Adapted from the Advertisement to Lyrical Ballads by William Wordsworth (1798)

It is the honorable characteristic of Poetry that its materials are to be found in every subject which can interest the human mind. The evidence of this fact is to be sought, not in the writings of Critics, but in those of Poets themselves.

The majority of the following poems are to be considered as experiments. They were written chiefly with a view to ascertain how far the language of conversation in the middle and lower classes of society is adapted to the purposes of poetic pleasure. Readers accustomed to the gaudiness and inane phraseology of many modern writers, if they persist in reading this book to its conclusion, will perhaps frequently have to struggle with feelings of strangeness and awkwardness: they will look round for poetry, and will be induced to enquire by what species of courtesy these attempts can be permitted to assume that title. It is desirable that such readers, for their own sakes, should not suffer the solitary word Poetry, a word of very disputed meaning, to stand in the way of their gratification; but that, while they are perusing this book, they should ask themselves if it contains a natural delineation of human passions, human characters, and human incidents; and if the answer be favorable to the author's wishes, that they should consent to be pleased in spite of that most dreadful enemy to our pleasures, our own pre-established codes of decision.

Readers of superior judgement may disapprove of the style in which many of these pieces are executed it must be expected that many lines and phrases will not exactly suit their taste. It will perhaps appear to them, that wishing to avoid the prevalent fault of the day, the author has sometimes descended too low, and that many of his expressions are too familiar, and not of sufficient dignity. It is apprehended, that the more conversant the reader is with our elder writers, and with those in modern times who have been the most successful in painting manners and passions, the fewer complaints of this kind will he have to make.

An accurate taste in poetry, and in all the other arts, Sir Joshua Reynolds has observed, is an acquired talent, which can only be produced by severe thought, and a long continued intercourse with the best models of composition. This is mentioned not with so ridiculous a purpose as to prevent the most inexperienced reader from judging for himself; but merely to temper the rashness of decision, and to suggest that if poetry be a subject on which much time has not been bestowed, the judgement may be erroneous, and that in many cases it necessarily will be so.

Adapted from An Enquiry Concerning Human Understanding by David Hume (1748)

Everyone will readily allow that there is a considerable difference between the perceptions of the mind, when a man feels the pain of excessive heat, or the pleasure of moderate warmth, and when he afterwards recalls to his memory this sensation, or anticipates it by his imagination. These faculties may mimic or copy the perceptions of the senses, but they never can entirely reach the force and vivacity of the original sentiment. The utmost we say of them, even when they operate with greatest vigor, is, that they represent their object in so lively a manner that we could almost say we feel or see it. But, except the mind be disordered by disease or madness, they never can arrive at such a pitch of vivacity as to render these perceptions altogether undistinguishable. All the colors of poetry, however splendid, can never paint natural objects in such a manner as to make the description be taken for a real landscape. The most lively thought is still inferior to the dullest sensation.

We may observe a like distinction to run through all the other perceptions of the mind. A man in a fit of anger is actuated in a very different manner from one who only thinks of that emotion. If you tell me that any person is in love I easily understand your meaning, and form a just conception of his situation, but never can mistake that conception for the real disorders and agitations of the passion. When we reflect on our past sentiments and affections, our thought is a faithful mirror and copies its objects truly, but the colors which it employs are faint and dull in comparison of those in which our original perceptions were clothed. It requires no nice discernment or metaphysical head to mark the distinction between them.

Here, therefore, we may divide all the perceptions of the mind into two classes or species, which are distinguished by their different degrees of force and vivacity. The less forcible and lively are commonly denominated "thoughts" or "ideas." The other species want a name in our language, and in most others; I suppose because it was not requisite for any but philosophical purposes to rank them under a general term or appellation. Let us, therefore, use a little freedom, and call them "impressions," employing that word in a sense somewhat different from the usual. By the term "impression," then, I mean all our more lively perceptions, when we hear, or see, or feel, or love, or hate, or desire, or will. And impressions are distinguished from ideas, which are the less lively perceptions, of which we are conscious when we reflect on any of those sensations or movements above mentioned.