt followed Aristotle in their approaches to truth and meaning. They believed that questions concerning truth are matters of knowing/intelligence/science, while questions concerning meaning are matters of reason/understanding and, hence, concern politics, ethics and other ‘interpretable’ activities. The caveat is that these three thinkers understood reason and intelligence to be different intellectual capacities. Anyway, according to the above, there is no policy or action that is true. Questions about truth are not up for debate. Hannah Arendt expressed it most succinctly: “To anticipate, and put it in a nutshell: The need of reason is not inspired by the quest for truth but by the quest for meaning. And truth and meaning are not the same. The basic fallacy, taking precedence over all specific metaphysical fallacies, is to interpret meaning on the model of truth.” (The Life of the Mind, p. 15)
Green is green once we know it. But is it true? What if we were taught colors mixed up? Well, eventually we would be taught the error of our ways. This is the way even the scientific ‘truths’ work. Always open to revision, sometimes only after all the old ‘believers’ are dead.
The Roman satirist Juvenal has a clear-eyed answer to your excellent question, how do we know what's true? The answer he implies is "cross examination!" And his favorite test case is the outlandish stories Odysseus tells in Odyssey 9-11. Here's the relevant text from A.S. Kline's translation here: https://www.poetryintranslation.com/PITBR/Latin/JuvenalSatires15.php
When Ulysses told the
Tale of such a crime [viz. cannibalism], at the dinner table, to startled Alcinous,
Some of his listeners must have been moved to anger, or to
Laughter even, thinking him a fluent liar. ‘Return him to the
Waves, why don’t you? He’s earned the reality of some cruel
Charybdis, by inventing his Cyclopeans, and Laestrygonians.
I’d sooner believe in his Scylla, or his clashing Cyanean rocks,
His bag of winds, or his Elpenor, grunting beside his fellow
Oarsmen, turned to swine by a delicate touch of Circe’s wand.
Does he think we Phaeacians are as empty-headed as that?’
It’s what he’d have cried, rightly, some sober man of Corcyra,
One who’d restricted his intake of wine from the brimming jar;
Since Odysseus, after all, had not a single witness to his story.
Unlike many readers today, ancient readers simply took it for granted that Odysseus was lying all through the most famous part of the Odyssey! You can find the same interpretation in Lucian (I'd have to check notes to see where, but it's there). After all, Homer says right at the start that the "idiots" (nepioi) died because they ate the oxen of the sun. But that ain't what Odysseus tells Alcinous and Arete when he's looking for a lift home, though. And since nobody was there to contradict him, hey -- why not?
This may be off topic but when discussing truth, I am always reminded of Aristotle's intellectual virtues. We can only know the truth about matters that cannot be otherwise or things that are ‘by necessity’ (these concern the virtue of scientific knowledge or episteme, according to Aristotle). Politics and human actions in general are always interpretable and contingent, so they fall outside episteme. Practical wisdom, or phronesis, is essential in matters concerning meaning and how to live well. So, in politics we should be concerned about what is meaningful and beneficial to the relevant parties, rather than what is true. Many modern paradoxes arise from the confusion between truth and meaning. Kant, Heidegger, and Arendt followed Aristotle in their approaches to truth and meaning. They believed that questions concerning truth are matters of knowing/intelligence/science, while questions concerning meaning are matters of reason/understanding and, hence, concern politics, ethics and other ‘interpretable’ activities. The caveat is that these three thinkers understood reason and intelligence to be different intellectual capacities. Anyway, according to the above, there is no policy or action that is true. Questions about truth are not up for debate. Hannah Arendt expressed it most succinctly: “To anticipate, and put it in a nutshell: The need of reason is not inspired by the quest for truth but by the quest for meaning. And truth and meaning are not the same. The basic fallacy, taking precedence over all specific metaphysical fallacies, is to interpret meaning on the model of truth.” (The Life of the Mind, p. 15)
Green is green once we know it. But is it true? What if we were taught colors mixed up? Well, eventually we would be taught the error of our ways. This is the way even the scientific ‘truths’ work. Always open to revision, sometimes only after all the old ‘believers’ are dead.
Never got over Zeno's Paradoxes as far as the truth goes.
The Roman satirist Juvenal has a clear-eyed answer to your excellent question, how do we know what's true? The answer he implies is "cross examination!" And his favorite test case is the outlandish stories Odysseus tells in Odyssey 9-11. Here's the relevant text from A.S. Kline's translation here: https://www.poetryintranslation.com/PITBR/Latin/JuvenalSatires15.php
When Ulysses told the
Tale of such a crime [viz. cannibalism], at the dinner table, to startled Alcinous,
Some of his listeners must have been moved to anger, or to
Laughter even, thinking him a fluent liar. ‘Return him to the
Waves, why don’t you? He’s earned the reality of some cruel
Charybdis, by inventing his Cyclopeans, and Laestrygonians.
I’d sooner believe in his Scylla, or his clashing Cyanean rocks,
His bag of winds, or his Elpenor, grunting beside his fellow
Oarsmen, turned to swine by a delicate touch of Circe’s wand.
Does he think we Phaeacians are as empty-headed as that?’
It’s what he’d have cried, rightly, some sober man of Corcyra,
One who’d restricted his intake of wine from the brimming jar;
Since Odysseus, after all, had not a single witness to his story.
Unlike many readers today, ancient readers simply took it for granted that Odysseus was lying all through the most famous part of the Odyssey! You can find the same interpretation in Lucian (I'd have to check notes to see where, but it's there). After all, Homer says right at the start that the "idiots" (nepioi) died because they ate the oxen of the sun. But that ain't what Odysseus tells Alcinous and Arete when he's looking for a lift home, though. And since nobody was there to contradict him, hey -- why not?