Perhaps no person can be a poet, or can even enjoy poetry, without a certain unsoundness of mind, if anything which gives so much pleasure ought to be called unsoundness.  By poetry we mean not all writing in verse, nor even all good writing in verse.  Our definition excludes many metrical compositions which, on other grounds, deserve the highest praise.  By poetry we mean the art of employing words in such a manner as to produce an illusion on the imagination, the art of doing by means of words what the painter does by means of colours.  Thus the greatest of poets has described it, in lines universally admired for the vigour and felicity of their diction, and still more valuable on account of the just notion which they convey of the art in which he excelled: 

“As the 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.”

These are the fruits of the “fine frenzy” which he ascribes to the poet—­a fine frenzy doubtless, but still a frenzy.  Truth, indeed, is essential to poetry; but it is the truth of madness.  The reasonings are just; but the premises are false.  After the first suppositions have been made, everything ought to be consistent; but those first suppositions require a degree of credulity which almost amounts to a partial and temporary derangement of the intellect.  Hence of all people children are the most imaginative.  They abandon themselves without reserve to every illusion.  Every image which is strongly presented to their mental eye produces on them the effect of reality.  No man, whatever his sensibility may be, is ever affected by Hamlet or Lear, as a little girl is affected by the story of poor Red Riding-hood.  She knows that it is all false, that wolves cannot speak, that there are no wolves in England.  Yet in spite of her knowledge she believes; she weeps; she trembles; she dares not go into a dark room lest she should feel the teeth of the monster at her throat.  Such is the despotism of the imagination over uncultivated minds.

In a rude state of society men are children with a greater variety of ideas.  It is therefore in such a state of society that we may expect to find the poetical temperament in its highest perfection.  In an enlightened age there will be much intelligence, much science, much philosophy, abundance of just classification and subtle analysis, abundance of wit and eloquence, abundance of verses, and even of good ones; but little poetry.  Men will judge and compare; but they will not create.  They will talk about the old poets, and comment on them, and to a certain degree enjoy them.  But they will scarcely be able to conceive the effect which poetry produced on their ruder ancestors, the agony, the ecstasy, the plenitude of belief.  The Greek Rhapsodists, according to Plato, could scarce recite Homer without falling into convulsions.  The Mohawk hardly feels the scalping knife while he shouts his death-song.  The power which the ancient bards of Wales and Germany exercised over their auditors seems to modern readers almost miraculous.  Such feelings are very rare in a civilised community, and most rare among those who participate most in its improvements.  They linger longest amongst the peasantry.