Throughout the Essay of Dramatic Poesy Dryden treats drama as a form of imaginative literature, and hence his remarks on drama apply to poetry as well. The very definition of a play, given in the very beginning, is expressive of his view of poetry.
Drama is defined as "just and lively image of human nature, representing its passions and humours, and the changes of fortune to which it is subject, for the delight and instruction of mankind." According to this definition, drama is an 'image' of' human nature' and that the image is 'just' as well as 'lively'. By using the word 'just' Dryden seems to imply that literature imitates (and not reproduces) human actions. For Dryden, poetic imitation is different from an exact, servile copy of reality, for the imitation is not only 'just', it is also 'lively'.
While David Daiches takes 'lively' to mean interesting—the antithesis to dull—R.A. Scott-James takes 'lively' to mean 'beautiful' and so delightful. The poet is a maker or creator, and he aims at making something more beautiful. He says, "the poet does not leave things as he finds them, but handles them, treats them, "heightens" their quality, and so creates something that is beautiful, and his own."
In other words, in poetry there is no more reproduction of reality, the poet has 'imagination' and it is by the shaping power of his imagination that the poet selects, orders, re-arranges his material, and thus gives a more heightened and beautiful version of reality. It is not slavish imitation, but imaginative creation that Dryden means by the 'just and 'lively' image of human nature. His image of human nature is 'just' because it is basically true, and it is also 'lively' for it is a more 'heightened', and beautiful reproduction. Dryden's Essay makes it quite clear that he lays more emphasis on the 'liveliness' of the image than on its 'justness'. Thus the irregular plays of Shakespeare are praised for their 'liveliness'.
According to Dryden, "a bare imitation, will not serve the ends of poetry, which are to instruct and delight, and poetry instructs as it delights". Instruction is secondary, and delight is the first, the primary function of poetry. In this way in emphasising 'delight' of poetry, Dryden is far in advance of his age in which instruction was regarded as the chief aim of poetry.
The question then arises how poetry fulfils this function. How does it 'instruct' and how does it 'delight'? According to, David Daiches, the instruction which poetry gives is psychological, it is a better understanding of human nature, a keener insight into the working of the human mind and heart that we get from poetry. The function of poetry would thus be to inform the reader, in a lively and agreeable way, of what human nature is like. Literature would be a form of knowledge, and it would bear the same relation to psychology as in Sidney it does to ethics. That is, while for Sidney the poet makes vivid and impressive, by his imaginary examples, the ideas of the moral philosopher, so for Dryden the poet makes vivid and impressive, by his imaginary examples, the knowledge of the psychologist.
As regards giving pleasure or delight, it arises from a contemplation of the beautiful. This aesthetic delight has the power to move, the power of transport, the power, in Dryden's words, "to affect the soul, excite the passion, and above all to move admiration." The soul is 'moved' and 'transported' to the appreciation of the beautiful, and since the beautiful in human actions and passions is also, 'the noble', 'the good', and 'the moral', an appreciation of beauty means an appreciation of the good and the noble also.
It is in this way that poetry instructs as it delights. For this purpose a bare imitation of reality will not do, but reality must be selected, ordered, and shaped by the poet's imagination, just as skilled workmen shapes his raw material to create or make beautiful works of art. Poetic imagination transforms and transmutes reality, but in affecting such transmutation the poet may not remain 'just'; he may falsify reality. Therefore, the excesses of poetic imagination must be cured and controlled, and such a control is exercised by the judgment of the poet. Thus imagination enables a poet to give a 'lively' picture of human nature, while his judgment keeps the picture 'just'.
Thus Dryden's concept of poetic imitation is not mere slavish copying of nature. Poetic representation is not mere imitation, for it is the work of a poet, or maker, or creator, whose concern is to produce something that is beautiful. To Dryden, the artist aims at making something more beautiful than life. It is only such a 'making' that can enable poetry to perform the function proper to it.