What is truth?

1. The Truth is... a riddle

What is something that humans seek, and don't know it when they see it?

The answer is the truth!

(C.f. Jacobellis v Ohio 1964 in which the judge declined to define hard-core pornography, but famously said "I know it when I see it".)

2. The Truth is... not known

 

The conundrum of seeking truth but not knowing it when we see it is embedded in the idea of knowledge as justified true belief. 

It is said that we know something to be true if 

    (a) we believe it to be true, 

    (b) we have justification for our belief, and 

    (c) it is true.

We can build towards knowledge 

with beliefs and justifications, 

but we fail unless it's true.

And how do we "know" if it's true? 

 

Whether something is true is... unknown. 

Frustrating! 

3. The Truth is... out of reach

Truth is a destination that can never be reached.

rather like the end point in Zeno's paradox.

To get to our destination, 

we can agree that we must travel half the distance 

from our starting point to the end point, 

then half the distance from halfway to the end point, 

and then half the remaining distance, 

and so on,

ad infinitum.

And therein lies the problem:

we approach,

but we never reach.

We get closer to truth,

or at least we think we do,

but we never arrive,

or do not know if we do.

Pursuing truth is like pursuing the horizon.

(Neil Gaiman used the metaphor in 

talking of the pursuit of perfection).

And thinking of horizons ...

4. The Truth is... relative

People once thought of the world as flat

and there is still, to this day, 

compelling evidence of that idea.

Spend some days at sea, 

and every day, the world looks as if it is flat.

Of course there are images from out in space

showing the world is round.

So what is true?
What I see with my own eyes: flat?
Or what I see in images shown to me by others: sphere?

Is the evidence supplied by the device of another
truth or an artifact?
Galileo faced this problem when

proving the existence of Jupiter's moons

by sightings through his telescope.

Regardless,
the truth is...

the world isn't actually flat,

and it isn't a sphere either.
But both serve as good approximations
in certain circumstances.

For throwing a ball, 

believing the world is flat 

works;

For throwing a satellite, 

believing the world is a sphere 

works;

However, if you're flying a plane, 

starting at 1000' above sea-level;

treat it is flat, you'll fly into space,

treat it as spherical, you'll fly into mountains.

As Einstein showed (vis-a-vis Newton),
The truth is relative,

5. The Truth is... accessed indirectly

Seeing truth is like glimpsing a star 

in your peripheral vision,

If you look at it directly,

you cannot see it.

The truth is visible

in the twilight of my awaking,

but is gone by the time 

I open my eyes
let alone search for pen and paper.

It is like the answer to the riddle

which goes like this:

You are faced by two doors

one door leads to heaven 

the other to hell.

In front of the two doors

are two people who know which is which.

One person always tells the truth,  

the other always tells lies,

but you don't know which is which.

You can ask but ONE question of ONE guard.

What is your question?

The question that solves the riddle*
reveals the truth,

but not directly.

The answer to your question 

gives not the truth,

but a means to find the truth!

6. The Truth is... a paradox

- - - - - - - - - - - - - - - - -

 

* [SPOILER ALERT: This is the solution to the riddle asked at #5]
"If I was to ask the other person which is the door to heaven, which one would they point to?"
And the door that your interlocutor points to is actually the door to hell. You want to go through the other door, the one that they did not point to!