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.

Excerpt from A Defence of Poetry, Percy Bysshe Shelley (1792 – 1822)