Explain the quote: But Shadwell's genuine night admits no ray, His rising fogs prevail upon the day.
These two lines are taken from Mac Flecknoe (written ca. 1678, published in 1682). Mac Flecknoe, a verse mock-heroic satire by John Dryden (1631-1700), is a direct attack on Thomas Shadwell (1642-1692), another prominent poet of the time, who is appointed the heir to a kingdom of poetic dullness.
Mac Flecknoe is the outcome of a series of disagreements between Thomas Shadwell and Dryden. Their disagreements were political, religious and literary.
2) Religion: Shadwell offended Dryden when he satirized Catholic and Anglican priests in a play (The Lancashire-Witches, and Teque o Divelly the Irish-Priest, 1682). Dryden was considering the idea of converting to Catholicism, which he did in 1686.
3) Literature: Shadwell and Dryden disputed about who was the best writer: Shakespeare (Dryden) or Ben Jonson (Shadwell).
As a consequence, this Juvenalian satire, which is an ad hominem attack, is also a piece of literary criticism. The lines “But Shadwell’s genuine night admits no ray, / His rising fogs prevail upon the day” (ll. 23-24) refer metaphorically to Shadwell’s lack of brilliance, to his stupidity (according to Dryden). For Dryden, Shadwell, whose poetry was largely dismissible, was the Lord of misrule. In the poem his only attributes were indeed a mighty mug of potent ale and a crown of poppies.
As MacFlecknoe is a mock-heroic epic, it's written in a style similar to that of the epics of ancient Rome and Greece. The difference, however, is that here there's considerably more "mock," and not much in the way of "heroic" involved. So Dryden is heaping constant abuse upon poor old Shadwell, but doing it in a very clever way, making it more difficult for his hapless victim to respond. After all, it's so much harder to counter someone's insults if they're couched in skillful poetic language than if they're expressed in profanities.
Dryden loathes Shadwell for many reasons, but basically he thinks he's a bit of an idiot. And as Dryden is a highly skilled wit and poet, he's not about to come right out and say, "That Shadwell's a total idiot." So he's going to use metaphor to hammer home his point:
Some beams of wit on other souls may fall,
Strike through and make a lucid interval;
But Shadwell's genuine night admits no ray,
His rising fogs prevail upon the day:
Other writers are witty and inspired, but not Shadwell. He is so stupid, remaining in a state of permanent night and fog, intellectually speaking, that no shafts of wit could ever possibly break through.