Hamlet Act IV scene iii
Hamlet: A man may fish with the worm that hath eat of a king, and cat of the fish that hath fed of that worm.
Claudius: What dost you mean by this?
Hamlet: Nothing but to show you how a king may go a progress through the guts of a beggar.
"Lovers and madmen have such seething brains,
Such shaping fantasies, that apprehend
More than cool reason ever comprehends.
The lunatic, the lover, and the poet,
Are of imagination all compact:
One sees more devils than vast hell can hold —
That is the madman;
The lover, all as frantic,
Sees Helen’s beauty in a brow of Egypt.
The poet’s eye, in a fine frenzy rolling,
Doth glance from heaven to earth, from earth to heaven;
And, as imagination bodies forth
The forms of things unknown, the poet’s pen
Turns them to shapes, and gives to airy nothing
A local habitation and a name.
Such tricks hath strong imagination,
That, if it would but apprehend some joy,
It comprehends some bringer of that joy;
Or, in the night, imagining some fear,
How easy is a bush suppos’d a bear."
- Theseus (A Midsummer Night’s Dream, Act V scene i)
(Source: dailyshakespeare, via dailyshakespeare)