In Act Five, Scene One of A Midsummer Night’s Dream, Theseus discusses (with some disdain) the concept of imagination and fantasy:
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 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 supposed a bear!
this, to my ear, sounds fairly positive, but Theseus doesn’t think so… not with such stories being “More strange than true” (V.i.2)
Theseus begins linking lovers and madmen to imagination, which gives each type of man “seething brains.” We then get a set of linked concepts via apprehend/comprehend (two sets, actually, bookend the speech as a whole). According to the Oxford English Dictionary Second Edition on CD-ROM (v. 4.0), “apprehend” has a number of possible meanings, but the one that fits best here is “To feel emotionally, be sensible of, feel the force of”; “comprehend,” too, has a number of definitions, but the one that works best is “To grasp with the mind, conceive fully or adequately, understand” (OED). So these “seething brains” can feel more than what the cool rationality of the mind can understand.
Theseus then goes on to add the poet to lovers and madmen, as those who are “composed of” (OED) imagination (“of imagination all compact”). He dispatches his old targets with quick line-and-a-half toss-offs each: the madman is filled with paranoia, the lover — “affected with mental disease, lunatic, insane; in later use, violently or ragingly mad” (“frantic”: OED) — sees beauty in the (racist) non-beautiful. Theseus then moves on to his new target: the poet.
The poet’s eye rolls in “mental derangement; delirium, or temporary insanity” (“frenzy”: OED), and sees the “forms of things unknown”… something not known (by reason), but felt (in emotion). The poet can turn these “to shapes” and give them a “name” or words. What’s more is that the poet’s pen also gives these “airy nothing(s) // A local habitation”: “A place of abode or residence: either the region or country inhabited” (OED). Not only does the poet give these fantasies a name, but also a HOME, a place in the real world.
Only “strong imagination,” Theseus claims, can make these things happen. Additionally, imagination has the ability to create (“apprehend”) not just the emotion (“joy” or “fear”), but to conjure into reality (“comprehend”) the “bringer” of that emotion. This is a crazy and foolish concept for Theseus, and yet his words belie a less negative view of imagination.
Notice that the time — the number of lines — spent by Theseus on “the poet” is between two and four times that which he spends on the lover and the madman. While Theseus may have little or no respect for those who are comprised of imagination, it’s obvious that the person putting those words in his mouth, does… especially for the poet.
Shakespeare the poet, in A Midsummer Night’s Dream, fashions a play on the power of imagination — after all, isn’t the pansy potion really just a catalyst for fantasy and imagination? — (this is the emotion); he also gives us the “bringer” of that notion and/or emotion, the mouthpiece through which these concepts are given the most explicit statement: Theseus.