Many of the classical and continental poets admired by Chaucer used the dream-poem, with its personalized allegory of the order of things, as a vehicle for theological or ethical argument; some of the best-known were Cicero's Dream of Scipio Africanus, Alain de L'Isle's Plaint of Nature, and The Romance of the Rose (an English translation of which appears to have been Chaucer's first major work as a poet). Even Dante's Divine Comedy, with its most serious of settings, takes many of its cues from this tradition.
In the House of Fame, we see an explanation for the "fickleness" of Fame, both eternal (the names in stone) and ephemeral (the names carved in ice). We also get a treatise on acoustics, by way of explaining how the sounds of human chatter reach to the heavens, where the blind goddess Fame heralds them with one sort of trumpet -- or another.
Some order is promised at the end, when a "man of great authority" -- imagined by some to have been meant to have been Dante himself -- steps forward -- but this, alas, turns out to be the last line of the poem. Unless some forgotten fragment turns up, the world will never know what this man might have said, or done.
NB: You can skip the latter portion of Book I (lines 140-496) which rehearses the story of the Æneid.