excerpts from A Defence of Poetry

(PERCY BYSSHE SHELLEY)

According to one mode of regarding those two classes of mental action, which are called reason and imagination, the former may be considered as mind contemplating the relations borne by one thought to another, however produced; and the latter, as mind acting upon those thoughts so as to colour them with its own light, and composing from them, as from elements, other thoughts, each containing within itself the principle of its own integrity.

Reason is the enumeration of quantities already known; Imagination is the perception of the value of those quantities, both separately and as a whole. Reason respects the differences, and Imagination the similitudes of things. Reason is to Imagination as the instrument to the agent, as the body to the spirit, as the shadow to the substance.

Poetry, in a general sense, may be defined to be "the expression of the Imagination:" and Poetry is connate with the origin of man. Man is an instrument over which a series of external and internal impressions are driven, like the alternations of an ever-changing wind over an Æolian lyre; which move it, by their motion, to ever-changing melody.

For language is arbitrarily produced by the Imagination and has relation to thoughts alone; but all other materials, instruments and conditions of art, have relations among each other, which limit and interpose between conception and expression...We have thus circumscribed the meaning of the word Poetry within the limits of that art which is the most familiar and the most perfect expression of the faculty itself.

A man, to be greatly good, must imagine intensely and comprehensively; he must put himself in the place of another and of many others; the pains and pleasures of his species must become his own. The great instrument of moral good is the imagination; and poetry administers to the effect of by acting upon the cause. Poetry enlarges the circumference of the imagination by replenishing it with thoughts of ever new delight, which have the power of attracting and assimilating to their own nature all other thoughts, and which form new intervals and interstices whose void for ever craves fresh food.

We want the creative faculty to imagine that which we know; we want the generous impulse to act that which we imagine; we want the poetry of life: our calculations have outrun conception; we have eaten more than we can digest.

A man cannot say, "I will compose poetry." The greatest poet even cannot say it: for the mind in creation is as a fading coal which some invisible influence, like an inconstant wind, awakens to transitory brightness...when composition begins, inspiration is already on the decline.