Lucretius, De Rerum Natura
William Ellery Leonard, Ed.

     Again, if one suppose
That naught is known, he knows not whether this
Itself is able to be known, since he
Confesses naught to know. Therefore with him
I waive discussion- who has set his head
Even where his feet should be. But let me grant
That this he knows,- I question: whence he knows
What 'tis to know and not-to-know in turn,
And what created concept of the truth,
And what device has proved the dubious
To differ from the certain?- since in things
He's heretofore seen naught of true. Thou'lt find
That from the senses first hath been create
Concept of truth, nor can the senses be
Rebutted. For criterion must be found
Worthy of greater trust, which shall defeat
Through own authority the false by true;
What, then, than these our senses must there be
Worthy a greater trust? Shall reason, sprung
From some false sense, prevail to contradict
Those senses, sprung as reason wholly is
From out the senses?- For lest these be true,
All reason also then is falsified.
Or shall the ears have power to blame the eyes,
Or yet the touch the ears? Again, shall taste
Accuse this touch or shall the nose confute
Or eyes defeat it? Methinks not so it is:
For unto each has been divided off
Its function quite apart, its power to each;
And thus we're still constrained to perceive
The soft, the cold, the hot apart, apart
All divers hues and whatso things there be
Conjoined with hues. Likewise the tasting tongue
Has its own power apart, and smells apart
And sounds apart are known. And thus it is
That no one sense can e'er convict another.
Nor shall one sense have power to blame itself,
Because it always must be deemed the same,
Worthy of equal trust. And therefore what
At any time unto these senses showed,
The same is true.