The "social union" the speaker mentions sounds a lot like the eighteenth-century Enlightenment theory of the social contract by guys like Thomas Hobbes, John Locke, and Jean-Jacques Rousseau. (8)
Famous References to this Poem:
John Steinbeck's famous novel Of Mice and Men is a reference to this poem, specifically lines 39-40. Like Burns' poem, Steinbeck's novel is about how even the most carefully-laid plans (like George's plan to get a farm with Lenny) can get all screwed up.