Truth Lies at the Bottom of a Well

I was delighted to come across this awesome example of Academic art the other day, which sent me scrabbling across the Internet:

It's called Truth Coming Out of Her Well to Shame Mankind, by our old favourite Jean-Leon Gerome (1824-1904). Truth is not just going to shame Mankind - she's going to give us all hell with the scourge in her right hand there.

And I thought ... what the heck? Why is Truth living down a well?

It seems to originate with a quote from Democritus:

ἐτεῇ δὲ οὐδὲν ἴσμεν, ἐν βυθῷ γάρ ἡ ἀλήθεια: "We know nothing certainly, for truth lies in the deep."

or in fuller form:

"By convention hot, by convention cold, but in reality only atoms and void, and also in reality we know nothing, since the truth lies in the deep."

"In the deep" suggests under water, somewhere completely inaccessible, and is sometimes glossed as "beneath the sea":  But by the looks of things it was commonly quoted by Victorian times as "at the bottom of a well" and had gained the connotation that it is something you have to dig down a long way for. When used in specific cases - "The truth of the matter is something we'll probably never know."

Édouard Debat-Ponsan: Truth Leaving the Well (1898)

Frances MacDonald McNair: Truth Lies at the Bottom of a Well (1912)

We don't quote Greek philosophers in public much these days, which is possibly a great loss to art.