We Are Masters of our Dreams and Delusions: Lucretius, DRN 4.453-468

“When sleep has conquered our limbs with sweet rest
And our whole body lies in the deepest slumber,
Then our limbs still watch and seem to move
And there in the blind darkness of night we think
We see the sun and the light of day
And instead of our confined space we think
We have the sky, sea, rivers and mountains under our feet
And we hear their sounds, though the cruel silence of night
Hangs everywhere, we speak while staying silent.

We see many marvels beyond this kind
That try to break the faith of our senses
But they do not, since the greatest of them fail
On the opinions of the mind, things we have provided ourselves,
Visions are seen which have not been seen by our senses.
Nothing is more difficult than to separate obvious things
From the dubious, once your own mind has provided them.”

Denique cum suavi devinxit membra sopore
somnus et in summa corpus iacet omne quiete,
tum vigilare tamen nobis et membra movere
nostra videmur, et in noctis caligine caeca
cernere censemus solem lumenque diurnum,
conclusoque loco caelum mare flumina montis
mutare et campos pedibus transire videmur,
et sonitus audire, severa silentia noctis
undique cum constent, et reddere dicta tacentes.
Cetera de genere hoc mirande multa videmus,
quae violare fidem quasi sensibus omnia quaerunt,
ne quiquam, quoniam pars horum maxima fallit
propter opinatus animi, quos addimus ipsi,
pro visis ut sint quae non sunt sensibus visa;
nam nihil aegrius est quam res secernere apertas
ab dubiis, animus quas ab se protinus addit.