What do we mean by truth and falsehood?

Truth goes naked when Falsehood wears Truth’s clothing.

A poetic clue …

“Truth,” said a traveller
poem by Stephen Crane
(1905)

“Truth,” said a traveller,
“Is a rock, a mighty fortress;
Often have I been to it,
Even to its highest tower,
From whence the world looks black.”

“Truth,” said a traveller,
“Is a breath, a wind,
A shadow, a phantom;
Long have I pursued it,
But never have I touched
The hem of its garment.”

And I believed the second traveller;
For truth was to me
A breath, a wind,
A shadow, a phantom,
And never had I touched
The hem of its garment.

Ancient Fables

A few thousand years ago a man went traveling through a rough country with no roads, or paths, or any evidence that any people had been there before him; suddenly he encountered Veritas. Startled the man asked “Venerable lady why do you live in this wilderness far from the company of people?” Veritas replied “Among the people of old, lies were found among only a few, but now they have spread throughout all of human society!”

How Truth came to be naked … Truth and Falsehood went for a swim and a bath in cool waters one hot Summer day thousands of years ago. Falsehood emerged from the water first and dressed in Truth’s clothing. When Truth came out of the waters she found her clothing gone; refusing to wear clothing that did not belong to her she went naked from that day on …

In the time of Rome’s Empire Veritas was thought to hide in a Holy Well

 … Truth seemed rare, not commonly found, yet sacred …

The Problems of Philosophy

TRUTH AND FALSEHOOD

“Our knowledge of truths, unlike our knowledge of things, has an opposite, namely error. So far as things are concerned, we may know them or not know them, but there is no positive state of mind which can be described as erroneous knowledge of things, so long, at any rate, as we confine ourselves to knowledge by acquaintance. Whatever we are acquainted with must be something; we may draw wrong inferences from our acquaintance, but the acquaintance itself cannot be deceptive. Thus there is no dualism as regards acquaintance. But as regards knowledge of truths, there is a dualism. We may believe what is false as well as what is true. We know that on very many subjects different people hold different and incompatible opinions: hence some beliefs must be erroneous. Since erroneous beliefs are often held just as strongly as true beliefs, it becomes a difficult question how they are to be distinguished from true beliefs. How are we to know, in a given case, that our belief is not erroneous? This is a question of the very greatest difficulty, to which no completely satisfactory answer is possible. There is, however, a preliminary question which is rather less difficult, and that is: What do we mean by truth and falsehood? It is this preliminary question which is to be considered in this chapter. In this chapter we are not asking how we can know whether a belief is true or false: we are asking what is meant by the question whether a belief is true or false. It is to be hoped that a clear answer to this question may help us to obtain an answer to the question what beliefs are true, but for the present we ask only ‘What is truth?’ and ‘What is falsehood?’ not ‘What beliefs are true?’ and ‘What beliefs are false?’ It is very important to keep these different questions entirely separate, since any confusion between them is sure to produce an answer which is not really applicable to either.”
— Bertrand Russell